[Show abstract][Hide abstract] ABSTRACT: Many suspected Lynch Syndrome (sLS) patients who lack mismatch repair (MMR) germline gene variants and MLH1 or MSH2 hypermethylation are currently explained by somatic MMR gene variants or, occasionally, by germline POLE variants. To further investigate unexplained sLS patients, we analyzed leukocyte and tumor DNA of 62 sLS patients using gene panel sequencing including the POLE, POLD1 and MMR genes. Forty tumors showed either one, two or more somatic MMR variants predicted to affect function. Nine sLS tumors showed a likely ultramutated phenotype and were found to carry germline (n=2) or somatic variants (n=7) in the POLE/POLD1 exonuclease domain (EDM). Six of these POLE/POLD1-EDM mutated tumors also carried somatic MMR variants. Our findings suggest that faulty proofreading may result in loss of MMR and thereby in microsatellite instability.European Journal of Human Genetics advance online publication, 9 December 2015; doi:10.1038/ejhg.2015.252.
Preview · Article · Dec 2015 · European journal of human genetics: EJHG
[Show abstract][Hide abstract] ABSTRACT: Background:
The risk to develop colorectal and endometrial cancers among subjects testing positive for a pathogenic Lynch syndrome mutation varies, making the risk prediction difficult. Genetic risk modifiers alter the risk conferred by inherited Lynch syndrome mutations, and their identification can improve genetic counseling. We aimed at identifying rare genetic modifiers of the risk of Lynch syndrome endometrial cancer.
A family based approach was used to assess the presence of genetic risk modifiers among 35 Lynch syndrome mutation carriers having either a poor clinical phenotype (early age of endometrial cancer diagnosis or multiple cancers) or a neutral clinical phenotype. Putative genetic risk modifiers were identified by Next Generation Sequencing among a panel of 154 genes involved in endometrial physiology and carcinogenesis.
A simple pipeline, based on an allele frequency lower than 0.001 and on predicted non-conservative amino-acid substitutions returned 54 variants that were considered putative risk modifiers. The presence of two or more risk modifying variants in women carrying a pathogenic Lynch syndrome mutation was associated with a poor clinical phenotype.
A gene-panel is proposed that comprehends genes that can carry variants with putative modifying effects on the risk of Lynch syndrome endometrial cancer. Validation in further studies is warranted before considering the possible use of this tool in genetic counseling.
[Show abstract][Hide abstract] ABSTRACT: Background: BRCA1 and BRCA2 mutation carriers are at substantially increased risk for developing breast and ovarian cancer. The incomplete penetrance coupled with the variable age at diagnosis in carriers of the same mutation suggests the existence of genetic and non-genetic modifying factors. In this study we evaluated the putative role of variants in many candidate modifier genes. Methods: Genotyping data from 15,252 BRCA1 and 8,211 BRCA2 mutation carriers, for known variants (n=3,248) located within or around 445 candidate genes, were available through the iCOGS custom-designed array. Breast and ovarian cancer association analysis was performed within a retrospective cohort approach. Results: The observed p-values of association ranged between 0.005-1.000. None of the variants was significantly associated with breast or ovarian cancer risk in either BRCA1 or BRCA2 mutation carriers, after multiple testing adjustments. Conclusion: There is little evidence that any of the evaluated candidate variants act as modifiers of breast and/or ovarian cancer risk in BRCA1 or BRCA2 mutation carriers. Impact: Genome-wide association studies have been more successful at identifying genetic modifiers of BRCA1/2 penetrance than candidate gene studies.
No preview · Article · Oct 2014 · Cancer Epidemiology Biomarkers & Prevention
[Show abstract][Hide abstract] ABSTRACT: Background:We aimed to quantify previously observed relatively high cancer risks in BRCA2 mutation carriers (BRCA2 carriers) over 60 in the Northern Netherlands, and to analyze whether these could be explained by mutation spectrum or population background risk. Methods:This consecutive cohort study included all known pathogenic BRCA1/2 carriers in the Northern Netherlands (N = 1,050). Carrier and general reference populations were: BRCA1/2 carriers in the rest of the Netherlands (N = 2,013) and the general population in both regions. Regional differences were assessed with hazard ratios (HRs) and odds ratios (ORs). HRs were adjusted for birth year and mutation spectrum. Results:All BRCA1 carriers and BRCA2 carriers under age 60 had a significantly lower breast cancer risk in the Northern Netherlands, HRs were 0.66 and 0.64, respectively. Above age 60, the breast cancer risk in BRCA2 carriers in the Northern Netherlands was higher than in the rest of the Netherlands (HR = 3.99, 95% CI 1.11-14.35). Adjustment for mutational spectrum changed the HRs for BRCA1, BRCA2 <60 and BRCA2 ≥60 years by -3%, +32% and +11% to 0.75, 0.50 and 2.61, respectively. There was no difference in background breast cancer incidence between the two regions (OR = 1.03, 95% CI 0.97-1.09). Conclusions:Differences in mutation spectrum only partly explain the regional differences in breast cancer risk in BRCA2 carriers, and for an even smaller part in BRCA1 carriers. Impact:The increased risk in BRCA2 carriers over 60 may warrant extension of intensive breast screening beyond age 60.
