ABCB1 and leukemia: It was in fact seen that Carfilzomib showed relevant activity in the majority of ALL cell lines except for the P-glycoprotein-positive t (17, 19) ALL cell lines, and the knockout of the IKZF1 gene was associated with a favorable response to Carfilzomib treatment (136), making the association of Carfilzomib with the current chemotherapy protocols a new therapeutic option for refractory ALL with P-glycoprotein-negative leukemia cells.