MRP1 has been found to be overexpressed in vitro in a number of drug-selected cell lines including leukemia, lung, breast, bladder, prostate, and cervical cancer cell lines, as well as in vivo in human patients with leukemia and a variety of solid tumors, including gastrointestinal tract, (non-small cell) lung, breast, ovarian and prostate carcinomas and melanoma [92]. This evidence concerns the gene ABCC1 and leukemia.