Presence of the IL13 rs1800925 T allele was associated with an increased risk of leukopenia (OR = 6.76, 95 % CI = 1.35–33.9, P = 0.020) and also with development of any toxicity > grade 2 (OR = 1.75, 95 % CI = 1.06–2.88, P = 0.028) (Table 3). The gene discussed is IL13; the disease is Decreased total leukocyte count.