Downregulation or even loss of Otc and Ass1 are common features of many cancers, limiting aspartate consumption by the urea cycle and instead feeding into de novo nucleotide synthesis associated with tumor growth (Feun et al., 2012, Lam et al., 2011, Lee et al., 2018, Rabinovich et al., 2015). The gene discussed is ASS1; the disease is neoplasm.