ABCG2: structure, function and role in drug response

Expert Opin Drug Metab Toxicol. 2008 Jan;4(1):1-15. doi: 10.1517/17425255.4.1.1.


ABCG2 was discovered in multi-drug-resistant cancer cells, with the identification of chemotherapeutic agents, such as mitoxantrone, flavopiridol, methotrexate and irinotecan as substrates. Later, drugs from other therapeutic groups were also described as substrates, including antibiotics, antivirals, HMG-CoA reductase inhibitors and flavonoids. An expanding list of compounds inhibiting ABCG2 has also been generated. The wide variety of drugs transported by ABCG2 and its normal tissue distribution with highest levels in the placenta, intestine and liver, suggest a role in protection against xenobiotics. ABCG2 also has an important role in the pharmacokinetics of its substrates. Single nucleotide polymorphisms of the gene were shown to alter either plasma concentrations of substrate drugs or levels of resistance against chemotherapeutic agents in cell lines. ABCG2 was also described as the determinant of the side population of stem cells. All these aspects of the transporter warrant further research aimed at understanding ABCG2's structure, function and regulation of expression.

Publication types

  • Review

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily G, Member 2
  • ATP-Binding Cassette Transporters / biosynthesis
  • ATP-Binding Cassette Transporters / genetics
  • ATP-Binding Cassette Transporters / physiology*
  • Animals
  • Antineoplastic Agents / therapeutic use
  • Drug Resistance, Multiple / drug effects
  • Drug Resistance, Multiple / genetics*
  • Drug Resistance, Neoplasm / drug effects
  • Drug Resistance, Neoplasm / genetics*
  • Humans
  • Neoplasm Proteins / biosynthesis
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / physiology*
  • Neoplasms / drug therapy*
  • Neoplasms / genetics*
  • Polymorphism, Single Nucleotide / genetics
  • Protein Conformation
  • Terminology as Topic


  • ABCG2 protein, human
  • ATP Binding Cassette Transporter, Subfamily G, Member 2
  • ATP-Binding Cassette Transporters
  • Antineoplastic Agents
  • Neoplasm Proteins