To test whether low dose of palmitate (50 ~ 100 μM) affects the molecular clock function in hepatocytes, we examined the effect of palmitate treatment on the activity of a mouse Per2 promoter-driven luciferase reporter (Per2-luc) in a mouse hepatoma Hepa1c1c-7 (Hepa1) cell line. This evidence concerns the gene PER2 and hepatocellular carcinoma.