Overexpression of BCRP and P-gp has been related to reduced clinical response and MDR in chronic lymphocytic leukemia, multiple myeloma, ALL, metastatic breast cancer, and AML.5 Furthermore, P-gp was found to have an important role in MDR in malignancy cells, facilitating intracellular chemotherapeutic drug efflux and suppressing tumor necrosis factor (TNF). Here, PGP is linked to acute lymphoblastic leukemia.