ABCB1 and renal cell carcinoma: ABCB1 (ATP-binding cassette transporter B1), also known as MDR1 (Multidrug Resistance Protein 1), expressed by CSCs found in ovaries and breast cancers, acute myeloid leukaemia (AML), glioblastoma and renal cell carcinoma, provides drug multi-resistance to anthracyclines actinomycin D, colchicine, etoposide, teniposide, methotrexate, mitomycin C, mitoxantrone, paclitaxel, docetaxel, vincristine and vinblastine [57,58,59,60].