To assess the effects of NAMPT inhibition on cancer metabolism, we used two different cell lines: A2780, a NARPT-negative cell line that can only utilize the NAMPT-mediated nicotinamide pathway for NAD biosynthesis, and HCT-116, a NAPRT-positive cell line that can use both NAMPT-mediated nicotinamide and NAPRT-mediated nicotinic acid pathways for NAD biosynthesis. This evidence concerns the gene NAPRT and cancer.