(21) Ala → pyruvate, catalyzed by L-amino-acid oxidases (LAAO) (Nakano et al., 1967): Several mammalian LAAOs have been described, of which the enzyme “interleukin-4 induced gene 1” (IL4I1) is the best characterized (Castellano and Molinier-Frenkel, 2017); IL4I1 expression was reported to be associated with poor prognosis in human breast cancers (Finak et al., 2008). The gene discussed is IL4I1; the disease is breast cancer.