However, in other types of cancer, such as small intestine adenocarcinoma (24) and hepatocellular carcinoma (HCC) (25), the levels of CPS1 are downregulated, which associates with decreased survival and an increase of CAD expression, resulting in the reuse of ammonia for the synthesis of glutamine as a means to initiate de novo pyrimidine synthesis (21). The gene discussed is CPS1; the disease is cancer.