ABCB1 and leukemia: This overexpression correlates with increased multidrug resistance protein 1 (MDR1) gene expression, which encodes the protein P-glycoprotein 1 (P-gp) (also ATP-binding cassette sub-family B member 1, ABCB1), leading to multidrug resistance for example against vinblastin (human cervix carcinoma KB-3-1 cells; Hela derivatives), vincristine (human leukemia (HL)-60 cells) and adriamycin (human colon cancer cells SW620).