[show abstract][hide abstract] ABSTRACT: The incidence of oral cancer remains high and is associated with many deaths in both Western and Asian countries. Several risk factors for the development of oral cancer are now well known, including smoking, drinking and consumption of smokeless tobacco products. Genetic predisposition to oral cancer has been found in certain cases but its components are not yet entirely clear. In accordance with the multi-step theory of carcinogenesis, the natural history of oral cancer seems to gradually evolve through transitional precursor lesions from normal epithelium to a full-blown metastatic phenotype. A number of genomic lesions accompany this transformation and a wealth of related results has appeared in recent literature and is being summarized here. Furthermore, several key genes have been implicated, especially well-known tumor suppressors like the cyclin-dependent kinase inhibitors, TP53 and RB1 and oncogenes like the cyclin family, EGFR and ras. Viral infections, particularly with oncogenic HPV subtypes and EBV, can have a tumorigenic effect on oral epithelia and their role is discussed, along with potential therapeutic interventions. A brief explanatory theoretical model of oral carcinogenesis is provided and potential avenues for further research are highlighted.
[show abstract][hide abstract] ABSTRACT: Claspin is a nuclear protein involved in DNA replication and the DNA damage response. Its structural and functional properties suggest that it may represent a potentially useful proliferation marker. To this end, a monoclonal antibody was generated and the expression of claspin was investigated in normal fibroblasts and various cancer cell lines, as well as in tumour and normal tissues from patients with primary epithelial carcinomas. Immunoblotting analysis confirmed the specificity of the antibody, while immunohistochemistry demonstrated its applicability in archival material. In normal cells and tissues, claspin expression was weak, whereas increased levels were observed in cancer cell lines and tumour specimens. Claspin staining correlated strongly with Ki67 staining in both normal (p < 0.001) and tumour tissues (p < 0.001). However, the labelling index (LI) of claspin was consistently lower than that of Ki67, suggesting that claspin expression may be limited to a narrower part of the cell cycle. Co-localization assays with cyclin A and cell synchronization experiments indicated that claspin expression coincides with the S phase. Interestingly, the relative increase of the claspin LI in tumour samples compared with normal tissues was significantly higher (14-fold) than that of the Ki67 LI (five-fold), suggesting that claspin may be a more sensitive marker of aberrant proliferation.
The Journal of Pathology 02/2007; 211(3):331-9. · 7.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: To investigate whether immunocytochemical detection of cytokeratin (CK)-20 could serve as a reliable diagnostic marker for transitional cell carcinoma (TCC) of the bladder.
A total of 232 patients were enrolled in the study. Group 1 consisted of 144 patients with histologically confirmed TCC (62 at diagnosis and 82 in follow-up), and group 2 consisted of 88 subjects, including healthy volunteers and individuals with "non-TCC" conditions. Spontaneously voided urine specimens were obtained from each patient and submitted to immunocytologic and standard cytologic examination.
CK-20 immunocytology yielded an overall sensitivity of 65.3%, significantly greater than the sensitivity of urine cytology (54.2%, P = 0.013). A more detailed analysis revealed a sensitivity advantage for the former technique in the detection of primary (61.3% versus 51.6%, P = 0.046), recurrent (68.3% versus 56.1%, P = 0.027), Stage pT1 (81.8% versus 59.1%, P = 0.006), grade 2 (76.2% versus 61.9%, P = 0.031), and grade 3 (82.1% versus 67.9%, P = 0.039) tumors. Moreover, CK-20 immunocytochemistry demonstrated greater overall specificity than cytology (90.9% versus 86.4%, respectively), a difference stemming from the subgroup of lithiasis patients (100% versus 66.7%, P = 0.024). In terms of reliability, the positive and negative predictive values of the immunoassay were greater than those calculated for cytology (92.2% versus 86.7% and 61.5% versus 53.5%, respectively).
CK-20 immunocytology is more sensitive than standard cytology in the detection of TCC, particularly of Stage pT1, grade 2, and grade 3 tumors. In view of its high overall specificity and predictive accuracy, it is conceivable that the proposed immunoassay may progressively replace conventional cytologic screening in the diagnosis of bladder cancer.
