The membrane-associated protein encoded by this gene is included in the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the White subfamily. Alternatively referred to as the breast cancer resistance protein, this protein functions as a xenobiotic transporter which may play a role in multi-drug resistance to chemotherapeutic agents including mitoxantrone and camptothecin analogues. Early observations of significant ABCG2-mediated resistance to anthracyclines were subsequently attributed mutations encountered in vitro but not in nature or the clinic. Significant expression of this protein has been observed in the placenta, and it has been shown to have a role in protecting the fetus from xenobiotics in the maternal circulation.
↑Allikmets R, Gerrard B, Hutchinson A, Dean M (Feb 1997). "Characterization of the human ABC superfamily: isolation and mapping of 21 new genes using the expressed sequence tags database". Hum Mol Genet. 5 (10): 1649–55. doi:10.1093/hmg/5.10.1649. PMID8894702.
Sugimoto Y, Tsukahara S, Ishikawa E, Mitsuhashi J (2005). "Breast cancer resistance protein: molecular target for anticancer drug resistance and pharmacokinetics/pharmacodynamics". Cancer Sci. 96 (8): 457–65. doi:10.1111/j.1349-7006.2005.00081.x. PMID16108826.
Ishikawa T, Tamura A, Saito H, et al. (2006). "Pharmacogenomics of the human ABC transporter ABCG2: from functional evaluation to drug molecular design". Naturwissenschaften. 92 (10): 451–63. doi:10.1007/s00114-005-0019-4. PMID16160819.