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Clinical and histopathological features of malignant melanoma in germline CDKN2A mutation families
Abstract
Primary cutaneous malignant melanomas (CMMs) from 26 individuals belonging to nine families with an identified mutation were clinically and histopathologically compared with 78 matched CMM controls and with a population-based series of CMMs ( = 667). All tumours were histopathologically re-examined. CDKN2A-associated cases were significantly less invasive compared with the matched controls, with an adjusted odds ratio (adjOR) of 2.9 and a 95% confidence interval (CI) of 1.0-8.1 ( = 0.04). According to the odds ratio (OR) values, CDKN2A-associated cases seemed to have tumours more often located on the head and neck (adjOR 2.9, 95% CI 0.6-13.7), with less inflammation (adjOR 0.7, 95% CI 0.3-1.8) and regression (adjOR 0.6, 95% CI 0.2-1.8) but more frequent histological ulceration (adjOR 1.9, 95% CI 0.6-5.8). In comparison with the population-based material, CDKN2A-associated cases were significantly younger at diagnosis (crude OR 3.5, 95% CI 1.6-7.5, divided at 50 years) and had less regressive reaction in their tumours (crude OR 0.35, 95% CI 0.2-0.8). No significant differences were seen for tumour thickness between the different groups. On multivariate analysis, the overall survival was significantly worse for thicker tumours and older age ( = 0.04 for both). To our knowledge this is the first description of the histopathological features of CMMs from families with mutations in the CDKN2A gene.
... 12 Melanoma occurs approximately 15 years earlier in CDKN2A mutation carriers than in the general population, 13 with a median age of onset around 33-45 years compared to 53-61 years in the general population. 14,15 Melanoma may occur in adolescence or early adulthood with some of the youngest reported cases at 13 years of age. 16,17 Conversely, in a population-based series of twenty childhood melanomas, only one CDKN2A mutation was identified. ...
... 22 Others have found that sparser inflammation and lack of regression may be associated features. 15 Similar to sporadic melanoma, somatic mutations in melanomas associated with germline CDKN2A mutation include BRAF and NRAS, though BRAF tends to be less common and NRAS mutations more common in CDKN2A germline mutation associated melanoma. 23,24 This article is protected by copyright. ...
Nearly 15% of melanomas occur in patients with a family history and a subset of these patients have a germline mutation in a melanoma predisposing gene. CDKN2A mutations are responsible for the majority of hereditary melanoma, but many other susceptibility genes have been discovered in recent years, including CDK4, TERT, ACD, TERF2IP, POT1, MITF, MC1R, and BAP1. Additionally, melanoma risk is increased in mixed cancer syndromes caused by mutations in PTEN, BRCA2, BRCA1, RB1, and TP53. While early onset, multiple tumors, and family cancer history remain the most valuable clinical clues for hereditary melanoma, characteristic epithelioid cytology of melanocytic tumors may suggest an underlying BAP1 mutation. Herein, we review the clinical and histopathologic characteristics of melanocytic tumors associated with these germline mutations and discuss the role of genetic counseling.
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... Particularly, most of these studies have not specified if the compared CMs are first (index cases) or subsequent (incident cases) cases, and they have used as controls sporadic CMs developed by non-genotyped patients. This finding may lead to bias since most melanoma-prone families are, unlike most sporadic cases, under close dermatologic surveillance with the aim to diagnose tumours at earlier or premalignant stages [2,25,31,36,39]. ...
... Therefore, we could hypothesize that the anatomical distribution of CMs in carriers of an autosomal dominant CDKN2A germline mutation (which confers a constitutional risk to the entire skin surface) might be independent of gender and could be influenced by other factors such as intermittent exposure to UV rays on the trunk and lower limbs. Conversely, the penetrance of the CDKN2A mutation (in terms of risk of developing CM) appears to be higher among females, as confirmed previously by other authors (Table 1) [2,25,31,36,39]. ...
Germline mutations on the CDKN2A gene, the most important known genetic factors associated with cutaneous melanomas (CMs), predispose carriers to multiple primary CMs (MPMs) with higher frequency and younger onset compared to non-carriers. Most of the largest published studies concerning clinical and histological characteristics of CMs with CDKN2A mutation carriers did not specify if the described CMs are first or subsequent to the first, and they used sporadic CMs from non-genotyped patients as controls. We conducted a single-centre observational study to compare clinical and histological CM features of 32 unrelated carriers (MUT) of 5 germline CDKN2A mutations (one of which was never previously described) compared to 100 genotyped wild-type (WT) patients. We stratified the data based on time of diagnosis, anatomical site and histological subtype of CMs, demonstrating several significant unreported differences between the two groups. MUT developed a higher number of dysplastic nevi and MPMs. We proved for the first time that anatomical distribution of CMs in MUT was independent of gender, unlike WTs. MUTs developed in situ and superficial spreading melanomas (SSMs) more frequently, with significantly higher number of SSMs on the head/neck. In MUTs, Breslow thickness was significantly lower for all invasive CMs. When CMs were stratified on the basis of the time of occurrence, statistical significance was maintained only for SSMs subsequent to the first. In WTs, Clark level was significantly higher, and ulceration was more prevalent than in MUTs. Significant differences in ulceration were observed only in SSMs. In nodular CMs, we did not find differences in terms of Breslow thickness or ulceration between WTs and MUTs. In situ CMs developed 10 years earlier in MUTs with respect to WTs, whereas no significant differences were observed in invasive CMs. In contrast to those reported previously by other authors, we did not find a difference in skin phototype.
... The second known mutation is found on the CDK4 gene on chromosome 12, which occurs in approximately 3% of melanoma families (4). Reports on the mean age of diagnosis of the first melanoma in these families range from 33-36 years in patients with CDKN2A gene mutation, to 41-45 years in patients without a CDKN2A gene mutation (with an unknown mutation) (2,5,6). In patients with a CDKN2A mutation the lifetime risk for developing melanoma is 70% at the age of 80 years, with a 30% chance of developing multiple melanomas (5,7). ...
... Reports on the mean age of diagnosis of the first melanoma in these families range from 33-36 years in patients with CDKN2A gene mutation, to 41-45 years in patients without a CDKN2A gene mutation (with an unknown mutation) (2,5,6). In patients with a CDKN2A mutation the lifetime risk for developing melanoma is 70% at the age of 80 years, with a 30% chance of developing multiple melanomas (5,7). ...
Approximately 10% of all melanomas occur in subjects with a family history of melanoma. This retrospective follow-up study investigated the characteristics of patients with familial melanoma who made unscheduled visits to our pigmented lesions clinic, and the diagnosis of excised lesions. A total of 110 out of 1,267 (9%) patients made at least one unscheduled visit between May 2011 and February 2016. Histopathology was taken from 59 patients. Thirty-four naevi, 7 melanomas and 3 basal cell carcinomas were detected. All patients with melanoma were CDKN2A carriers and all melanomas were discovered at a very early stage. In this patient population it appears to be safe to limit visits to once or twice yearly, provided patients are easily able to make an unscheduled extra visit if they have a worrisome lesion. We recommend supporting patients' self-reliance by stimulating them to carry out self-examination of their skin.
... Several studies have compared patient-and tumor-specific factors among germline CDKN2A mutation carriers and noncarriers. In summary, the only consistent finding has been that CDKN2A mutation carriers are younger at melanoma diagnosis whereas findings on differences in tumor-specific features such as body site of the primary tumor, invasiveness, thickness, and histological type have been statistically nonsignificant or divergent (12)(13)(14)(15)(16). There have been indications that primary melanomas from CDKN2A mutation carriers are less advanced at diagnosis; however, in most of the studies, control subjects have consisted of sporadic melanoma cases (12)(13)(14). ...
