ABCB1 and acute lymphoblastic leukemia: Among the ABC transporters involved in MDR, the overexpression of P-glycoprotein (P-gp/ABCB1), multidrug resistance-associated protein 1 (MRP1/ABCC1), breast cancer resistance protein (BCRP/ABCG2), and subfamily C member 5 (ABCC5) had predictive values of treatment failure in patients with acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), Hodgkin lymphoma and DLBCL, respectively [15,16,17,18,19,20].