High Rate of P16 Methylation Associated with Hepatitis B Virus Infection in Hepatocellular Carcinoma

Abstract

Objective: To investigate the potential linkage between high rate of p16 methylation and hepatitis B virus (HBV) infection, methylation status of p16, HBV infection markers in serum and HBV-DNA replication level in cancerous and non-cancerous tissue of 32 cases of hepatocellular carcinomas (HCC) with HBV infection and 12 HCCs without HBV infection were examined. Methods: p16 methylation was detected with methylation-specific polymerase Chain reaction (PCR), and HBV markers were examined with real-time PCR and immunologic method. Results: Methylation of p16 promoter was found in 31 (70.5%) of 44 cancerous tissues of HCC, 2 (16.7%) of 12 HCC without HBV infection, 29 (90.6%) of 32 HCCs with HBV infection marker. p16 methylation was detected in 5 (83.3%) of 6 HCCs positive for HBsAg and HBeAg, 17 (94.4%) of 18 HCCs positive for HBsAg and negative for HBeAg, 7/8 (87.5%) of HCCs positive for other HBV infection markers, such as HBsAB, HBcAb, HBeAb. p16 methylation products were also found in non-cancerous tissues of 4 cases of HCCs with HBV infection, not detected in non-cancerous tissues without HBV infection. HBV-DNA was detected in cancerous tissues of 29/32 (90%) HCCs with HBV infection. Surprisingly, Methylation product of p16 promoter was found in all cases (29/29) of HCCs with detectable HBV-DNA in neoplastic tissue. Conclusion: Persistent HBV infection may promote p16 hypermethylation, suggesting that HBV, via enhancing the aberrant methylation of p16, indirectly involved in development of HCC.