... In summary, the only consistent finding has been that CDKN2A mutation carriers are younger at melanoma diagnosis whereas findings on differences in tumor-specific features such as body site of the primary tumor, invasiveness, thickness, and histological type have been statistically nonsignificant or divergent (12)(13)(14)(15)(16). There have been indications that primary melanomas from CDKN2A mutation carriers are less advanced at diagnosis; however, in most of the studies, control subjects have consisted of sporadic melanoma cases (12)(13)(14). This is of importance because members of melanoma families are normally enrolled in dermatologic follow-up programs aimed at diagnosing melanomas at earlier or premalignant stages while sporadic melanoma cases have usually not participated in any such programs. ...
Background:
Germline mutations in CDKN2A have been associated with increased risk of melanoma and tobacco-related cancers in respiratory and upper digestive tissues. In CDKN2A wild-type (wt) melanoma families, other known high-risk, melanoma-predisposing mutations are rare, and no increased risk has been observed for nonskin cancers in this group. This study is the first to compare survival in germline CDKN2A mutated (mut) and nonmutated melanoma cases.
Methods:
Melanoma-prone families participating in this study were identified through a nationwide predictive program starting in 1987. Information on cancer diagnoses (types, stages, and dates) and deaths (causes and dates) were obtained through the Swedish Cancer Registry and Cause of Death Registry. Kaplan Meier and Cox proportional hazards regression models were used to assess survival in CDKN2A(mut) (n = 96) and CDKN2A(wt) (n = 377) familial melanoma cases and in matched sporadic melanoma cases (n = 1042). All statistical tests were two-sided.
Results:
When comparing CDKN2A(mut) and CDKN2A(wt) melanoma cases, after adjusting for age, sex, and T classification, CDKN2A(mut) had worse survival than melanoma (hazard ratio [HR] = 2.50, 95% confidence interval [CI] = 1.49 to 4.21) and than nonmelanoma cancers (HR = 7.77, 95% CI = 3.65 to 16.51). Compared with matched sporadic cases, CDKN2A(mut) cases had statistically significantly worse survival from both melanoma and nonmelanoma cancers while no differences in survival were seen in CDKN2A(wt) compared with sporadic cases.
Conclusions:
CDKN2A(mut) cases had statistically significantly worse survival than nonmelanoma cancers and, intriguingly, also from melanoma, compared with melanoma cases with no CDKN2A mutations. Further studies are required to elucidate possible mechanisms behind increased carcinogen susceptibility and the more aggressive melanoma phenotype in CDKN2A mutation carriers.
... However, it is to be noted that CDKN2A mutations are extremely rare in population based melanoma cases. The collation of multiple studies comparing germline CDKN2A mutation carriers with non-carriers has also determined that CDKN2A mutation carriers have a lower median age of melanoma diagnosis [27,[105][106][107][108]]. ...
Melanoma is an extremely aggressive malignancy with a poor prognosis in advanced disease. While GWAS and exome analysis have helped to identify loci linked to the development of the disease, these studies have explained predisposition to melanoma in only a fraction of cases. Thus, the majority of the genetic factors that contribute to the pathogenesis of melanoma are yet to be defined. This project aims at identifying novel genes and pathways involved in the development of familial melanoma, and also identify loci which predispose individuals to disease development. 308 individuals from 133 different families previously diagnosed with melanoma were sequenced through a mixture of exome or whole genome sequencing. Multiple workflows were established to analyse the dataset for novel driver mutations. A novel approach of combining association and linkage analysis was established for the variants in the coding region to identify genes with high burden of mutations where the variants segregated with the disease within the pedigrees. The role of non-coding variants and structural variants in melanoma onset was also investigated through additional workflows in the whole-genome sequenced individuals. Non-synonymous mutations were found in CDKN2A, BRCA1, POT1 and BAP1. Disruptive variants were also observed in novel genes such as EXO5, TP53AIP and AMER1. An increased burden on variants in transcription factor binding motifs were observed in genes including SYK and SRC. A large deletion upstream of CDKN2A was identified. Genes including ATR and FAT1 were identified to have a higher burden of disruptive variants that segregated with the disease within the cases through the novel combined association-linkage analysis. Disruptive germline variants that could play a role in familial melanoma development were identified in multiple genes through a combination of several approaches.
... Various studies have also demonstrated a much lower median age of onset of CMM in patients from germline CDKN2A mutation families (33-45 years) compared to patients without a CDKN2A mutation (53-61 years); this trend remains largely consistent irrespective of a geographic region. 3,30,31 There are reports of CDKN2A kindreds where CMM has occurred in the early teens and twenties. 20 As would be expected, the increased risk of CMM in these patients does not diminish with their first diagnosis as they also have a much higher 5-year cumulative incidence of a second melanoma compared to mutationnegative controls (23.4% and 2.3%, respectively). ...
Malignant melanoma is considered the most lethal skin cancer if it is not detected and treated during its early stages. About 10% of melanoma patients report a family history of melanoma; however, individuals with features of true hereditary melanoma (ie, unilateral lineage, multigenerational, multiple primary lesions, and early onset of disease) are in fact quite rare. Although many new loci have been implicated in hereditary melanoma, CDKN2A mutations remain the most common. Familial melanoma in the presence of multiple atypical nevi should raise suspicion for a germline CDKN2A mutation. These patients have a high risk of developing multiple primary melanomas and internal organ malignancies, especially pancreatic cancer; therefore, a multidisciplinary approach is necessary in many cases. The value of dermoscopic examination and total body photography performed at regular intervals has been suggested by a number of studies, and should therefore be considered for these patients and their first-degree relatives. In addition, genetic counseling with the possibility of testing can be a valuable adjunct for familial melanoma patients. This must be performed with care, however, and only by qualified individuals trained in cancer risk analysis.
... Applied to melanoma risk and CDKN2A germline mutations, some genetic information is of limited use. For instance, genotype-phenotype correlation obtained through pathology analysis would not help, because there are no strong particular features of melanoma developed by CDKN2A carriers as compared to sporadic cases [Masback et al., 2002]. Loss of heterozygosity (LOH) is an indicator but not a strong proof of pathogenicity for a missense variant, as it could indicate, in addition to the missense variant, the presence of an undetected complex genetic event targeting the same gene. ...
Germline mutations of the CDKN2A gene are found in melanoma-prone families and individuals with multiple sporadic melanomas. The encoded protein, p16(INK4A), comprises four ankyrin-type repeats, and the mutations, most of which are missense and occur throughout the entire coding region, can disrupt the conformation of these structural motifs as well as the association of p16(INK4a) with its physiological targets, the cyclin-dependent kinases (CDKs) CDK4 and CDK6. Assessing pathogenicity of nonsynonymous mutations is critical to evaluate melanoma risk in carriers. In the current study, we investigate 20 CDKN2A germline mutations whose effects on p16(INK4A) structure and function have not been previously documented (Thr18_Ala19dup, Gly23Asp, Arg24Gln, Gly35Ala, Gly35Val, Ala57Val, Ala60Val, Ala60Arg, Leu65dup, Gly67Arg, Gly67_Asn71del, Glu69Gly, Asp74Tyr, Thr77Pro, Arg80Pro, Pro81Thr, Arg87Trp, Leu97Arg, Arg99Pro, and [Leu113Leu;Pro114Ser]). By considering genetic information, the predicted impact of each variant on the protein structure, its ability to interact with CDK4 and impede cell proliferation in experimental settings, we conclude that 18 of the 20 CDKN2A variants can be classed as loss of function mutations, whereas the results for two remain ambiguous. Discriminating between mutant and neutral variants of p16(INK4A) not only adds to our understanding of the functionally critical residues in the protein but provides information that can be used for melanoma risk prediction.
