SIRT1 and ovarian cancer: Cisplatin-resistant ovarian cancers increase BRCA1, SIRT1, and EGFR levels compared with those in cisplatin-sensitive ovarian cancers. Decreased nicotinamide adenine dinucleotide (NAD)-mediated SIRT1 activity, decreased EGFR levels, significantly elevated SIRT1 levels, and BRCA1 activation are associated with hypomethylation in the BRCA1 promoter