from NCBI SIRT1, a NAD+-dependent histone/protein deacetylase, has been emerging as a crucial regulator of assorted physiological events through deacetylation of various proteins related to apoptosis, DNA repair, and metabolism. SIRT1 is also involved in tumorigenesis; but it is still under much debate whether SIRT1 stimulates or suppresses carcinogenic processes. SIRT1 inhibits inflammation and activities of transcription factors that exacerbate carcinogenesis. Moreover, SIRT1 contributes to preservation of genomic stability. Thus, SIRT1 takes part in prevention, retardation, and suppression of carcinogenesis. SIRT1 is supposed to be underexpressed in tumors if it is indeed a tumor suppressor. Contrary to this supposition, substantial proportions of human cancer specimens have shown overexpression of SIRT1. SIRT1 aggravates inflammation, inactivates tumor suppressors, and, concomitantly, activates protooncogenes. In addition, SIRT1 promotes cancer cell proliferation, invasion, m...