CYP2A7 and Decreased total leukocyte count: Area under the curve (AUC) for 6MP-induced leukopenia with this variant reached 0.82 [95% confidence interval (CI), 0.75–0.90], compared with 0.58 (95% CI, 0.52–0.63) for rs1142345 in TPMT and 0.63 (95% CI, 0.55–0.72) for rs73032311 in CYP2A7. After combining these three SNPs, the prediction accuracy increased with AUC of 0.87 (95% CI, 0.81–0.93) (Figure 1A).