The results indicate that all 20 genes with the most significant differential expression in the cell cycle pathway (Ccna2, Mcm5, Espl1, Bub1, Bub1b, Cdc6, Cdc25c, Ccne2, Mad2l1, Plk1, Ttk, Mcm6, Ccnb1, Mcm2, Pkmyt1, Rbl1, Ccne1, Cdk1, Ccnb2, Mcm3) are markedly overexpressed in HCC patients (Fig. 3E). The gene discussed is PLK1; the disease is hepatocellular carcinoma.