... Melanoma risk is 30-70 times higher in individuals with a significant family history compared with the general population. 40,41 Familial melanomas arise through a dominantly inherited susceptibility to melanoma and many are characterised by germ-line mutations in specific genes. The lifetime risk of melanoma in individuals who carry these mutations is very high, but varies among geographical regions. ...
Background:
Inherited mutations in the CDKN2A gene are among the strongest known risk factors for cutaneous melanoma. Further, previous studies have reported inferior melanoma-specific survival in CDKN2A mutation carriers.
Objectives:
Here, the melanoma-specific survival was studied, depending on CDKN2A carrier status and if the melanomas had been diagnosed before or after families were included in a surveillance program.
Methods:
Melanoma-prone families participating in this study were identified through a nationwide preventive program starting in 1987. Information on melanoma tumours and deaths was obtained through the Swedish Cancer Registry and Cause of Death Registry. Kaplan-Meier and Cox proportional hazards regression models were used to assess melanoma-specific survival in four defined cohorts, CDKN2A mutation (MUT) carriers with first invasive melanoma before or after inclusion [MUT-pre (n = 53) and MUT-post (n = 43)] and likewise in CDKN2A wild type (WT) cases [WT-pre (n = 255) and WT-post (n = 122)].
Results:
The MUT-pre and MUT-post cases were diagnosed with their first invasive melanoma at a significantly younger ages (38 and 42 years, respectively) than the WT-pre and WT-post cases (48 and 57 years, respectively). The melanomas in the MUT-pre had significantly higher T stage compared with MUT-post (p = 0.006), whereas no such difference was seen comparing WT-pre with WT-post (p = 0.849). MUT-pre had compared with WT-pre, significantly worse melanoma-specific survival, unadjusted (HR 2.33, 95% CI 1.33-4.08, p = 0.003) adjusted (HR 2.70, 95% CI 1.46-5.00, p = 0.001). However, the MUT-post cases had compared with the WT-post cases, no significant survival differences.
Conclusion:
This study is the first to address the impact on survival from introducing a dermatologic surveillance program to familial melanoma cases with or without CDKN2A mutations. The CDKN2A-mut carriers appeared to have a clear benefit with less advanced melanomas diagnosed and better melanoma-specific survival after inclusion. Among the CDKN2A-wt cases, the effect of the inclusion on the studied outcomes was less evident.
Adolescent Melanoma & Genetic Susceptibility; Implications for Management and Family Risk Assessment.”
Over the last several decades the worldwide incidence of melanoma in Caucasians has increased markedly, with the highest rates found in some countries considered epidemic. This is direcly related with ultraviolet irradiation from natural and artificial light, and long-life expectancy, but predisposing conditions and genetic factors are important. It is now appreciated that transformation of melanocytes into malignant melanoma involves the interplay between different predisposing factors (marckers and precursors ones): the numbers of moles -specially atypic and congenital ones- and white race compromise more than half of the population at risk, but not all. Changes in the stile of life, intense sun exposure early in life and World globalization are directly related with melanoma incidence affecting an increasingly younger population. Greater emphasis is being placed on professional education, screening and identification of high risk populations.
The incidence of melanoma has increased dramatically during the past several decades among Caucasian populations. Mortality rates continue to rise overall, but in some populations, such as females, the mortality rate has plateaued or even fallen. The reasons for these trends are not altogether obvious, but may involve changes in attitudes and behaviors with regard to sun exposure or an increased public awareness to the early signs of melanoma diagnosis.
Familial atypical multiple mole melanoma syndrome (FAMMMS) is an autosomal dominant genodermatosis characterized by multiple melanocytic nevi, usually more than 50, and a family history of melanoma. It is known to be associated with carcinoma of pancreas and other malignancies involving gastrointestinal tract, breast, lung, larynx, and skin in the kindred. There is no published report of FAMMMS in dark-skinned individuals. We report a case of FAMMMS in a dark-skinned adult Indian male, who had multiple extensive nevi all over the body and oral mucosa; associated with malignant melanoma, squamous cell carcinoma (Marjolin's ulcer), and carcinoma of pancreas. His father had died of carcinoma of lung and his sister had a partial phenotypic expression. The clinical presentation of the case is discussed with review of literature.
About 10% of cutaneous malignant melanomas (CMM) occur in individuals with a family history of melanoma. In 20% to 40% of melanoma families germline mutations in CDKN2A are detected. Knowledge of the clinicohistologic characteristics of melanomas and patients from these families is important for optimization of management strategies, and may shed more light on the complex interplay of genetic and environmental factors in the pathogenesis of melanoma.
We sought to investigate the clinical and histologic characteristics of CMM in CDKN2A-mutated families.
Clinical and histologic characteristics of 182 patients with 429 CMM from families with a founder mutation in CDKN2A (p16-Leiden mutation) were compared with 7512 patients with 7842 CMM from a population-based cancer registry.
Patients with p16-Leiden had their first melanoma 15.3 years younger than control patients. The 5-year cumulative incidence of second primary CMM was 23.4% for patients with p16-Leiden compared with 2.3% for control patients. The risk of a second melanoma was twice as high for patients with p16-Leiden who had their first melanoma before age 40 years, compared with older patients with p16-Leiden. Unlike control patients, there was no body site concordance of the first and second melanoma in patients with p16-Leiden and multiple primary melanomas. Patients with p16-Leiden had significantly more superficial spreading, and less nodular and lentiginous melanomas.
Ascertainment of patients with p16-Leiden was family based. The study was performed in families with a founder mutation, the p16-Leiden mutation.
Our findings are consistent with a pathogenic pathway of melanoma development from nevi, starting early and ongoing throughout life, and not related to chronic sun exposure.
Multiple Endocrine Neoplasia type 1 (MEN1) is a rare hereditary endocrine cancer syndrome characterized primarily by tumors of the parathyroid glands (95% of cases), endocrine gastroenteropancreatic (GEP) tract (30-80% of cases), and anterior pituitary (15-90% of cases) (Figure 1) (1). Other endocrine and non-endocrine neoplasms including adrenocortical and thyroid tumors, visceral and cutaneous lipomas, meningiomas, facial angiofibromas and collagenomas, and thymic, gastric, and bronchial carcinoids also occur (Table 1 and Table 2) (2-8). The phenotype of MEN1 is broad, and over 20 different combinations of endocrine and non-endocrine manifestations have been described (9-13). MEN1 should be suspected in patients with an endocrinopathy of two of the three characteristic affected organs, or with an endocrinopathy of one of these organs plus a first-degree relative affected by MEN1 syndrome. MEN1 patients usually have a family history of MEN1. Inheritance is autosomal dominant; any affected parent has a 50% chance to transmit the disease to his or her progeny. MEN1 gene mutations can be identified in 70-95% of MEN1 patients. Many endocrine tumors in MEN1 are benign and cause symptoms by overproduction of hormones or local mass effects, while other MEN1 tumors are associated with an elevated risk for malignancy. About one third of patients affected with MEN1 will die early from an MEN1-related cancer or associated malignancy. Entero-pancreatic gastrinomas and thymic and bronchial carcinoids are the leading cause of morbidity and mortality. Consequently, the average age of death in individuals with MEN1 is significantly lower (55.4 years for men and 46.8 years for women) than that of the general population.
