title: Pharmacogenetics of ABCG2 and adverse reactions to gefitinib.
abstract: Gefitinib is an inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase with activity in non-small-cell lung cancer. Diarrhea and skin toxicity are prominent gefitinib-related adverse events that potentially limit its use. Gefitinib is a substrate for ABCG2 (ABCP, BCRP, MXR), a polymorphic efflux transporter protein that is highly expressed in the intestines and liver. Here we investigated associations between allelic variants of EGFR, ABCG2, and the transporter protein ABCB1 with diarrhea and skin toxicity in gefitinib-treated patients. One variant, a common functional single-nucleotide polymorphism (SNP) in the ABCG2 gene, was associated with diarrhea in 124 patients treated with oral gefitinib 250 mg once daily; seven (44%) of 16 patients heterozygous for ABCG2 421C>A (Q141K) developed diarrhea, versus only 13 (12%) of 108 patients homozygous for the wild-type sequence (P = .0046). However, this SNP was not associated with skin toxicity (P = .99). The finding suggests that patients with reduced ABCG2 activity due to a common genetic variant are at increased risk for substrate drug-induced diarrhea, with implications for optimizing treatment with such agents.
authors.affiliation: The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA.
authors.forename: George
authors.initials: G
authors.lastname: Cusatis
authors.forename: Vanesa
authors.initials: V
authors.lastname: Gregorc
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Anna
authors.initials: A
authors.lastname: Spreafico
authors.forename: Roxann G
authors.initials: RG
authors.lastname: Ingersoll
authors.forename: Jaap
authors.initials: J
authors.lastname: Verweij
authors.forename: Vienna
authors.initials: V
authors.lastname: Ludovini
authors.forename: Eugenio
authors.initials: E
authors.lastname: Villa
authors.forename: Manuel
authors.initials: M
authors.lastname: Hidalgo
authors.forename: Alex
authors.initials: A
authors.lastname: Sparreboom
authors.forename: Sharyn D
authors.initials: SD
authors.lastname: Baker
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000970:Antineoplastic Agents / Q000009:adverse effects*; D003967:Diarrhea / Q000139:chemically induced; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D000077156:Gefitinib; D014644:Genetic Variation; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics*; D009369:Neoplasms / Q000188:drug therapy*; D011110:Polymorphism, Genetic; D011799:Quinazolines / Q000009:adverse effects*; D012867:Skin / Q000473:pathology
chemical_list: C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000970:Antineoplastic Agents; D009363:Neoplasm Proteins; D011799:Quinazolines; D066246:ErbB Receptors; D000077156:Gefitinib