DAPK1 and hepatocellular carcinoma: For 17 genes reported in at least three studies between HCC tumor tissues and normal tissues (Table 2), no evidence of statistical heterogeneity was observed for 11 genes, including p16 (I2 = 13%), RASSF1A (I2 = 37%), CDH1 (I2 = 17%), p15 (I2 = 0%), RUNX3 (I2 = 0%), MGMT (I2 = 36%), SFRP1 (I2 = 0%), PRDM2 (I2 = 0%), DAPK1 (I2 = 0%), RARβ (I2 = 14%) and p73 (I2 = 0%).