We have previously reported that cancer cells produce larger amounts of ROS than normal cells do, and MnSOD expression in cancer cells suppress ROS production.(24) Since MnSOD is specifically able to scavenge ROS derived from mitochondria, using MnSOD overexpressing cancer cells (RGK MnSOD) allows direct examination of the influence of mitROS on iron uptake and cell proliferation in cancer cells. This evidence concerns the gene SOD2 and cancer.