The clinical manifestations of hereditary skin cancer syndromes depend upon the interplay between environmental and genetic factors. Familial melanoma occurs in the setting of hereditary susceptibility, with a complex phenotype of early age of onset, multiple atypical moles, multiple primary melanomas, multiple melanomas in the family, and in some instances pancreatic cancer. Identification of individuals who may have a hereditary susceptibility for the development of melanoma is essential to provide an opportunity for primary prevention, and to target high-risk groups for early diagnosis and treatment. Consequently, the surgeon as one of the primary caregivers should be familiar with hereditary skin cancer syndromes and their pathogenesis, diagnosis, management, and surveillance recommendations. This article discusses a practical approach for some of the issues likely encountered by the surgeon in the management of familial melanoma and non-melanoma skin cancer.
Spontaneous animal tumors appear to be highly suitable models to study human oncology and cancer therapy. The aim of this study was to characterize the clinical and histological features of hereditary melanocytic lesions found in the French herd of melanoblastoma-bearing Libechov minipigs (MeLiM) and their Duroc crossbreeds. Clinically, we discriminated between three types of melanocytic skin lesions, which offer a lesion continuum from lentigo to metastatic melanomas. More than 70% of these lesions appear on piglets before they are 3 months old and preferentially on homogeneous black coat piglets. The incidence of melanoma reaches 50% in MeLiM. Most of the highly invasive melanomas regressed spontaneously in the first year of the piglet's life and the regression was followed by hair, skin and iris depigmentation. A histopathological study was conducted according to the human melanoma classification. Except for lentigo maligna, we observed the three main types of human melanoma in swine [superficial spreading melanoma (SSM), nodular or unclassified melanoma] with an excess of SSM (59-67%). The histological events leading to total spontaneous regression are chronologically described. The genetic predisposition, the high incidence of melanoma, the clinical and histopathological features similar to the human disease and the high rate of spontaneous regression offer an opportunity to use this model for studying genetic events controlling melanoma development and regression and the biological mechanisms involved in oncogenesis and anti-cancerous self-defense.
The clinical phenotypes of familial melanoma syndromes and genetic and environmental interactions are reviewed to summarize the current status of the field and to identify gaps in molecular and clinical investigations.
The familial melanoma syndromes are associated with germline mutations in three highly penetrant gene products: p16, alternate reading frame, and cyclin-dependent kinase 4. Certain variants in a low-penetrance gene, MC1R, the melanocortin 1 receptor gene, increase melanoma risk to a lesser extent and act as a genetic modifier when cosegregating with a deleterious p16 gene. The penetrance of these melanoma-predisposing genes is largely influenced by ultraviolet exposure across geographic latitude. Yet cumulative studies are conflicting on whether ultraviolet radiation, including sunburns, early childhood and adolescent sun exposure, and chronic exposure, increases melanoma risk in familial melanoma. To date, the clinical phenotypes of increased number of atypical nevi and nevi body distribution are independent risk factors for melanoma risk, regardless of family history. The atypical mole syndrome cannot reliably predict melanoma germline mutations but increases melanoma risk in p16 mutation carriers. Familial melanoma patients develop melanomas earlier and are prone to developing multiple primary melanomas. Other than these two differences, familial and sporadic melanoma share similar histopathology, prognostic factors, and survival rates.
Familial melanoma is an excellent human model system for the investigation of melanoma. Understanding genotype-phenotype and environmental relationships in familial melanoma will likely lead to improved understanding of pathogenesis for all melanoma patients.
Oncologists who are aware of the progress in hereditary cancer syndrome diagnosis, and, in particular, of how this effort may be effectively facilitated through a comprehensive family history in concert with molecular genetic studies, are in the envious position of designing highly targeted screening and management programs for the membership of these cancer-prone families. The Lynch syndrome is discussed as a clinical model wherein the presence of mismatch repair mutations provides a high level of diagnostic certainty for the initiation of targeted cancer screening and management. The familial atypical multiple mole melanoma-pancreatic cancer (FAMMM-PC) syndrome, on the other hand, provides another model with cancer-control potential. Given its phenotypic features of multiple atypical nevi, high total body mole count and cutaneous malignant melanoma, coupled with the integral association of PC in a subset of FAMMM kindreds with the CDKN2A germline mutation, this may result in a perhaps lower level of diagnostic certainty when compared with the Lynch syndrome. This knowledge may impact upon progress in the earlier diagnosis of melanoma and provide an impetus for creative diagnostic methods in PC, a disease that, at this time, demonstrates a mortality rate virtually identical to its incidence rate.
Background:
: Inherited mutations in the CDKN2A tumor suppressor gene, which encodes the p16(INK4a) protein, and in the cyclin-dependent kinase 4 (CDK4) gene confer susceptibility to cutaneous malignant melanoma. We analyzed families with two or more cases of melanoma for germline mutations in CDKN2A and CDK4 to elucidate the contribution of these gene defects to familial malignant melanoma and to the occurrence of other cancer types.
Methods:
: The entire CDKN2A coding region and exon 2 of the CDK4 gene of an affected member of each of 52 families from southern Sweden with at least two cases of melanoma in first- or second-degree relatives were screened for mutations by use of polymerase chain reaction-single-strand conformation polymorphism analysis. Statistical tests were two-sided.
Results:
: CDKN2A mutations were found in 10 (19%) of the 52 families. Nine families carried an identical alteration consisting of the insertion of arginine at position 113 of p16(INK4a), and one carried a missense mutation, in which the valine at position 115 was replaced with a glycine. The 113insArg mutant p16(INK4a) was unable to bind cdk4 and cdk6 in an in vitro binding assay. Six of the 113insArg families had at least one member with multiple primary melanomas; the 113insArg families also had a high frequency of other malignancies-in particular, breast cancer (a total of eight cases compared with the expected 2.1; P =.0014) and pancreatic cancer (a total of six cases compared with the expected 0.16; P<.0001). Families with breast cancer also had a propensity for multiple melanomas in females, suggesting that a sex-dependent factor may modify the phenotypic expression of CDKN2A alterations.
Conclusions:
: Our findings confirm that the majority of CDKN2A-associated melanoma families in Sweden are due to a single founder mutation. They also show that families with the CDKN2A 113insArg mutation have an increased risk not only of multiple melanomas and pancreatic carcinoma but also of breast cancer.
Five to ten percent of individuals with melanoma have another affected family member, suggesting familial predisposition. Germ-line mutations in the cyclin-dependent kinase (CDK) inhibitor p16 have been reported in a subset of melanoma pedigrees, but their prevalence is unknown in more common cases of familial melanoma that do not involve large families with multiple affected members. We screened for germ-line mutations in p16 and in two other candidate melanoma genes, p19ARF and CDK4, in 33 consecutive patients treated for melanoma; these patients had at least one affected first or second degree relative (28 independent families). Five independent, definitive p16 mutations were detected (18%, 95% confidence interval: 6%, 37%), including one nonsense, one disease-associated missense, and three small deletions. No mutations were detected in CDK4. Disease-associated mutations in p19ARF, whose transcript is derived in part from an alternative codon reading frame of p16, were only detected in patients who also had mutations inactivating p16. We conclude that germ-line p16 mutations are present in a significant fraction of individuals who have melanoma and a positive family history.
The authors are grateful to the members of their laboratories for their contributions to the reviewed studies and for their critical reading of the manuscript and to F. Giardiello and S. Hamilton for photographs of colorectal lesions. The authors are supported by Public Health Service grants CA 43460, CA 57345, and CA 62924. B. V. is an Investigator of the Howard Hughes Medical Institute.
Approximately 10% of human cutaneous melanomas occur in families in which several members are affected. The familial predisposition to this disease is often associated with dysplastic nevus syndrome, a condition in which afflicted family members have multiple dysplastic nevi (atypical moles). The chromosome region 9p21 and markers on chromosomes 1p and 6p have been linked to melanoma susceptibility. The tumor suppressor genes CDKN2A and CDKN2B have been mapped to the 9p21 region, and genetic analyses have revealed the presence of germline CDKN2A alterations in melanoma families. The reported frequencies of such alterations, however, vary among these families.
