SOD2 and cancer: In cancer cells the decrease in mitochondrial metabolism (i.e., decreased GO) would result in decreased ETC activity and decreased mROS (i.e., mostly superoxide) and ultimately decreased H2O2 production via the dismutation of superoxide (although the role of manganese superoxide dismutase (MnSOD) in cancer remains controversial and only partially explored; Holley et al., 2012).