title: Acquired drug resistance conferred by a KRAS gene mutation following the administration of cetuximab: a case report.
abstract: BACKGROUND
  Although a number of studies have reported acquired drug resistance due to administration of epidermal growth factor receptor antibody inhibitors, the underlying causes of this phenomenon remain unclear.
  
  
  METHODS
  Here we report a case of a 75-year-old man with liver metastasis at 3 years after a successful transverse colectomy to treat KRAS wild-type colorectal cancer. While initial administration of epidermal growth factor receptor inhibitors proved effective, continued use of the same treatment resulted in new peritoneal seeding. An acquired KRAS mutation was found in a resected tissue specimen from one such area. This mutation, possibly caused by administration of epidermal growth factor receptor inhibitors, appears to have conferred drug resistance.
  
  
  CONCLUSIONS
  The present findings suggest that administration of epidermal growth factor receptor inhibitors results in an acquired KRAS mutation that confers drug resistance.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Osumi
authors.affiliation: Department of Gastroenterology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, 3-8-31 Ariake, 135-8550, Koto-ku, Tokyo, Japan. satoshi.matsusaka@jfcr.or.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsusaka
authors.forename: Eiji
authors.initials: E
authors.lastname: Shinozaki
authors.forename: Mitsukuni
authors.initials: M
authors.lastname: Suenaga
authors.forename: Mun
authors.initials: M
authors.lastname: Mingyon
authors.forename: Akio
authors.initials: A
authors.lastname: Saiura
authors.forename: Masashi
authors.initials: M
authors.lastname: Ueno
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Mizunuma
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yamaguchi
mesh_terms: D000368:Aged; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000068818:Cetuximab; D015179:Colorectal Neoplasms / Q000188:drug therapy*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D011905:Genes, ras; D006801:Humans; D008297:Male; D009154:Mutation
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D000068818:Cetuximab