[show abstract][hide abstract] ABSTRACT: DNA damage checkpoint genes, such as p53, are frequently mutated in human cancer, but the selective pressure for their inactivation remains elusive. We analysed a panel of human lung hyperplasias, all of which retained wild-type p53 genes and had no signs of gross chromosomal instability, and found signs of a DNA damage response, including histone H2AX and Chk2 phosphorylation, p53 accumulation, focal staining of p53 binding protein 1 (53BP1) and apoptosis. Progression to carcinoma was associated with p53 or 53BP1 inactivation and decreased apoptosis. A DNA damage response was also observed in dysplastic nevi and in human skin xenografts, in which hyperplasia was induced by overexpression of growth factors. Both lung and experimentally-induced skin hyperplasias showed allelic imbalance at loci that are prone to DNA double-strand break formation when DNA replication is compromised (common fragile sites). We propose that, from its earliest stages, cancer development is associated with DNA replication stress, which leads to DNA double-strand breaks, genomic instability and selective pressure for p53 mutations.
[show abstract][hide abstract] ABSTRACT: Replication licensing ensures once per cell cycle replication and is essential for genome stability. Overexpression of two key licensing factors, Cdc6 and Cdt1, leads to overreplication and chromosomal instability (CIN) in lower eukaryotes and recently in human cell lines. In this report, we analyzed hCdt1, hCdc6, and hGeminin, the hCdt1 inhibitor expression, in a series of non-small-cell lung carcinomas, and investigated for putative relations with G(1)/S phase regulators, tumor kinetics, and ploidy. This is the first study of these fundamental licensing elements in primary human lung carcinomas. We herein demonstrate elevated levels (more than fourfold) of hCdt1 and hCdc6 in 43% and 50% of neoplasms, respectively, whereas aberrant expression of hGeminin was observed in 49% of cases (underexpression, 12%; overexpression, 37%). hCdt1 expression positively correlated with hCdc6 and E2F-1 levels (P = 0.001 and P = 0.048, respectively). Supportive of the observed link between E2F-1 and hCdt1, we provide evidence that E2F-1 up-regulates the hCdt1 promoter in cultured mammalian cells. Interestingly, hGeminin overexpression was statistically related to increased hCdt1 levels (P = 0.025). Regarding the kinetic and ploidy status of hCdt1- and/or hCdc6-overexpressing tumors, p53-mutant cases exhibited significantly increased tumor growth values (Growth Index; GI) and aneuploidy/CIN compared to those bearing intact p53 (P = 0.008 for GI, P = 0.001 for CIN). The significance of these results was underscored by the fact that the latter parameters were independent of p53 within the hCdt1-hCdc6 normally expressing cases. Cumulatively, the above suggest a synergistic effect between hCdt1-hCdc6 overexpression and mutant-p53 over tumor growth and CIN in non-small-cell lung carcinomas.
American Journal Of Pathology 11/2004; 165(4):1351-65. · 4.52 Impact Factor
[show abstract][hide abstract] ABSTRACT: To assess the value of the telomerase enzyme as a bladder cancer detection marker, we investigated the expression of the catalytic subunit of the complex (human telomerase reverse transcriptase [hTERT]) in the urine of patients with malignant or benign urinary lesions, as well as of healthy individuals, and compared the results with urine cytology.
Spontaneously voided samples were obtained from two groups of subjects: group 1, 146 previously untreated patients with a histologic diagnosis of transitional cell carcinoma or other urothelial neoplasm; and group 2, 128 control individuals, either healthy or with a nonmalignant bladder disease. Total RNA extracts from sedimented urothelial cells were analyzed by a reverse transcriptase-polymerase chain reaction assay for the presence of a 146-bp hTERT transcript. Urine samples were also examined by standard cytology.
Expression of hTERT was detected in 134 (92%) of 146 patients with bladder cancer, and only 64 (44%) yielded a positive result by cytology (P <0.001). The sensitivity advantage of the former technique became particularly evident in the detection of low-grade transitional cell carcinoma (93% versus 28%, P <0.001). Accordingly, the negative predictive value of the molecular assay was markedly greater than the one calculated for cytologic screening (91% versus 60%). On the other hand, both methods were at least 96% specific, with their positive predictive indexes exceeding 94%.
Our findings suggest that the assessment of hTERT expression in urine sediments represents a reliable tool for the detection of primary urothelial neoplasms, equally specific, yet far more sensitive, than conventional cytology.
[show abstract][hide abstract] ABSTRACT: To assess the incidence of multicentricity in our series of renal cell carcinoma (RCC) patients and to investigate whether certain clinicopathological parameters could assist the selection of the appropriate surgical modality.
We performed a retrospective analysis of 235 RCC specimens that had been resected by radical nephrectomy at our institution from June 1995 to 2001.
