Consistent with those studies, the cell cycle signature composed of 13 cell cycle-related genes (TICRR, SPDL1, SGO1, HJURP, CENPA, GINS1, EZH2, BRSK1, NUF2, PLK1, HMMR, E2F2, and CDCA8) possessed superior specificity and sensitivity in predicting the OS of HCC patients. This evidence concerns the gene PLK1 and hepatocellular carcinoma.