IL4I1 and cancer: Indeed, snake LAAOs rapidly and strongly produce more H2O2 than human LAAOs (encoded by interleukin-4-induced gene 1, IL4I1), but the human LAAOs induced higher indole-3-pyruvate (I3P) that promotes cancer survival41. Due to the differences in LAAOs between snakes and other hosts, l-lysine and l-arginine which were possibly more specific to OH-LAAO were used in this study.