ABCB1 and acute lymphoblastic leukemia: In patients with primary ALL, moderate correlations between MDR1 mRNA expression and therapy response (r = 0.67) and weak correlations between the same parameter and sensitivity to daunorubicin, cytarabine, and vincristine (r = 0.14, r = 0.09, and r = 0.10, respectively) were found (Figure 3B, Table S9).