GSTM1 and breast cancer: Risk of FAC-related anemia of any grade was elevated by polymorphic allele C of p.Asn118= (rs11615) variant in ERCC1 gene, common homozygote GG of ABCC2 p.Val417Ile (rs2273697) polymorphism, presence of both GSTT1 and GSTM1 genes and triple-negativity of breast cancer.