No preview · Article · Aug 2014 · Cancer Epidemiology Biomarkers & Prevention
[Show abstract][Hide abstract] ABSTRACT: Women carrying a Lynch Syndrome (LS) mutation have increased lifetime risk to develop - among others - endometrial cancer (EC). LS mutations can occur in four different mismatch-repair (MMR) genes and screening of these genes in currently used for genetic counselling. However, cancer risk predictions are broad and inaccurate and some woman carrying one given mutation can develop EC some other not.
We hypothesised that EC risk is modified by additional germ-line variants besides the MMR gene mutations.
To identify novel germ-line variants, the peripheral blood DNA from 38 EC patients belonging to LS families was analysed by targeted sequencing. Per patient, 154 genes involved in endometrial carcinogenesis were captured (Agilent® Haloplex™ capture system) and subjected to massive parallel sequencing using Illumina® HiSeq™. Raw data were analysed with Softgenetics ® NEXTgene ™ and Agilent ® SureCall ™. The panel of 154 genes included genes involved in estrogen metabolism and signalling, besides onco- and tumour-suppressors
After excluding common variants and synonymous mutations, two protein-coding variants per patient were identified, corresponding to a mutation rate of 3.9/MB. Genes like APC, MLL, LEPR and NOTCH1 carried distinct mutations in 10% of the patients. In addition, genes involved in estrogen metabolism and signalling (CYP1A1, CYP19A1, COMT, NCOR1, NCOR2, NCOA2, STS) resulted mutated in 40% of the patients analysed. Extra genes where mutations occurred frequently were identified (RET, ATM). The tumour material of these patients is being currently analysed for loss-of-heterozygosity, for protein aberration, inactivation or overexpression analyses.
In conclusions, additional germ-line mutations can modify the EC risk of a MMR LS mutation. The high prevalence of these mutations in specific genes/pathways can be used for a better cancer risk prediction by analysing these genes in routine genetic testing of LS family members.
[Show abstract][Hide abstract] ABSTRACT: Pilot study to evaluate whether the use of a standardized questionnaire to document family history of cancer improves identification of women who warrant referral to cancer genetic services (CGS) for increased risk of hereditary cancer, compared to their identification in usual care. Prospective intervention study with historic control group. Gynecology outpatient clinic, Maastricht University Medical Centre, the Netherlands. The prospective intervention group consisted of new outpatients between June 1 and August 1, 2011. The historic control group consisted of new outpatients between May 1, 2009 and April 30, 2010. A standardized questionnaire based on established referral criteria for hereditary breast/ovarian cancer and Lynch syndrome was completed for the intervention group. The referral rate in routine consultation, based on non-standardized family history recording, was determined retrospectively for the control group. The difference in referral rate between intervention and control group, tested by Chi square test. In the control group, 8 of 3,036 women (0.26 %) were referred to CGS. In the intervention group, 209 (42 %) of 500 screening questionnaires were completed. Nineteen women (9, 1 %) met the referral guidelines, of which 5 were newly referred to CGS (2, 4 %). Referral rates differed significantly (p < 0.001) between the two groups. This pilot study shows that the routine use of a screening questionnaire may improve detection and referral rate to CGS of individuals at risk for hereditary cancer. Improving genetic literacy of physicians and use of web-site questionnaires deserve attention in future studies.
[Show abstract][Hide abstract] ABSTRACT: How do couples with a BRCA1/2 mutation decide on preimplantation genetic diagnosis (PGD) and prenatal diagnosis (PND) for hereditary breast and ovarian cancer syndrome (HBOC)?