The present investigation was carried out to determine the frequencies of CDKN2A and CDKN2B germline gene mutations among members in a population-based cohort of Swedish melanoma families (i.e., melanoma kindreds).
DNA was prepared from blood samples obtained from 181 individuals belonging to 100 melanoma kindreds. The polymerase chain reaction (PCR) technique, followed by single-strand conformation polymorphism (SSCP) and nucleotide sequence analyses, were used to identify the types and frequencies of mutations in exons 1, 1beta, 2, and 3 of the CDKN2A gene and in exons 1 and 2 of the CDKN2B gene.
CDKN2A gene aberrations were independently identified by both SSCP and nucleotide-sequence analyses. Nucleotide-sequence analysis identified a single point mutation leading to a substitution of leucine for proline in codon 48 of exon 1 in a family with a history of melanoma and several other cancers. A second abnormality, leading to an insertion of an extra arginine residue at codon number 113 of exon 2, was seen in four separate families. The CDKN2A exon-3 coding region had the wild-type sequence in all samples. No germline mutations were found in the alternative exon 1beta of the CDKN2A gene or in exons 1 and 2 of the CDKN2B gene.
The present investigation demonstrates that CDKN2A germline gene mutations were observed in 7.8% of the 64 Swedish melanoma kindreds that each included at least two first-degree relatives with melanoma and dysplastic nevus syndrome. No CDKN2A exon 1beta or CDKN2B mutations were identified. The critical genes responsible for the inheritance of a susceptibility to develop melanoma among family members in this population have yet to be identified.
Ninety-four H & E-stained slides of malignant melanoma were circulated to 6 pathologists in 2 university departments. For each slide, the growth phase of the lesion, Breslow thickness, and Clark level were determined by each observer. The aims of the study were to evaluate agreement between nonspecialist pathologists in identifying the vertical growth phase in malignant melanoma and to compare agreement for the growth phase with agreement for Breslow thickness and the Clark level. Our results show that although overall agreement for the growth phase is moderate, agreement between experienced observers is good. In fact agreement for the growth phase among this group was equal to the agreement for Breslow thickness. Overall agreement for Breslow thickness also was good but for the Clark level was only fair. These findings suggest that if the predictive value of the vertical growth phase proves to be robust, it will be used with an acceptable level of accuracy in routine diagnostic practice.
Many cases of hereditary breast cancer are due to mutations in either the BRCA1 or the BRCA2 gene. The histopathological changes in these cancers are often characteristic of the mutant gene. We hypothesized that the genes expressed by these two types of tumors are also distinctive, perhaps allowing us to identify cases of hereditary breast cancer on the basis of gene-expression profiles.
RNA from samples of primary tumor from seven carriers of the BRCA1 mutation, seven carriers of the BRCA2 mutation, and seven patients with sporadic cases of breast cancer was compared with a microarray of 6512 complementary DNA clones of 5361 genes. Statistical analyses were used to identify a set of genes that could distinguish the BRCA1 genotype from the BRCA2 genotype.
Permutation analysis of multivariate classification functions established that the gene-expression profiles of tumors with BRCA1 mutations, tumors with BRCA2 mutations, and sporadic tumors differed significantly from each other. An analysis of variance between the levels of gene expression and the genotype of the samples identified 176 genes that were differentially expressed in tumors with BRCA1 mutations and tumors with BRCA2 mutations. Given the known properties of some of the genes in this panel, our findings indicate that there are functional differences between breast tumors with BRCA1 mutations and those with BRCA2 mutations.
Significantly different groups of genes are expressed by breast cancers with BRCA1 mutations and breast cancers with BRCA2 mutations. Our results suggest that a heritable mutation influences the gene-expression profile of the cancer.
Background. According to the Knudson two-mutational-event theory, two mutations at a genetic locus may be required for the development of some cancers. Persons who have inherited a defect in one chromosome and therefore require only one more mutation for cancer development are at a higher risk of manifesting cancer at a younger age than persons without an inherited mutation, who need two acquired “hits.” This difference allows one to distinguish familial and sporadic types of the same malignancy by evaluating age of disease onset.Methods. To study the role of inheritance in the etiology of familial cutaneous melanoma, characteristics of patients with familial versus nonfamilial melanoma were analyzed according to the Knudson two-mutational-event model.Results. The familial versus nonfamilial graphs, based on age of diagnosis, did not support this model. However, there was a statistically significant earlier age of diagnosis for patients with familial melanoma. Melanoma thickness was less (i.e., earlier cancer at possibly younger age) for patients with a positive versus a negative family history. Conversely, linear regression, after adjusting for tumor thickness, showed that patients with hereditary melanoma still manifested earlier ages of diagnosis of melanoma compared with sporadic patients.Conclusions. Genetic patterns other than the two-step model, additional family-related factors, patient-physician sensitization due to a family history, or a combination of these factors might explain this age difference. More complex multistep modeling of the data may be helpful in better characterizing the genetic patterns of cutaneous melanoma.
In a combined analysis of 2952 melanoma patients and 3618 controls from 8 case-control studies in white populations the risk of cutaneous melanoma was 2.24-fold higher (95% Cl, 1.76–2.86) in subjects who reported at least one affected first-degree relative than in subjects who did not. There was no evidence for heterogeneity in the relative risk between the studies, which were from a wide range of latitudes and hence degrees of sun exposure. The effect of family history on melanoma risk was independent of age, naevus count, hair and eye colour, and freckling. There was no evidence for a relationship between family history and primary site of melanoma but there was some suggestion that the familial patients were more likely to have superficial spreading melanoma or lentigo maligna melanoma than acral lentiginous melanoma or nodular melanoma. © 1995 Wiley-Liss, Inc.
Germ-line mutations in the CDKN2A tumor-suppressor gene (also known as p16, p16INK4a, and MTS1) have been linked to the development of melanoma in some families with inherited melanoma. Whether mutations in CDKN2A confer a predisposition to sporadic (nonfamilial) melanoma is not known. In some patients with sporadic melanoma, one or more additional primary lesions develop, suggesting that some of these patients have an underlying genetic susceptibility to the cancer. We hypothesized that this predisposition might be due to germ-line CDKN2A mutations.
We used the polymerase chain reaction, single-strand conformation polymorphism analysis, and direct DNA sequencing to identify germ-line mutations in the CDKN2A gene in patients with multiple primary melanomas who did not have family histories of the disease. A quantitative yeast two-hybrid assay was used to evaluate the functional importance of the CDKN2A variants.
Of 33 patients with multiple primary melanomas, 5 (15 percent; 95 percent confidence interval, 4 percent to 27 percent) had germ-line CDKN2A mutations. These included a 24-bp insertion at the 5' end of the coding sequence, three missense mutations (Arg24Pro, Met53Ile, and Ser56Ile), and a 2-bp deletion at position 307 to 308 (resulting in a truncated CDKN2A protein). In three families, CDKN2A mutations identical to those in the probands were found in other family members. In two families with mutations, we uncovered previously unknown evidence of family histories of melanoma.
Some patients with multiple primary melanomas but without family histories of the disease have germ-line mutations of the CDKN2A gene. The presence of multiple primary melanomas may signal a genetic susceptibility to melanoma not only in the index patient but also in family members, who may benefit from melanoma-surveillance programs.
