RASSF1 and hepatocellular carcinoma: We found that the frequency of RASSF1A gene promoter hypermethylation was remarkably related to a high HCC risk in the overall comparison (odds ratio [OR] = 6.87, 95% confidence interval [CI] = 4.98–9.50, P < 0.001), and moderate heterogeneity was present (I2 = 64.1%, P = 0.000).