Herein, we investigated the possible roles of 13 core circadian clock genes in HCC, including ARNTL, CLOCK, CRY1, CRY2, DBP, NR1D1, NR1D2, NPAS2, PER1, PER2, PER3, RORA, and TIMELESS. This evidence concerns the gene CRY1 and hepatocellular carcinoma.