Mitochondrial superoxide generation stimulates MnSOD expression in cancer cells.44 We investigated MnSOD expression in MCF-10A cells and found that overexpressing MCT-1 increased MnSOD but decreased p53 levels (Figure 4a), but knockdown of p53 (shp53) further increased the amount of MnSOD in MCT-1 oncogenic cells. This evidence concerns the gene SOD2 and cancer.