In order to further obtain the optimal gene combinations of low dimensions, we selected the combinations of one, two or three genes from the 6 important variables (cyp1a2, cyp2c19, cyp2c9, rac1, diablo, and il6) to establish prediction models for HCC, that is, we ran the random forests algorithm 41 times. This evidence concerns the gene CYP1A2 and hepatocellular carcinoma.