A comparison of the methylation level between stage I and stage II HCC (Figure 3) revealed that 5 and 2 genes were differentially methylated in the ErbB (ATK1, PTK2, CAMK2D, CRK, and MYC) and MAPK pathways (TNFRSF1A and NTRK2), respectively. Here, PTK2 is linked to hepatocellular carcinoma.