BRCA couples primarily classify PGD and/or PND as reproductive options based on the perceived severity of HBOC and moral considerations, and consequently weigh the few important advantages of PGD against numerous smaller disadvantages.
Awareness of PGD is generally low among persons at high risk for hereditary cancers. Most persons with HBOC are in favour of offering PGD for BRCA1/2 mutations, although only a minority would consider this option for themselves. Studies exploring the motivations for using or refraining from PGD among well-informed BRCA carriers of reproductive age are lacking. We studied the reproductive decision-making process by interviewing a group of well-informed, reproductive aged couples carrying a BRCA1/2 mutation, regarding their decisional motives and considerations.
This exploratory, qualitative study investigated the motives and considerations taken into account by couples with a BRCA1/2 mutation and who have received extensive counselling on PGD and PND and have made a well-informed decision regarding this option. Eighteen couples took part in focus group and dyadic interviews between January and September 2012.
Semi-structured focus groups were conducted containing two to four couples, assembled based on the reproductive method the couple had chosen: PGD (n = 6 couples) or conception without testing (n = 8 couples). Couples who had chosen PND for BRCA (n = 4) were interviewed dyadically. Two of the women, of whom one had chosen PND and the other had chosen no testing, had a history of breast cancer.
None of the couples who opted for PGD or conception without testing found the use of PND, with possible pregnancy termination, acceptable. PND users chose this method because of decisive, mainly practical reasons (natural conception, high chance of favourable outcome). Motives and considerations regarding PGD largely overlapped between PGD users, PND users and non-users, all mentioning some significant advantages (e.g. protecting the child and family from the mutation) and many smaller disadvantages (e.g. the necessity of in vitro fertilization (IVF), low chance of pregnancy by IVF/PGD). For female carriers, the safety of hormonal stimulation and the time required for PGD before undergoing preventive surgeries were important factors in the decision. Non-users expressed doubts about the moral justness of their decision afterwards and emphasized the impact the decision still had on their lives.
The interviewed couples were at different stages in their chosen trajectory, up to 3 years after completion. This may have led to recall bias of original motives and considerations. Couples who did not actively seek information about PGD were excluded. Therefore the results may not be readily generalizable to all BRCA couples.
The perceived severity of HBOC and, for female carriers, the safety of hormonal stimulation and the time frames for PGD planning before preventive surgeries are essential items BRCA couples consider in reproductive decision-making. The emotional impact of this decision should not be underestimated; especially non-users may experience feelings of doubt or guilt up to several years afterwards. PGD counselling with tailored information addressing these items and decisional support in order to guarantee well-informed decision-making is needed.
This study was funded by the Dutch breast cancer foundation Stichting Pink Ribbon, grant number 2010.PS11.C74. None of the authors have competing interests to declare.
[Show abstract][Hide abstract] ABSTRACT: Preimplantation Genetic Diagnosis (PGD) is a method of testing in vitro embryos as an alternative to prenatal diagnosis with possible termination of pregnancy in case of an affected child. Recently, PGD for hereditary breast and ovarian cancer caused by BRCA1 and BRCA2 mutations has found its way in specialized labs. We describe the route to universal single-cell PGD tests for carriers of BRCA1/2 mutations. Originally, mutation-specific protocols with one or two markers were set up and changed when new couples were not informative. This route of changing protocols was finalized after 2 years with universal tests for both BRCA1 and BRCA2 mutation carriers based on haplotyping of, respectively, 6 (BRCA1) and 8 (BRCA2) microsatellite markers in a multiplex PCR. Using all protocols, 30 couples had a total of 47 PGD cycles performed. Eight cycles were cancelled upon IVF treatment due to hypostimulation. Of the remaining 39 cycles, a total of 261 embryos were biopsied and a genetic diagnosis was obtained in 244 (93%). In 34 of the 39 cycles (84.6%), an embryo transfer was possible and resulted in 8 pregnancies leading to a fetal heart beat per oocyte retrieval of 20.5% and a fetal heart beat per embryonic transfer of 23.5%. The preparation time and costs for set-up and validation of tests are minimized. The informativity of microsatellite markers used in the universal PGD-PCR tests is based on CEPH and deCODE pedigrees, making the tests applicable in 90% of couples coming from these populations.European Journal of Human Genetics advance online publication, 27 March 2013; doi:10.1038/ejhg.2013.50.
