DPYD and Decreased total leukocyte count: The occurrence of leukopenia symptoms in the two first FAC chemotherapy cycles (early leukopenia) was determined by DPYD rs291583 variant GG (OR 2.25; 1.25–4.05; p = 0.006) and AKR1C3 rs3209896 genotypes AA and GG (OR 1.77; 1.08–2.89; p = 0.021) (Table 2).