ABCG2 and cancer: P-gp, MRP1, and BCRP export a broad range of structurally and mechanistically unrelated cancer chemotherapeutics, covering almost the whole range of the antineoplastic approved for clinical use, including: vinca alkaloids, podophyllotoxins, taxanes, tyrosine kinase inhibitors, camptothecin analogs, antitumor antibiotics, anthracyclines, antimetabolite, anthracenes and epipodophyllotoxins (Figure 2) [31].