Full-text · Article · Mar 2013 · European journal of human genetics: EJHG
[Show abstract][Hide abstract] ABSTRACT: Pheochromocytomas (PCC) and paragangliomas (PGL) are genetically heterogeneous neural crest-derived neoplasms. Recently we identified germline mutations in a new tumor suppressor susceptibility gene, MAX (MYC-associated factor X), which predisposes carriers to PCC. How MAX mutations contribute to PCC/PGL and associated phenotypes remain unclear. This study aimed to examine the prevalence and associated phenotypic features of germline and somatic MAX mutations in PCC/PGL. Design: We sequenced MAX in 1,694 patients with PCC or PGL (without mutations in other major susceptibility genes) from 17 independent referral centers. We screened for large deletions/duplications in 1,535 patients using a multiplex PCR-based method. Somatic mutations were searched for in tumors from an additional 245 patients. The frequency and type of MAX mutation was assessed overall and by clinical characteristics.
Sixteen MAX pathogenic mutations were identified in 23 index patients. All had adrenal tumors, including 13 bilateral or multiple PCCs within the same gland (P < 0.001), 15.8% developed additional tumors at thoracoabdominal sites, and 37% had familial antecedents. Age at diagnosis was lower (P = 0.001) in MAX mutation carriers compared with nonmutated cases. Two patients (10.5%) developed metastatic disease. A mutation affecting MAX was found in five tumors, four of them confirmed as somatic (1.65%). MAX tumors were characterized by substantial increases in normetanephrine, associated with normal or minor increases in metanephrine.
Germline mutations in MAX are responsible for 1.12% of PCC/PGL in patients without evidence of other known mutations and should be considered in the genetic work-up of these patients.
Full-text · Article · Mar 2012 · Clinical Cancer Research
[Show abstract][Hide abstract] ABSTRACT: Despite extensive analysis of the BRCA1 and BRCA2 genes, germline mutations are detected in <20% of families with a presumed genetic predisposition for breast and ovarian cancer. Recent literature reported RAD51C as a new breast cancer susceptibility gene. In this study, we report the analysis of 410 patients from 351 unrelated pedigrees. All were referred for genetic testing and we selected families with at least one reported case of ovarian cancer in which BRCA1&2 mutations were previously ruled out. We analyzed the coding exons, intron-exons boundaries, and UTRs of RAD51C. Our mutation analysis did not reveal any unequivocal deleterious mutation. In total 12 unique sequence variations were identified of which two were novel. Our study and others suggest a low prevalence of RAD51C mutations with an exception for some founder populations. This observation is in favor of the rare allele hypothesis in the debate over the nature of the genetic contribution to individual susceptibility to breast and ovarian cancer and further genome-wide studies in high risk families are warranted.
No preview · Article · Feb 2012 · Breast Cancer Research and Treatment
[Show abstract][Hide abstract] ABSTRACT: It has been hypothesized that the Outcomes of DNA testing (O) are better predicted and/or mediated by the counselees' Perception P) than by the actually communicated genetic Information (I). In this study, we aimed at quantifying the effect that perception has in genetic counseling for hereditary breast/ovarian cancer.
Two hundred and four women, who had previously been tested for BRCA1/2, participated in a retrospective questionnaire study; 93% had cancer. Communicated Information (I) consisted of cancer risks and BRCA1/2 test result category: unclassified variant (n = 76), uninformative (n = 76), pathogenic mutation (n = 51). Four perception variables (P) were included: the counselees' recollections and interpretations of both the cancer risks and the likelihood that the cancer in their family is heritable. The Outcome variables (O) included life changes, counselees' medical decisions, BRCA-related self-concept, current psychological well-being, and quality-of-life. Bootstrap mediation analyses determined whether relationships were direct (I→O or P→O) or indirect through the mediation of perception (I→P→O).
The actually communicated pathogenic mutation and uninformative result directly predicted medical decisions (I→O), i.e. intended and performed surgery of breasts/ovaries. All other outcomes were only directly predicted by the counselees' perception (recollection and interpretation) of their cancer risks and heredity likelihood (P→O), or this perception mediated the outcome (I→P→O). However, this perception was significantly different from the actually communicated cancer risks (I→P). Unclassified variants were inaccurately perceived (mostly overestimated); this misperception predicted both psychological outcomes and radical medical decisions.