Linkage analysis of ten Utah kindreds and one Texas kindred with multiple cases of cutaneous malignant melanoma (CMM) provided evidence that a locus for familial melanoma susceptibility is in the chromosomal region 9p13-p22. The genetic markers analyzed reside in a candidate region on chromosome 9p21, previously implicated by the presence of homozygous deletions in melanoma tumors and by the presence of a germline deletion in an individual with eight independent melanomas. Multipoint linkage analysis was performed between the familial melanoma susceptibility locus (MLM) and two short tandem repeat markers, D9S126 and the interferon-alpha (IFNA) gene, which reside in the region of somatic loss in melanoma tumors. An analysis incorporating a partially penetrant dominant melanoma susceptibility locus places MLM near IFNA and D9S126 with a maximum location score of 12.71. Therefore, the region frequently deleted in melanoma tumors on 9p21 presumably contains a locus that plays a critical role in predisposition to familial melanoma.
Characteristics associated with familial compared with nonfamilial malignant melanoma were assessed. These data were obtained from consecutive prospectively completed questionnaires on 1169 cases of cutaneous malignant melanoma. Of these, 69 patients indicated a positive family history for this cancer. Among the various clinical and histological variables compared, those that significantly correlated with the familial occurrence of malignant melanoma include younger age at first diagnosis, smaller diameter of the lesion, lower Clark level, decreased frequency of nonmelanoma skin cancer, and reduced prevalence of noncutaneous cancer. Increased awareness of malignant melanoma among family members could account for some of these observations. Identification of the familial variety of malignant melanoma has practical implications concerning early detection and prompt intervention.
The dominantly inherited tumors of man demonstrate that mutation can be a step on the carcinogenetic pathway. Nonhereditary tumors may involve the same mutation in somatic cells rather than germ cells. In neither case is this mutation alone sufficient to produce a tumor, and evidence is presented that a second mutational step is required in the initiation process. Individuals who bear these mutations germinally are extremely susceptible to specific tumors, they may develop more than one tumor, and the average age at onset is earlier than usual. Recessive genes for cancer susceptibility and environmental carcinogens may interact with each other and with these dominant "cancer genes" to increase the probability that cancer mutations will occur.
Apart from the rare malignant melanomas occurring in blue nevi, primary cutaneous malignant melanoma arises in 1 of 3 ways, regardless of the presence or absence of a pre-existing nevus. These three types have been designated: 1. Malignant melanoma, invasive, with adjacent intra-epidermal component of Hutchinson's melanotic freckle type; 2. Malignant melanoma, invasive, with adjacent intra-epidermal component of superficial spreading type; and 3. Malignant melanoma, invasive, without adjacent intra-epidermal component. Occasionally, both clinically and histologically, there may be difficulty in deciding whether a malignant melanoma belongs to category 1 or 2, but, in the majority of cases, these 2 types can be quite readily distinguished. In addition to recording the histogenetic mode of development of a malignant melanoma, a histologic system of reporting is recommended which includes mitotic activity, levels of invasion, and vascular involvement. There are other parameters such as the cell type, pigmentation, lymphocytic infiltrates, evidence of spontaneous regression, associated nevi, and solar changes in the dermis, all of which are of unknown significance. The recording of these features, which are clearly of interest for research purposes, is left to individual discretion. It is emphasized that all the usual macroscopic descriptions and measurements should continue to be recorded.
Inter-observer variation between six pathologists in their application of histological classifications during a survey of cutaneous malignant melanoma was analysed using kappa statistics. The highest levels of adjusted agreement were attained for tumour thickness and the presence of ulceration; intermediate levels were achieved on cross-sectional profile, level of invasion, histogenetic type, solar elastosis and the presence of an associated benign melanocytic lesion; agreement on other histological features of melanoma tended to be relatively poor. The problems experienced in the interpretation of these classifications are discussed and suggestions for their improvement are offered.
Computer analyses to identify correlations between thickness of primary superficial spreading malignant melanoma and eighteen variables previously reported to be related to prognosis were performed on a series of malignant melanomas. The variables that showed statistically significant (less than or equal to 0.05) direct relationships to thickness were level (Clark), elevation of lesion, age of patient, least and greatest diameters of lesion, history of bleeding, ulceration, clinical and histologic stage, anatomic location, pedunculation, and satellitosis. The variables that did not correlate with thickness were clinical diagnosis of regional lymphadenopathy, in-transit metastasis, duration of lesion, sex, history of a previous malignant melanoma, and history of a pre-existing lesion at the site of the development of melanoma. Multiple regression analysis of the factors that showed statistically significant correlation with thickness of the primary lesion revealed a subset of six dominant variables that were most predictive of thickness, namely, level, elevation, largest diameter of lesion, ulceration, histologic stage, and age of the patient.
To evaluate the variations within and between observers in the interpretation of important histological prognostic factors, a series of 96 melanoma patients was randomly selected from a database of 1691 patients with cutaneous malignant melanoma. The stained sections were examined on two occasions by four experienced pathologists. Analysis by observed agreement and kappa statistics showed maximal tumour thickness to be the best reproducible variable, with ulceration the second best. Regression was the least reproducible, with level of invasion and type of melanoma in the mid range. Intra-observer variation was uniformly less than inter-observer variation for each variable. For tumour thickness a variance component analysis was done to quantify the variability further. The clinician should not base his choice of treatment entirely on the microscopic classification but take into consideration the clinical course and appearance of the tumour.
Five percent to 10% of cutaneous malignant melanomas (CMMs) occur in a familial setting. Clinical, epidemiologic, and genetic studies of familial CMM in different regions of the world have led to various results. To assess the characteristics of familial CMM in France, the clinical, histologic, and epidemiologic characteristics of 295 patients with CMM were recorded, and a comprehensive familial investigation was performed for each case. Patients with a family history of CMM were compared with nonfamilial cases.
Cutaneous malignant melanoma occurred as a familial cancer in 22 (8%) of 295 patients. Among the multiple variables studied, those significantly associated with the familial occurrence of CMM were red hair, inability to tan, and presence of clinically atypical moles. When these variables were considered together in a multivariate analysis, only the association with red hair (P = .001) and atypical moles (P < .05) remained significant. In addition, the patients with familial melanoma exhibited the following tendencies: a younger age at diagnosis, a higher number of moles, and the development of multiple primary melanomas, but these results did not reach statistical significance. Factors relating to UV light exposure, histologic features of CMM, course of the disease, and occurrence of nonmelanoma cancers showed a similar distribution between familial and nonfamilial cases.
A familial investigation should be performed for each patient with CMM in France, particularly when he or she exhibits phenotypic risk factors for CMM such as red hair and atypical moles.
Extremity location and female gender are both considered favourable prognostic parameters in primary melanoma, but since they cluster in the same group of patients, the question remains as to whether they are both independent variables. Multivariate analysis of 695 patients with primary, localised melanoma was used. The effects of gender and anatomical location were compared directly by sequentially controlling one factor while the other remained free. Following multivariate analysis, significant prognostic factors related to survival were the thickness of the primary lesion (P < 0.0001), the age of the patient at diagnosis (P < 0.0001), the gender of the patient (P = 0.0008) and the anatomical location of the primary lesion (P = 0.005). Thicker lesions, patients older than 50 years, males, and trunk, head and neck locations had poorer prognoses. There was a significant difference in survival according to gender within each location, extremity (P = 0.002) or trunk, head and neck (P = 0.0004); however, there was no significant difference in survival according to anatomical location within each gender, male (P = 0.11) or female (P = 0.29). The thickness of the primary lesion, the age of the patient at diagnosis, the gender and the anatomical location of the melanoma are all significant prognostic parameters in localised melanoma. Gender appears to have a more pronounced effect on survival than anatomical location.
