MDM2 and hepatocellular carcinoma: The results of pooling all studies showed that the MDM2 SNP309 polymorphism was associated with increased HCC risk in all genetic models (G vs. T: OR = 1.371, 95%CI: 1.153–1.631, P = 0.000; GG vs. TT: OR = 1.831, 95%CI: 1.300–2.579, P = 0.001, Figure 1; TG vs. TT: OR = 1.416, 95%CI: 1.126–1.780, P = 0.003; GG vs. TG+TT: OR = 1.398, 95%CI: 1.148–1.703, P = 0.001; GG+TG vs. TT: OR = 1.577, 95%CI: 1.209–2.058, P = 0.001).