In breast cancer MCF-7 cells, low levels of hydrogen peroxide and increased superoxide anion concentrations are linked to reduce activity of MnSOD, leading to increased cell proliferation, while the overexpression of MnSOD leads to augmented production of H2O2 and suppression of the malignant phenotype, with inhibition of hypoxic accumulation of hypoxia-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) [109]. Here, SOD2 is linked to breast cancer.