| Objective (1)To determine the relationship between mRNA expression andpromoter methylation of RASSF1A gene in hepatocellular carcinoma (2)Toinvestigate the lever of promoter methylation of RASSF1A gene in hepatocellularcarcinoma and its clinic pathological significance.Methods (1) MS-PCR was used for analyzing the status of aberrant promotermethylation of RASSF1A in65primary HCC samples and adjacent noncanceroustissues,10normal liver tissues. The expression of RASSF1A mRNA was detected byReal-Time PCR. Then, we evaluated its clinic pathological significance.(2) MS-PCRwas used for analyzing the status of aberrant promoter methylation of RASSF1A in100primary HCC, adjacent normal tissues, six human liver cancer cell lines and10normal liver tissues. Then, we evaluated its clinic pathological significance. RT-PCRwas used to assess reactivation of RASSF1A expression after HCC cell lines treatedwith demethylating agent5’-aza-2’deoxycytideing.Results (1) MS-PCR results revealed that abnormal promoter methylation ofRSSSF1A gene was found in41(63.08%,41/65) cases of HCC,10(15.38%,10/65)cases of adjacent normal tissues, and no abnormal promoter methylation of RSSSF1Agene was found in normal liver tissues, and the difference was statisticallysignificance （x~2=38.092, P<0.001）.The expression of RASSF1A mRNA in HCCtissues of38pairs (58.5%,38/65) was significantly lower than that in adjacentnormal tissues,29out of38(76.32%) HCC cases with lower expression of RASSF1Agene had the promoter hyper-methylation. Statistically significant links were foundbetween low RASSF1A mRNA levels and abnormal promoter methylation（x~2=6.884,P<0.01）.(2) MS-PCR results revealed that abnormal promoter methylation ofRSSSF1A gene was found in69(69%,69/100) cases of HCC,15(15%,15/100) cases of adjacent normal tissues, and no abnormal promoter methylation of RSSSF1A genewas found in normal liver tissues, and the difference was statistically significance（x~2=67.75, P<0.001）. The methylation of RSSSF1A gene was correlation to HbsAg（x~2=11.341, P<0.05）and histological differentiation（x~2=10.575, P<0.05）. Four celllines with abnormal CpG island methylation of RSSSF1A gene were all re-expressedafter treated with5’-Aza-CdR.Conclusions (1)the expression of RSSSF1A was down-regulate in hepatocellularcarcinoma and was significant correlation to gene methylation, the RASSF1A genemay play an important role in the progression of HCC.(2) RSSSF1A gene promotermethylation was significant correlation to HbsAg and histological differentiation andwas one of the most important mechanisms for low expression of RSSSF1A in HCC.Testing for RASSF1A methylation should be useful in early detection and diagnosisof HCC. |
