SIRT2 and breast carcinoma: In contrast, SIRT2 was also observed to be tumor-suppressive: Kim et al found that aged SIRT2 knockout mice have increased tumor incidence compared with WT controls 39; Fiskus et al. demonstrated that SIRT2 inhibits the peroxidase activity of peroxiredoxin, and thus sensitizes breast cancer cells to intracellular DNA damage and cell death 40.