SIRT1 and breast cancer: Given that SIRT1 rs3758391 TT, rs12778366 TT and rs3740051 combined GG and AG genotypes were significantly associated with breast cancer and showed higher SIRT1 levels compared to other genotypes, we could speculate that the association of SIRT1 rs3758391 T allele, rs12778366 T allele and, to a lesser extent, rs3740051 G allele with a higher breast cancer risk may be explained by higher levels of SIRT1 expression, possibly having an impact on histone deacetylation.