Twenty-six (11%) kidneys contained at least one small accompanying nodule. Fourteen (6%) kidneys exhibited satellite tumors that were histologically consistent with the adenomas, while "true" multicentricity was detected in 12 (5%) specimens. In the latter, the number of concomitant foci was independent of the size of the primary tumor. No correlation was observed between histological pattern and multifocality. In five out of seven (71%) specimens that contained the main tumor mass within the upper or middle portion of the kidney, satellite lesions were found to be located at the mid-kidney, whereas specimens with lower-pole RCC demonstrated no restriction in the distribution of accompanying nodules. All patients had been screened pre-operatively by ultrasonography and CT scanning.
Our findings may be suggestive of a putative link between primary tumor location and multicentricity, although this relation could not be statistically confirmed. The 5% incidence of multicentricity renders the biological significance of satellite adenomas and/or adenocarcinomas unclear.
European Urology 04/2002; 41(3):262-6. · 10.48 Impact Factor
[show abstract][hide abstract] ABSTRACT: This review aims in presenting the established and putative prognostic markers in non-small cell lung carcinoma (NSCLC). We have focused on the molecular/genetic alterations accompanying the pathogenesis of this malignancy, which may derange the cellular response to external and internal stimuli. A variety of factors influencing cell cycle progression, programmed cell death, drug resistance and immune evasion seem to obtain a predictive--though sometimes argued--role. Taking into account that a great number of these factors develope "cross-talking" protein-complex networks, their combined evaluation is likely to contribute towards a more accurate prediction of the clinical outcome in NSCLC patients.
Anticancer research 01/2002; 22(1A):347-74. · 1.71 Impact Factor
[show abstract][hide abstract] ABSTRACT: Down-regulation or overexpression of the cyclin-dependent kinase inhibitor p27 have been observed in a range of malignancies, including lung cancer. To further elucidate the role of the molecule in tumor growth regulation, we evaluated p27 expression in a series of non-small cell lung carcinomas (NSCLCs), and examined its relation with histology, kinetic parameters, ploidy, and overall survival. We extended our investigation into the association of p27 levels with the presence of Ki-ras mutations, as well as with the expression status of p53 and pRb in tumor cells.
p27, p53, and pRb status were immunohistochemically evaluated in a total of 69 NSCLCs. In situ assays were employed to assess the kinetic parameters (Ki-67 immunohistochemistry for proliferation index, Tdt-mediated dUTP nick end labeling assay for apoptotic index). The ploidy status of the tumors was assessed after staining nuclei with the Feulgen procedure, and the presence of Ki-ras mutations was examined by restriction fragment length polymorphisms. All possible associations were assessed with a series of statistical methods.
Immunoreactivity for p27 was observed in the entire series of specimens, with the mean percentage of positive cells being 33%. Adenocarcinomas (AdCs) exhibited higher p27 levels compared to squamous cell carcinomas (SqCCs) (p < 0.01). An inverse correlation was established between p27 expression and proliferation index (PI) (r = -0.834, p < 0.01) but not with apoptotic index (AI), whereas aneuploid tumors were characterized by lower p27 levels than diploid ones (p < 0.01). No difference in p27 immunostaining was observed with regard to the presence of Ki-ras mutations, whereas aberrant p53 and/or pRb expression patterns were associated with p27 underexpression (p < 0.01 for p53 status, p < 0.05 regarding pRb levels, and p < 0.01 for a combined deregulation of both proteins). Two or more alterations in the p27/p53/pRb protein network (i.e., p27 levels lower than the estimated mean value, overexpressed p53, and/or aberrant pRb) were associated with increased PI and aneuploidy (p < 0.001 and p < 0.01, respectively). A powerful trend was found between p27 expression and overall survival (p = 0.066).
Our findings confirm the heterogeneity between AdCs and SqCCs, and are suggestive of an increased proliferative activity in NSCLCs underexpressing p27. Furthermore, our analysis supports the concept of p27 forming a functionally compact network with p53 and pRb, which is actively involved in the regulation of cellular proliferation and chromosomal stability.
