Promoter Methylation Status Of P14^ARF Gene And Expression Of P14^ARF And P53 Protein In Hepatocellular Carcinoma

OBJECTIVE:To investigate promoter methylation status of P14^ARFgene and expression of P14^ARF,P53 protein in hepatocellular carcinoma(HCC), their adjacent liver tissues and noncancerous liver tissues,to analysis the potential relationship among them and clinical parameters,we valued the role of P14^ARFpromoter methylation in carcinogenesis of HCC.METHODS:Methylation specific polymerase chain reaction(MSP)was employed to determine the promoter methylation status of P14^ARF,and the expressions of P14^ARF,P53 protein were analyzed in 50 paired of HCC tissues and their adjacent liver tissues as well as 18 cases of noncancerous liver tissues by immunohistochemestry(IHC),respectively.RESULTS:The positive rate of P14^ARFpromoter methylation in HCC tissues and corresponding adjacent tissues was 28.0%(14/50)and 4.0%(2/50), respectively(P＜0.01),in contrast,all of noncancerous liver tissues were negetive. The positive rate of P14^ARFprotein in tumor tissues(66.0%,33/50)was significantly lower than that in corresponding adjacent nocancinoma tissues (94.0%,47/50)(P＜0.01).As compared with that in the adjacent liver tissues of tumor and noncancerous liver tissues(100%,18/18),the expression of P14^ARF protein was no significantly difference(P＞0.05).The positive rate of P53 protein in HCC tissues(54.0%,27/50)was significantly higher than that in corresponding adjacent nocancinoma tissues(14.0%,7/50)(P＜0.05),there was no significantly difference(P＞0.05)compared with that in the adjacent liver tissues of tumor and noncancerous liver tissues(11.11%,2/18).Promoter methylation and protein expression of P14^ARFwas not correlated with the the clinical stage,the portal vein tumor thrombus,the recurrence of tumor,the presence of extrahepatic metastasis,the diameter of tumor,the number of tumor, the level of alpha-fetoprotein(AFP)in serum.The protein expression of P14^ARFin the HCC tissue was significantly correlated with the differentiation of tumor.On the contrary,P14^ARFpromoter methylation was not.Promoter methylation and protein expression of P14^ARFgene showed a significantly negative correlation(γ=-0.493,P=0.001).The protein expression of P53 in the HCC tissuses was significantly correlated with the portal vein tumor thrombus,the recurrence of tumor,the presence of extrahepatic metastasis and the differentiation of tumor,but had not significantly correlated with the the clinical stage,the diameter of tumor,the number of tumor,the level of alpha-fetoprotein(AFP)in serum.Promoter methylation of P14^ARFgene and the expression of P53 protein showed a significantly positive correlation(γ=0.307, P=0.030).There was a significantly negative relationship of the expression between P14^ARFand P53 proteins(γ=-0.324,P=0.022).CONCLUSION:Promoter methylation is a crucial mechanism of inactivation of P14^ARFgene.Promoter methylation of P14^ARFgene might be involved in carcinogenesis and development of HCC.The inactivation of P14^ARF and overexpression of P53 protein might enhance the hepatocytes proliferation and malignance and play an important role in progress of HCC...