CLOCK and hepatocellular carcinoma: For example, Npas2, a core clock gene involved in the positive limb of the clock and active mainly during the day, directly upregulates genes critical for glycolysis such as HIF1α, Glut1, Hk2, Aldoa, and Eno2 and downregulates Pgc1α in hepatocellular carcinoma [114], which accelerated the growth and metastasis of these tumors in vivo (Fig. 2).