Molecular Medicine 07/2001; 7(6):418-29. · 4.47 Impact Factor
[show abstract][hide abstract] ABSTRACT: The FHIT gene, located at the FRA3B fragile site of chromosome 3p14.2, encodes a 16.8 kD homologue of the yeast enzyme diadenosine tetraphosphate (Ap(4)A) hydrolase. Frequent allelic losses at this region in various malignancies, including non-small cell lung carcinomas (NSCLCs), imply that FHIT may represent a tumour suppressor gene (TSG). Increasing evidence suggests that multiple TSG impairment has a synergistic effect on tumour growth. The present study of 67 NSCLCs investigated the allelic imbalance (AIm) within the FHIT locus and its relationship with p53 abnormalities, kinetic parameters [proliferative activity or proliferation index (PI) and apoptotic index (AI)], and ploidy status of the carcinomas. Allelic imbalance at FHIT was observed in 35 out of 55 informative (heterozygous: H) cases (64%). Similar frequencies of loss of heterozygosity (LOH) were noticed among squamous cell lung carcinomas and adenocarcinomas. The high percentage of AIm in stage I tumours (71%) is indicative of its relatively early involvement in NSCL carcinogenesis. No association was found between LOH at FHIT, kinetic parameters, and ploidy status of the tumours. Concurrent loss at FHIT and p53 overexpression [FHIT(LOH)/p53(P)] was the most frequent pattern and was observed in 39% of the informative cases. The latter pattern was not associated with smoking, supporting the hypothesis that in patients with a history of tobacco exposure, FHIT allelic loss may not be a consequence of p53 checkpoint defects, but the outcome of tobacco-induced mutagenesis. Statistically significant differences in the presence of FHIT(LOH)/p53(P) and FHIT(LOH)/p53(N) patterns were noted at the proliferative and apoptotic level, whereas ploidy was similar amongst all groups, implying that wild-type (wt) p53 may play a safeguard role against altered FHIT function. However, the possibility of a masking effect from wt p53 cannot be excluded, since the FHIT(LOH)/p53(P) profile demonstrated a higher growth index (GI=PI/AI mean value ratio) than FHIT(H)/p53(P) (32 vs. 8), although this was not significant. Further studies are needed in order to elucidate the role of FHIT and its relationships with other cell-cycle regulatory molecules involved in NSCL carcinogenesis.
The Journal of Pathology 02/2001; 193(1):55-65. · 7.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: A polymerase chain reaction (PCR) assay targeted to the immunogenic protein MPB64 gene was used to detect members of the Mycobacterium tuberculosis complex, and an outward-primed PCR (OPPCR) designed on the IS6110 element allowed differentiation between Mycobacterium bovis and Mycobacterium tuberculosis. Additionally, the amplification of IS1110 and 16S ribosomal RNA sequences combined with a dot blotting assay were able to differentially detect Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium paratuberculosis. The validity of the experimental procedure was tested on reference material and formalin-fixed paraffin-embedded samples from patients with tuberculosis, sarcoidosis, or Crohn disease. We demonstrated mycobacterial DNA in 59 of 75 cases with histologic lesions typical of tuberculosis; we detected M tuberculosis and M paratuberculosis in 6 of 25 sarcoidosis cases and in 7 of 20 Crohn disease specimens, respectively. The proposed diagnostic procedure is directly applicable to archival material and allows differentiation of genetically related mycobacterial pathogens in more detail than other molecular methods. It provides a tool for the diagnostic study of tuberculosis, sarcoidosis, and Crohn disease.
American Journal of Clinical Pathology 01/2001; 114(6):940-50. · 2.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: Little is known about the status of the mitogen-activating protein kinase pathways in lung cancer. One of the key molecules taking part in these pathways is the product of the c-mos proto-oncogene, which plays an important role in oocyte maturation. In vitro investigations in somatic cells have shown that c-mos expression has opposing effects on the cell cycle, which suggests that this proto-oncogene may represent an important determinant of aberrant cell function (genomic instability and altered kinetics). A recent study suggests that these effects may be p53 dependent. In view of the apparent link between c-mos and p53, we investigated in a series of 56 non-small cell lung carcinomas: a) the status of c-mos; b) its relationship to genomic instability (aneuploidy) and two kinetic parameters of the tumors, proliferation and apoptotic indexes (AI); and c) its association with p53 alterations and their concomitant relationship with the above parameters. We found c-mos overexpression in 27% of the tumors. Expression was higher in stages II/III (34%) than in stage I (17%; P = 0.018). Complete concordance was observed between c-mos overexpression and elevated c-mos mRNA levels. Because c-mos gene amplification was not detected, its deregulated expression may be attributable to increased transcription. Of the c-mos positive [c-mos(P)] cases, 77% were associated with aneuploidy. Sequencing showed two silent mutations and one missense (R-->L) at codon 22, located in a region critical for c-mos stability. In contrast to the findings of some in vitro studies, c-mos(P) tumors had a lower mean AI score than the c-mos negative [c-mos(N)] tumors had, implying that induction of apoptosis may have been defective. Indeed, 86% of the tumors overexpressing c-mos showed p53 alterations. The carcinomas with concomitant alterations of c-mos and p53 [c-mos(P)/p53 positive] had significantly lower AI values (P < 0.001) and were more frequently associated with aneuploidy (P = 0.015) than the c-mos(N)/p53 negative tumors but not the c-mos(N)/p53 positive tumors, which suggests that p53 status is the main determinant of ploidy status and apoptosis in our series. This finding also strengthens the concept that wild-type p53 plays a "safeguard" role in preventing oncogene-mediated activation.
