Differential role of gene hypermethylation in adenocarcinomas, squamous cell carcinomas and cervical intraepithelial lesions of the uterine cervix.

Cervical cancer is the third most common cancer in women worldwide. The hypermethylation of P16, TSLC-1 and TSP-1 genes was analyzed in squamous cell carcinomas (SCC), cervical intraepithelial lesions (CIN) and adenocarcinomas (ADC) of the uterine cervix (total 181 lesions). Additionally human papillomavirus (HPV) type, EPB41L3, RASSF1 and RASSF2 hypermethylation were tested in ADC and the results were compared with those obtained previously by our group in SCC. P16, TSLC-1 and TSP-1 hypermethylation was more frequent in SCCs than in CINs. These percentages and the corresponding ones for EPB41L3, RASSF1 and RASSF2 genes were also higher in SCCs than in ADCs, except for P16. The presence of HPV in ADCs was lower than reported previously in SCC and CIN. Patients with RASSF1A hypermethylation showed significantly longer disease-free survival (P = 0.015) and overall survival periods (P = 0.009) in ADC patients. To our knowledge, this is the first description of the EPB41L3 and RASSF2 hypermethylation in ADCs. These results suggest that the involvement of DNA hypermethylation in cervical cancer varies depending on the histological type, which might contribute to explaining the different prognosis of patients with these types of tumors.

Differential gene hypermethylation in genital lichen sclerosus and cancer: a comparative study.

AIMS: Lichen sclerosus (LS) is a chronic inflammatory disease of the genital skin of unknown aetiology. The role of LS in penile squamous cell carcinogenesis is not well characterized. HPV has been implicated in both, as have epigenetic changes. The presence of HPV and hypermethylation of the MGMT, p16, RASSF1, RASSF2, TSLC1 and TSP1 genes were studied in penile LS; MGMT, RASSF2 and TSLC1 hypermethylation in penile cancer and TSLC1 hypermethylation in vulvar LS and cancer extends previous results reported by our group. METHODS AND RESULTS: Thirty-seven HPV genotypes and hypermethylation were evaluated by PCR/reverse-line-blot and methylation-specific PCR respectively, in 27 preputial LS, 24 penile SCC, 30 vulvar SCC, 21 vulvar LS and 22 normal skin cases. HPV66 was present in 3.7% of penile LS cases, and p16 and RASSF2 hypermethylation were more frequent in penile cancer than in penile LS. p16, RASSF1, RASSF2 and TSP1 hypermethylation were similar in penile and vulvar LS. CONCLUSIONS: Gene hypermethylation is a common event in penile LS, and occurs approximately as frequently as in vulvar LS. Certain genes can be hypermethylated as an early or late event in LS or cancer, respectively. This suggests a possible sequential role for these alterations in the transition from benign to malignant lesions.

RASSF2 hypermethylation is present and related to shorter survival in squamous cervical cancer.

Ras association (RalGDS/AF-6) domain family member 2 (RASSF2) is a gene involved in the progression of several human cancers, including breast, colorectal and lung cancer. The aims of this study were to determine the hypermethylation of the gene in squamous cervical cancer and precursor lesions, along with that of RASSF1 and the recently described EPB41L3, and to analyze the potential prognostic role of these genes. Methylation-specific PCR and bisulfite sequencing were used to analyze the methylation status of RASSF2 and EPB41L3 gene in 60 squamous cervical cancer, 76 cervical intraepithelial neoplasias grade III, 16 grade II, 14 grade I and 13 cases of normal tissue adjacent to cervical intraepithelial neoplasia. RASSF2 expression was evaluated by immunohistochemistry and the re-expression of RASSF2 and EPB41L3 was analyzed by quantitative reverse-transcription PCR in HeLa, SiHa, C33A and A431 cell lines treated with 5-aza-2'-deoxycytidine and/or trichostatin. RASSF1 hypermethylation and human papillomavirus type were also analyzed in all the cases by methylation-specific PCR and reverse line blot, respectively. RASSF2 hypermethylation was predominant in squamous cervical cancer (60.9%) compared with cervical intraepithelial neoplasias (4.2%) and was associated with a lower level of RASSF2 expression and vascular invasion in squamous cervical cancer. EPB41L3 and RASSF1 hypermethylations were also more frequent in cancer than in precursor lesions. Patients with RASSF2 hypermethylation had shorter survival time, independent of tumor stage (hazard ratio: 6.0; 95% confidence interval: 1.5-24.5). Finally, the expressions of RASSF2 and EPB41L3 were restored in several cell lines treated with 5-aza-2'-deoxycytidine. Taken together, our results suggest that RASSF2 potentially functions as a new tumor-suppressor gene that is inactivated through hypermethylation in cervical cancer and is related to the bad prognosis of these patients.

