IL4I1 and cancer: The cytotoxic activity of snake venom LAOs has been linked to the production of H2O2, which accumulates on the cell surface and triggers oxidative stress in cancer cells leading to apoptosis.13,29 An increasing accumulation of intracellular H2O2 was found in ApLAO- or CgLAO-treated Jurkat cells, which was probably related to the LAO activity.