Among the metabolic regulatory factors, fatty acid synthase (FASN) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) are key and rate-limiting regulators to activate de novo biosynthesis of fatty acids/lipids (lipogenesis) and cholesterols (cholesterogenesis), respectively [13,14], and further provide the fundamental components of cell membranes supporting rapid cancer cell growth and inducing the survival signal transduction [15,16,17]. The gene discussed is FASN; the disease is cancer.