Expression and activity of Fatty Acid Synthase (FASN; the sole enzyme capable of the reductive de novo synthesis of long-chain fatty acids from acetyl-CoA, malonyl-CoA, and nicotinamide adenine dinucleotide phosphate -NADPH-) are extremely low in nearly all nonmalignant adult tissues, whereas FASN is significantly up-regulated or activated in many cancer types. This evidence concerns the gene FASN and cancer.