Drug-resistance related protein, its expression is associated with the chemotherapy resistant and neoplastic phenotype. May also be linked to the malignant phenotype. Weakly expressed in kidney. Expressed in various tumor cell lines including carcinomas, myeloid and lymphoid malignancies, melanomas and prostate cancer. Overexpressed in taxol-resistant breast cancer line MDA 435TR and the doxorubicin-resistant multiple myelanoma lines RPMI-8226/Dox40 and RPMI-8226/MDR10V.