APOB and hepatocellular carcinoma: The total somatic mutations were no significant differences among subtypes (P = 0.051, Kruskal-Wallis test), while detailed investigation showed that in the top 20 most frequently mutated genes in HCC, 8 of them (TP53, CTNNB1, PCLO, OBSCN, AXIN1, CSMD3, APOB, and CACNA1E) showed significant variations among subtypes (Fig. 4e).