ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the status of promoter hypermethylation of Ras association domain family protein 1A (RASSF1A), hypermethylated in cancer 1 (HIC1) and p73 genes in hepatocellular carcinoma (HCC) and to explore the correlation with clinicopathological features.</p><p><b>METHODS</b>Forty cases of HCC and their corresponding non-tumor liver tissues, other 2 cases of healthy donor livers were detected using methylation specific polymorphism chain reaction (MSP) method.</p><p><b>RESULTS</b>The frequency of promoter hypermethylation of RASSF1A showed 90.0% and 72.5% in tumor and corresponding non-tumor tissues respectively, and there was significant difference between them (P < 0.05). The frequency of promoter hypermethylation of HIC1 showed 77.5% and 70.0% in tumor and corresponding non-tumor tissues respectively. The frequency of hypermethylation of HIC1 in non-tumor liver tissues showed significant correlation between younger and older patients. The frequency of promoter hypermethylation of p73 showed 5.0% in tumor tissues. However, none of hypermethylation of the gene was detected in corresponding non-tumor liver tissues. There was none of hypermethylation of the three genes showed in two cases of healthy donor livers.</p><p><b>CONCLUSION</b>Promoter hypermethylation of RASSF1A and HIC1 genes are common event in HCC and play an important role in the pathogenesis and may be used to develop novel diagnostic and therapeutic approaches for HCC in the future.</p>
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Carcinoma, Hepatocellular , Genetics , Pathology , Cell Line, Tumor , DNA Methylation , DNA-Binding Proteins , Genetics , Gene Expression Regulation, Neoplastic , Kruppel-Like Transcription Factors , Genetics , Liver Neoplasms , Genetics , Pathology , Nuclear Proteins , Genetics , Promoter Regions, Genetic , Genetics , Reverse Transcriptase Polymerase Chain Reaction , Tumor Protein p73 , Tumor Suppressor Proteins , GeneticsABSTRACT
<p><b>OBJECTIVE</b>The FHIT (fragile histidine triad) is a candidate tumor suppressor gene (TSG) located on chromosome 3p14.2. Hypermethylation and loss of heterozygosity (LOH) are major mechanisms in the inactivation of tumor suppressor genes. In this study, the methylation status of FHIT and LOH of 3p14 in 61 cases of human sporadic ovary carcinomas were investigated.</p><p><b>METHODS</b>Sixty-one primary ovary carcinomas and 10 borderline ovarian tumors were analyzed with methylation specific PCR (MSP) to detect the CpG island methylation status in the FHIT promoter region. In addition, 45 cases of ovary carcinomas and their corresponding non-tumor ovary tissues were investigated with D3S1287 microsatellite polymorphic marker for LOH.</p><p><b>RESULTS</b>Hypermethylation of FHIT gene was observed in 39.3% (24/61) of ovarian carcinomas. The frequencies of hypermethylation in serous ovarian carcinoma, mucinous ovarian carcinoma, endometrioid ovarian carcinoma and ovary borderline tumor were 45.2% (19/42), 14.3% (1/7), 33.3% (4/12) and 60.0% (6/10), respectively. Ten of twenty-three (43.5%) informative tumors showed LOH and 6 of 18 (33.3%) informative cases showed homozygous deletions. The status of FHIT methylation was not associated with clinical stage and differentiation grade, there was no significant difference between the malignant and borderline tumors.</p><p><b>CONCLUSION</b>Hypermethylation and allelic deletion of FHIT are frequent events in ovarian carcinomas and are important mechanisms for the loss of expression of this gene.</p>
Subject(s)
Adult , Aged , Aged, 80 and over , Female , Humans , Middle Aged , Acid Anhydride Hydrolases , Genetics , Metabolism , Chromosomes, Human, Pair 3 , CpG Islands , Cystadenocarcinoma, Serous , Genetics , Metabolism , DNA Methylation , DNA, Neoplasm , Genetics , Genes, Tumor Suppressor , Loss of Heterozygosity , Neoplasm Proteins , Genetics , Metabolism , Ovarian Neoplasms , Genetics , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To assess the role of methylated mismatch repair (MMR) genes (hMLH1, hMSH2 and hMSH3) in the carcinogenesis and progression of hepatocellular carcinoma (HCC).</p><p><b>METHODS</b>Samples of 38 cases of HCC along with their corresponding noncancerous tissues, 2 samples of donated normal tissue and 6 cell lines were collected and subject to the methylation-specific PCR (MSP) to examine promoter methylation status of MLH1, MSH2 and MSH3. Six tumor cell lines were analyzed before and after 5-aza-2'-deoxycytidine treatment. In addition, alterations of mRNA expression of MMRs were investigated by quantitative reverse transcription-PCR.</p><p><b>RESULTS</b>CpG island methylation of hMLH1 and hMSH2 was observed in 13.2% (5 of 38 samples) and 68.4% (26 of 38 samples) respectively in HCC, 2.6% (1 of 38 samples) and 55.3% (21 of 38) respectively in corresponding noncancerous tissues, but not in normal control tissues. Promoter methylation of the hMSH2 gene was present in 83.3% of cell lines tested (5/6), but none were observed for the hMLH1 gene. Promoter methylation of the hMSH3 gene was not identified in any tissue samples or cell lines. After 5-aza-2'-deoxycytidine treatment, hMSH2 methylation was induced or completely reversed, and its mRNA expression was increased in most cell lines.</p><p><b>CONCLUSIONS</b>Our results suggest that promoter hypermethylation of hMLH1 and hMSH2 genes is common in HCC. Particularly, there is a high frequency of methylation of hMSH2 in both cancer and noncancerous tissues, but not in normal control tissue. Therefore, hypermethylation of MMR genes, especially hMSH2, may be involved in the carcinogenesis of HCC and may serve as an early diagnostic marker for HCC. The close correlation between hMSH2 methylation and low expression of its mRNA suggests that hMSH2 methylation is an important pathway in the regulation of gene expression.</p>