The overall incidence of melanoma is increasing world wide. We investigated whether there has been an increase in familial melanoma by studying age at onset among different birth cohorts in 18 melanoma kindreds linked to a predisposition gene (MLM2) on chromosome 9. The cumulative incidence of melanoma was 21-fold higher (95% CI 5.2-84.6) among subjects born after 1959 than in those born before 1900. The expected age of onset of the group born after 1959 was 24 years earlier (21.0 vs 45.0 years). These data support the notion that phenotypic penetrance of the MLM2 gene is increasing, presumably as a result of the interaction of sunlight exposure and mutation at this locus.
The p16 gene is located in chromosome 9p21, a region that is linked to familial melanoma and homozygously deleted in many tumour cell lines. We describe eight p16 germline substitutions (one nonsense, one splice donor site and six missense) in 13/18 familial melanoma kindreds. Six of these mutations were identified in 33/36 melanoma cases in nine families, whereas two were detected in normal controls and are not disease-related. The melanoma-specific mutations were detected in 9p21-linked, but not in 1p36-linked, families, thereby confirming previous reports of genetic heterogeneity. Functional analyses of these mutations will confirm those causally related to the development of familial melanoma.
Familial melanoma patients tend to have an earlier age at first melanoma diagnosis, thinner lesions, a different histologic distribution, and a higher frequency of multiple primary melanomas than patients with nonfamilial melanoma. Previous examination of a large melanoma kindred from Texas suggested that although cutaneous malignant melanoma (CMM) was transmitted in an autosomal dominant fashion, there were sex differences in penetrance and disease expression.
This study further evaluated the age at diagnosis, sex difference in penetrance and disease expression, and segregation of familial CMM.
We evaluated the age at diagnosis and transmission of CMM in 23 U.S. white families with CMM/dysplastic nevi who had been followed 5-17 years. We estimated the median and mean ages at diagnosis of invasive melanoma for all individuals, for men and women separately, and by generation. Using the computer program BMDP1L, we also estimated the cumulative probability of an offspring developing CMM as a function of age according to whether the mother or father had melanoma. In addition, we used a life-table approach to estimate the probability that offspring of CMM parents were affected with CMM (penetrance).
The median age at diagnosis in the 23 kindreds (n = 106) was 33 years, substantially less than that of patients with sporadic melanomas in the U.S. white population. For females, the median age at diagnosis was 29 years; for males, it was 36 years. Nine percent of the case patients developed CMM before age 20 compared with 2% in the general population. There was little difference in the transmission pattern of melanoma between males and females in the 23 families, although sons of CMM parents had a higher risk of CMM than daughters of CMM parents. This difference was, however, based on small numbers and was not statistically significant. The penetrance estimates for CMM were high. They rose rapidly from 6% at age 18 to 85% by age 48. The median age at diagnosis of invasive melanoma decreased dramatically in successive generations; the reduction was 11-16 years per generation and was statistically significant (P < .0001).
Although this reduction in median age at diagnosis may result partly from increased surveillance in hereditary melanoma families and the fact that individuals in the younger generations have not yet reached the highest at-risk ages for developing melanoma, the possibility of changes in melanoma risk and risk factors, genetic and/or environmental, across generations should be considered.
We examined the relationship between cutaneous malignant melanoma/dysplastic nevi (CMM/DN) and chromosome 9p in 13 pedigrees with two or more living cases of invasive melanoma. We used two highly informative (CA)n repeats, D9S126 and IFNA, previously implicated in familial malignant melanoma (MLM), to conduct linkage analysis. Three analyses were performed: (1) CMM alone--all individuals without either confirmed melanoma or borderline lesions were considered unaffected (model A); (2) CMM/DN with both variable age at onset and sporadics (model B); and (3) CMM affecteds only--all individuals either without confirmed melanoma or with borderline lesions were designated "unknown" (model C). There was significant evidence for linkage to IFNA in all three models. For CMM alone, the maximum lod score (Zmax) was 4.36 at theta = .10 for model A and 3.39 at theta = .10 for model C. For CMM/DN (model B), Zmax = 3.05 at theta = .20. There was no significant evidence for linkage between CMM alone or CMM/DN and chromosome 9p marker D9S126. In addition, there was significant evidence for heterogeneity when a homogeneity test allowing for linkage to chromosome 9p or chromosome 1p or neither region was used. These results suggest that there is an MLM susceptibility locus on chromosome 9p but that familial melanoma is heterogeneous and not all families with CMM/DN are linked to a locus in this region.
A putative tumor suppressor locus on the short arm of human chromosome 9 has been localized to a region of less than 40 kilobases
by means of homozygous deletions in melanoma cell lines. This region contained a gene, Multiple Tumor Suppressor 1 (MTS1),
that encodes a previously identified inhibitor (p16) of cyclin-dependent kinase 4. MTS1 was homozygously deleted at high frequency
in cell lines derived from tumors of lung, breast, brain, bone, skin, bladder, kidney, ovary, and lymphocyte. Melanoma cell
lines that carried at least one copy of MTS1 frequently carried nonsense, missense, or frameshift mutations in the gene. These
findings suggest that MTS1 mutations are involved in tumor formation in a wide range of tissues.
Malignant melanoma occurs as a familial cancer in 5%-10% of cases where it segregates in a manner consistent with autosomal dominant inheritance. Evidence from cytogenetics, fine-mapping studies of deletions in melanomas, and recent linkage studies supports the location of a human melanoma predisposition gene on the short arm of chromosome 9. We have carried out linkage analysis using the 9p markers IFNA and D9S126 in 26 Australian melanoma kindreds. Multipoint analysis gave a peak lod score of 4.43, 15 cM centromeric to D9S126, although a lod score of 4.13 was also found 15 cM telomeric of IFNA. These data confirm the existence of a melanoma susceptibility gene on 9p and indicate that this locus most probably lies outside of the IFNA-D9S126 interval. No significant heterogeneity was found between families, when either pairwise or multipoint data were analyzed using HOMOG.
According to the Knudson two-mutational-event theory, two mutations at a genetic locus may be required for the development of some cancers. Persons who have inherited a defect in one chromosome and therefore require only one more mutation for cancer development are at a higher risk of manifesting cancer at a younger age than persons without an inherited mutation, who need two acquired "hits." This difference allows one to distinguish familial and sporadic types of the same malignancy by evaluating age of disease onset.
To study the role of inheritance in the etiology of familial cutaneous melanoma, characteristics of patients with familial versus nonfamilial melanoma were analyzed according to the Knudson two-mutational-event model.
The familial versus nonfamilial graphs, based on age of diagnosis, did not support this model. However, there was a statistically significant earlier age of diagnosis for patients with familial melanoma. Melanoma thickness was less (i.e., earlier cancer at possibly younger age) for patients with a positive versus a negative family history. Conversely, linear regression, after adjusting for tumor thickness, showed that patients with hereditary melanoma still manifested earlier ages of diagnosis of melanoma compared with sporadic patients.
Genetic patterns other than the two-step model, additional family-related factors, patient-physician sensitization due to a family history, or a combination of these factors might explain this age difference. More complex multistep modeling of the data may be helpful in better characterizing the genetic patterns of cutaneous melanoma.
Family history is an important risk factor for cutaneous malignant melanoma. We evaluated the clinical characteristics of patients with cutaneous familial melanoma. A chart review was conducted, including all patients who presented to Massachusetts General Hospital Pigmented Lesion Clinic over an 8-year period. A total of 102 patients from 49 families were confirmed with shaving cutaneous melanoma. Eighty-two per cent had a personal and/or family history of dysplastic naevi. Within families, subsequent affected patients had thinner primary lesions with substantially lower median thickness than those diagnosed first. Seventeen per cent had multiple primary melanomas, with the median thickness of subsequent primaries being much lower than that of the first primary lesions. The mean thickness of primary lesions in patients with one primary lesion was marginally significantly greater than that in patients with multiple primaries. Verification of family history is essential given the implications of a positive family history. Screening family members of all patients with cutaneous melanoma and surveillance examinations for all patients with cutaneous melanoma is recommended.
