TP53 and colonic neoplasm: While, the CBS inhibitor aminooxyacetic acid (AOAA) is also involved in regulating ROS levels and P53 activation 12, 16.Considering the antioxidant effect of H2S and the pivotal role of increased ROS in mediating the apoptosis induced by OXA, inhibition of H2S synthesis might sensitize colon cancer cells to OXA.