Cancer Research 01/2001; 61(2):538-49. · 8.65 Impact Factor
[show abstract][hide abstract] ABSTRACT: Multiple myeloma (MM) is a B-cell neoplasm characterized by bone marrow infiltration with malignant plasma cells, which synthesize and secrete monoclonal immunoglobulin (Ig) fragments. Despite the considerable progress in the understanding of MM biology, the molecular basis of the disease remains elusive. The initial transformation is thought to occur in a postgerminal center B-lineage cell, carrying a somatically hypermutated Ig heavy chain (IGH) gene. This plasmablastic precursor cell colonizes the bone marrow, propagates clonally and differentiates into a slowly proliferating myeloma cell population, all under the influence of specific cell adhesion molecules and cytokines. Production of interleukin-6 by stromal cells, osteoblasts and, in some cases, neoplastic cells is an essential element of myeloma cell growth, with the cytokine stimulus being delivered intracellularly via the Jack-STAT and ras signaling pathways. While karyotypic changes have been identified in up to 50% of MM patients, recent molecular cytogenetic techniques have revealed chromosomal abnormalities in the vast majority of examined cases. Translocations mostly involve illegal switch rearrangements of the IGH locus with various partner genes (CCND1, FGFR3, c-maf). Such events have been assigned a critical role in MM development. Mutations in coding and regulatory regions, as well as aberrant expression patterns of several oncogenes (c-myc, ras) and tumor suppressor genes (p16, p15) have been reported. Key regulators of programmed cell death (BCL-2, Fas), tumor expansion (metalloproteinases) and drug responsiveness (topoisomerase II alpha) have also been implicated in the pathogenesis of this hematologic malignancy. A tumorigenic role for human herpesvirus 8 (HHV8) was postulated recently, following the detection of viral sequences in bone marrow dendritic cells of MM patients. However, since several research groups were unable to confirm this observation, the role of HHV8 remains unclear. Translation of the advances in MM molecular biology into novel therapeutic strategies is essential in order to improve disease prognosis.
Annals of Oncology 11/2000; 11(10):1217-28. · 7.38 Impact Factor
[show abstract][hide abstract] ABSTRACT: Studies on the implication of mycobacteria in the pathogenesis of sarcoidosis have generated conflicting results. In an attempt to further elucidate the etiology of the disease, we obtained broncho-alveolar lavage (BAL) samples from sarcoidal patients, which were subsequently used for intra-tracheal inoculation of a group of rabbits. Patients were characterized as sarcoidal on the grounds of clinical, radiographic, histological and microbiological testing. Four months following inoculation, lung and alveolar lymph node specimens were collected from the animals and were examined by means of histology and microbiology, as well as by a polymerase chain reaction (PCR) assay, targeted to DNA sequences of the Mycobacterium tuberculosis and Mycobacterium avium complexes. All of the twenty five BAL-inoculated rabbits revealed evidence of lobar pneumonia, with thirteen developing lesions of non-caseous granulomatous inflammation, similar to those observed in sarcoidal patients. Microbiological cultivation of lung and alveolar lymph node material, Zihl-Neelsen staining of corresponding tissue sections and PCR analysis of extracted DNA yielded no evidence of mycobacterial infection. Identical processing of biopsies originating from the martyrs, formerly inoculated with drinking water or disinfected BAL, revealed no pathological signs. Our findings suggest that BAL samples from patients with sarcoidosis may carry an agent that produces a disease characterized by similar histological lesions in rabbits. However, culture, and PCR, could not identify this agent as a member of Mycobacterium tuberculosis, or Mycobacterium avium complexes.
In vivo (Athens, Greece) 01/2000; 14(6):761-5. · 1.22 Impact Factor