Genetic counselors need to explicitly address the counselee's interpretations and intended medical decisions. In case of misinterpretations, additional counseling might be offered. Communication of unclassified variants needs special attention given the pitfall of overestimation of risk.
[Show abstract][Hide abstract] ABSTRACT: Genetic counseling may help counselees understand their genetic risk of developing breast/ovarian cancer. However, many studies have shown that their perception of their risks is inaccurate. Information-oriented variables often predicted the level of accuracy, focusing on specific processes of receiving and processing risks. We examined counselee-oriented predictors about how counselees embed cancer risks in their lives. These predictors reflect the personal meaning of genetic risks and are expected to explain/mediate the impact of genetic counseling on risk-perception-accuracy.
We analyzed 248 questionnaires of a prospective study, filled in by probands with breast/ovarian cancer and pathogenic mutations, unclassified variants, or uninformative results (n = 30, 16, and 202, respectively). Mediation regression analyses were performed to examine whether counselee predictors mediated/explained the influence of information predictors on the accuracy. Information-oriented predictors regarded presentation format, communicated information, question format, education, pedigree information, cancer experience, and cognitive processes/heuristics. Counselee-oriented predictors regarded their self/personality, life/existence, and need for certainty about DNA test result, heredity, and cancer.
Both information-oriented and counselee-oriented variables significantly predicted the accuracy of the counselees' risk perception, with moderate to large effect sizes. Counselee-oriented variables completely mediated/explained the effects of information-oriented variables on the accuracy.
Counselees seemed to transform objective cancer risks into personally relevant information. Only through this personal meaning of genetic information, information-oriented processes seemed to cause inaccurate perceptions. Genetic counselors are suggested to focus communication on these personal processes.
Full-text · Article · Sep 2011 · Genetics in medicine: official journal of the American College of Medical Genetics
[Show abstract][Hide abstract] ABSTRACT: Previous studies suggest that learning a DNA-test-result has no direct impact on the medical-decisions and psychological well-being of counselees. Their perception, especially their recollections and interpretations of their cancer-risks and heredity, predict and/or mediate this impact. These studies were criticized for their small range of predictors, mediators, outcomes and contextual factors. We studied the short-term impact of DNA-testing with an extended model.
Three months after disclosure of BRCA1/2-test-results, we sent counselees a questionnaire about their perception, medical and psychological outcomes, and medical, familial and psychological contexts. 248 affected women participated; 30 had received pathogenic-mutations, 16 unclassified-variants and 202 uninformative-results.
The actually communicated genetic-information and the contextual variables predicted the counselees' perception, but did not directly predict any outcomes. The counselees' perception predicted and/or completely mediated the counselees' medical intentions and behavior, physical and psychological life-changes, stigma, mastery, negativity and cancer-worries. Short-term distress was related to the perception not only of their own risks, but also of their relatives' risks and heredity-likelihood. Effect sizes were medium to large.
The outcomes of DNA-testing were better predicted by the counselees' perception than by the actually given genetic-information. We recommend genetic-counselors to have tailored, interactive dialogues about the counselees' perception.
No preview · Article · Jun 2011 · Patient Education and Counseling
[Show abstract][Hide abstract] ABSTRACT: Li Fraumeni syndrome (LFS) and Von Hippel-Lindau disease (VHL) are two rare hereditary tumor syndromes, characterized by a high risk of developing multiple tumors at various sites and ages for which preventive and treatment options are limited. For partners, it may be difficult to deal with the on-going threat of tumors in both their spouse and children. Therefore, this study aims to evaluate the prevalence of and factors associated with psychological distress among partners of individuals with or at high risk of LFS or VHL.
As part of a nationwide, cross-sectional study, partners of individuals diagnosed with or at high risk of LFS or VHL were invited to complete a self-report questionnaire assessing distress, worries, and health-related quality of life.
Fifty-five (58%) of those high-risk individuals with a partner consented to having their partner approached for the study. In total, 50 partners (91%) completed the questionnaire, of whom 28% reported clinically relevant levels of syndrome-related distress. Levels of distress and worries of the partners and their high-risk spouse were significantly correlated. Younger age and a lack of social support were also associated significantly with heightened levels of distress and worries. The majority of partners (76%) believed that professional psychosocial support should be routinely offered to them.
Approximately one-quarter of the partners exhibit clinically relevant levels of distress that warrant psychological support. The distress levels of the 'patient' could potentially be used to identify partners at risk of developing clinically relevant levels of distress.