ABCC1 and breast cancer: In breast cancer patients treated with the FEC (5-FU + epirubicin + cyclophosphamide) regimen, MDM2 SNP309 and TP53 R72P genotypes [124], as well as SNPs of the ABCC1/MRP1, UGT2B7, and FGFR4 genes [125], were significantly associated with an increased risk of FN.