Key enzymes related to fatty acid synthesis and cholesterol synthesis, for example, long-chain acyl-CoA synthetase (ASCL), 1-aminocyclopropane-1-carboxylic acid (ACC), Fatty acid synthase (FASN), stearoyl-CoA desaturase (SCD), 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMGCR), Serine Proteinase (SM), several studies have shown the high expression of critical enzymes in cancer cells and promote the development of tumor (43–51). The gene discussed is FASN; the disease is cancer.