IL4I1 and leukemia: It is possible that changes on FAD site could affect the cytotoxic activity of LAAO on cancer cells since the production of H2O2 from the enzyme was identified to contribute towards cytotoxicity and apoptotic activity in several cell lines, such as HL60 (human promyelocytic cell), HeLa (cervical cancer cells), MM6 (human monocytic cell), and human leukemia T-cells [7,8,9,23].