SIRT6 and breast cancer: High levels of SIRT6 promote inactivation of many tumor suppressor proteins such as p53 that is mutated in six out of the eight tested breast cancer cell lines including triple negative cells, whereas low levels of SIRT6 increase the expression of cellular myelocytomatosis (c-MYC) and hypoxia-inducible factor (HIF1), resulting in accelerated cellular proliferation and glycolysis, respectively [43].