To assess the interobserver agreement on the diagnosis and classification of cutaneous melanoma.
A set of 140 slides of cutaneous melanoma, including a small subset of benign pigmented skin lesions, were circulated to four experienced histopathologists. The kappa statistic for multiple ratings per subject was calculated using the method described by Fleiss.
The kappa value on the diagnosis of cutaneous melanoma versus benign lesions was 0.61. There was some discordance on the diagnosis in 37 of 140 cases (26%). For the histopathologic classification of cutaneous melanoma, the highest kappa values were attained for Breslow thickness (kappa = 0.76) and presence of ulceration (kappa = 0.87). The agreement was generally poor for other histologic features, such as level of dermal invasion (kappa = 0.38), presence of regression (kappa = 0.27), and lymphocytic infiltration (kappa = 0.27).
Our study suggests considerable disagreement among pathologists on the diagnosis of melanoma versus other pigmented lesions. Tumor thickness and presence of ulceration are the most reproducible histologic features of cutaneous melanoma.
There is a worldwide increase in the incidence of cutaneous malignant melanoma (CMM) among whites. In Sweden, a five-fold increase has been recorded since 1960, although the increase in mortality rate is substantially lower. Tumor thickness is recognized as the most important histologic prognostic factor for primary melanoma. In a previous study, the authors did not find any significant decrease in mean tumor thickness over the period 1965-1985 in their region. In the current study, prognostic factors for melanoma were evaluated for this time period.
In a population-based study, 468 cases of invasive melanoma, diagnosed in the years 1965, 1975, and 1985, were histopathologically reexamined. The level of invasion, tumor thickness, regressive reaction, ulceration, presence of inflammatory cells, presence of benign nevus cells, and site of presentation were studied. In 461 of these 468 patients, it was possible to correlate the histopathologic factors with survival.
In univariate analyses, the parameters of presence of ulceration, increasing tumor thickness, male gender, nodular type of melanoma, and older age at diagnosis were significantly related to a shortened overall survival. In various multivariate models with adjustment for age and the factors studied simultaneously, ulceration, increasing tumor thickness, and male gender were significantly associated with a poor prognosis. Correlations between the factors studied were noted. It was observed that older patients tended to have thicker tumors. Thick melanomas correlated to a deeper level of invasion (Clark's), nodular growth pattern, ulceration, less inflammation, and less regression compared with thin, less invasive melanomas. Women had significantly fewer inflammatory cells and fewer signs of regression in their tumors compared with men.
In multivariate analyses adjusted for age, increasing tumor thickness, older age, ulceration, and male gender were significantly associated with a poor prognosis among patients with invasive CMM. None of these factors showed a significant change for the years 1965, 1975, and 1985. Thus, a change in the prognostic factors studied does not explain the increased survival of melanoma patients for this time period.
BRCA1 mutations, although implicated in disease predisposition in a major part of the hereditary breast cancer population, do not seem to be crucially involved in tumorigenesis of sporadic breast and ovarian cancers. This suggests that tumours arising in BRCA1 mutation carriers may differ from BRCA1 negative hereditary and sporadic cancer in genetic and biological features, as well as in clinical behaviour. Prior to BRCA1 analysis, 79 breast and 19 ovarian tumours from 57 breast and breast-ovarian cancer families, and 170 tumours from a comparison group of stage II breast cancers were studied with regard to histopathological features; immunohistochemistry [c-erbB-2, p53, oestrogen receptor (ER) and progesterone receptor (PR)], DNA flow cytometry and S-phase fraction. BRCA1 mutations were found in 40 breast and 15 ovarian tumours. The BRCA1 positive breast tumours were significantly more often of ductal type, histological grade III and manifested a heavy lymphocyte infiltration. Additionally, as compared to BRCA1 negative tumours, the BRCA1 positive tumours were significantly more often ER, PgR and c-erbB-2 negative. Furthermore, they were significantly more often DNA non-diploid, as well as being characterised by higher S-phase fraction values. These results suggest that BRCA1-induced breast cancers may manifest distinct tumour biological features of clinical importance.
We report six of 16 U.K. melanoma families and two of 17 patients with multiple primary melanomas and a negative family history who have between them four different functionally damaging mutations of the CDKN2A (p16) gene: an Arg 24 Pro substitution in exon 1 in one family, a stop codon at codon 44 of exon 1 in one family, and a Met 53 Ile substitution in exon 2 in four families. One multiple primary melanoma patient also has the Met 53 Ile mutation and a second has a G-T substitution at the IVS2 + 1 splice donor site. Our data together with other recent publications from France and the U.S.A. indicate that screening melanoma kindreds with only two affected family members for CDKN2A mutations is justified.
In this population-based, case-control study from Sweden using data collected from 1988 to 1990, an increased risk of melanoma was associated with the number of sunburns, propensity to freckle, the number of raised naevi and a family history of melanoma. Furthermore, a decreased risk was associated with occupational sun exposure. The purpose of this study was to investigate whether different histopathological features of the melanoma and clinical factors were related to the different aetiological risk factor patterns. All the confirmed primary cutaneous melanomas (n = 366) were included in the study. Both univariate analyses with tests for interaction and multivariate analyses were performed. Patients with melanoma on the trunk and patients with thin melanomas had an excess of close relatives with a history of melanoma (odds ratios [ORs] = 2.7 and 2.3, respectively). A relationship was also seen between melanomas in younger persons and a family history of melanoma (OR = 2.6). The presence of raised naevi on the arm had a tendency to be closer related to melanoma of the nodular type (OR = 4.3) than melanoma of the superficial spreading type (OR = 1.6). Patients with outdoor occupations during summer had a decreased risk of developing melanoma on the extremities. Melanoma diagnosed in patients born before 1939 had an association with sunburns (OR = 1.9) and freckling (OR = 2.0), while melanomas in patients born in 1939 or later were related to a family history of melanoma (OR = 2.2). These results suggest that different histopathological and clinical features of melanoma are associated with different risk factor patterns, which may imply diverging tumour genesis.
A population-based study from Sweden identified 711 patients with cutaneous malignant melanoma diagnosed in 1965, 1975, 1985 and 1989. Prognostic factors were evaluated and a review of the literature was performed. On univariate analysis, thick tumours (> 0.8 mm) (odds ratio [OR] 1.8, 95% confidence interval [CI] 1.6-2.1), increasing Clark level (OR 1.8, 95% CI 1.6-2.0), ulceration (OR 1.8, 95% CI 1.6-2.0), nodular melanoma (OR 1.5, 95% CI 1.3-1.6) and increasing age (continuous variable, P < 0.0001) were associated with a shorter survival. Location on extremities (OR 0.8, 95% CI 0.7-0.9), inflammation (OR 0.8, 95% CI 0.7-0.9) and female gender (OR 0.8, 95% CI 0.8-0.9) were associated with improved survival. On multivariate analysis, thick tumours (> 0.8 mm) (OR 1.5, 95% CI 1.2-1.7) and ulceration (OR 1.4, 95% CI 1.2-1.6) were independently related to a poor prognosis, while location on extremities (OR 0.8, 95% CI 0.7-0.9), inflammation (OR 0.8, 95% CI 0.7-0.9) and female gender (OR 0.8, 95% CI 0.8-1.0) were associated with improved survival. No difference in mean tumour thickness was seen over time, but there was a significant increase in the percentage of thin melanomas (< 0.8 mm) in 1985 (P = 0.01) and 1989 (P = 0.002) compared with 1965. The incidence of melanomas with inflammation increased significantly (P = 0.04), as did age at diagnosis (P = 0.005).