The risk of anemia present at four or more cycles of FAC treatment (recurrent anemia) was determined by the occurrence of ABCC1 rs129081 genotype GG (OR 8.02; 0.02–0.63; p = 0.012), ERCC1 rs1046282 heterozygote TC (OR 5.24; 1.0–6.99; p = 0.047), and UGT2B4 rs1131878 variant AA (OR 8.91; 0.01–0.94; p = 0.043) (Table 1). This evidence concerns the gene ERCC1 and anemia (phenotype).