We also observed that KEGG pathway categories Cell cycle, Pathways in cancer, HTLV-I infection, Hepatitis B, and p53 signaling pathway were significantly enriched by the hHubGs-sets {CCNB2, CCNB1, CHEK1, CDK2, CDK1}, {CDK2}, {CHEK1}, {CDK2}, and {CCNB2, CCNB1, CHEK1, CDK2, CDK1}, respectively. This evidence concerns the gene CDK2 and hepatitis B virus infection.