Promoter methylation of E-cadherin in hepatocellular carcinomas and dysplastic nodules

In order to clarify the significance of E-cadherin methylation in multistep hepatocarcinogenesis, we examined the methylation status of the E-cadherin promoter region, using methylation-specific polymerase chain reaction in 64 hepatocellular carcinomas (HCCs) and 13 dysplastic nodules (DNs), and correlated these results with E-cadherin protein expression and clinicopathologic factors of HCCs. Promoter methylation was detected in 1 of 13 (7.7%) DNs, in 5 of 13 (38.5%) Edmondson and Steiner grade I HCCs, and in 27 of 51 (52.9%) grade II or III HCCs, and a significant correlation was observed between the methylation status and the stepwise progression of hepatocarcinogenesis (p=0.004). Reduced E-cadherin immunoreactivity was found in 18 of 64 (28%) HCCs, but in none of DNs. E-cadherin methylation status in HCCs was significantly correlated with microvascular invasion (p=0.02) and tumor recurrence (p=0.04), but not with reduced E-cadherin immunoreactivity. The Kaplan-Meier method showed that methylation status did not have a significant influence on the recurrence-free survival of HCC patients (p=0.15). Our results indicate that methylation of the E-cadherin promoter region is a frequent event in HCC, which may play an important role in the stepwise progression of hepatocarcinogenesis. And the promoter methylation of E-cadherin in HCC was found to be significantly correlated with microvascular invasion and recurrence.