Differential hypermethylation of genes in vulvar cancer and lichen sclerosus coexisting or not with vulvar cancer.

Squamous cell carcinoma (SCC) of the vulva is a heterogeneous disease, associated or not with vulvar lichen sclerosus (LS). The precursor role of LS in vulvar cancer is unclear. We studied the epigenetic alterations of RASSF1A, RASSF2A, p16, TSP-1 and MGMT genes in vulvar SCCs, LS associated with SCC, isolated LS and normal vulvar skin. Gene hypermethylation and human papillomavirus presence were evaluated by methylation-specific PCR and PCR/reverse line blot, respectively. High-risk human papillomavirus types were present in 16.7% of the patients with vulvar SCC. There were increasing percentages of hypermethylation of genes from isolated LS to LS associated with vulvar SCC and vulvar SCC. The genes were hypermethylated more frequently in vulvar SCC associated with LS than in those not associated with LS, MGMT and RASSF2A being unmethylated in LS not associated with vulvar SCC. TSP-1 hypermethylation was related to recurrence in patients with vulvar cancer. Conclusions are as follows: (i) the epigenetic inactivation of genes is a common event in vulvar SCC and is also present in adjacent lesions, implying a possible precursor role for these alterations; (ii) MGMT and RASSF2A hypermethylation are present exclusively in vulvar SCC and LS associated with SCC, and absent from isolated LS; and (iii) TSP-1 hypermethylation is a bad prognosis factor in vulvar SCC.

Hypermethylation of the thrombospondin-1 gene is associated with poor prognosis in penile squamous cell carcinoma.

OBJECTIVE: To evaluate the presence of human papillomavirus (HPV) infection, the methylation status in the promoter region of thrombospondin-1 (TSP-1), RAS association domain family 1A (RASSF1-A) and p16 genes, and the expression of TSP-1, CD31, p16 and p53 proteins in patients diagnosed with penile cancer, and the possible associations between these variables and clinical and pathological features. PATIENTS AND METHODS: HPV types, gene promoter hypermethylation and protein expression were analysed by reverse line blot, methylation-specific polymerase chain reaction, and immunohistochemistry, respectively, in 24 penile squamous cell carcinomas. RESULTS: HPV infection was detected in 11 of 24 cases (46%), and TSP-1, RASSF1-A and p16 genes were hypermethylated in 46%, 42% and 38% of the tumours, respectively. TSP-1 hypermethylation was associated with unfavourable histological grade (grade 3; P = 0.033), vascular invasion (P = 0.023), weak expression of TSP-1 protein (P = 0.041), and shorter overall survival (P = 0.04). TSP-1 expression was not associated with microvessel density. However, RASSF1-A hypermethylation was more frequent in T1 tumours (P = 0.01), and p16 hypermethylation was not associated with any of the tested variables except for absence of p16 expression (P = 0.022). CONCLUSION: In summary, the epigenetic inactivation of TSP-1 and RASSF1-A genes is associated with pathological variables and seems to be of prognostic significance in penile cancer.