The higher risk for development of early leukopenia was found to be significantly associated with NUDT15*3 carriers (OR 15.31; 95% CI 9.65–24.27, I2 = 63.6%) (Figure 2) compared to those patients with late onset (OR 4.9; 95% CI 3.56–6.74, I2 = 47.4) (Supplementary Figure S1). This evidence concerns the gene NUDT15 and Decreased total leukocyte count.