Since NCX4040 generates ROS in tumor cells we chose these ovarian cancer cell lines (OVCAR-8 and NCI/ADR-RES) to decipher the mechanisms of NCX4040 as NCI/ADR-RES cells show resistance to free radical generating drugs, including adriamycin due to higher expressions of SOD, catalase, glutathione-dependent peroxidase and transferase in NCI/ADR-RES cells [38,39]. Here, SOD1 is linked to ovarian cancer.