title: Imatinib efficacy by tumor genotype in Korean patients with advanced gastrointestinal stromal tumors (GIST): The Korean GIST Study Group (KGSG) study.
abstract: OBJECTIVE
  To assess the efficacy of imatinib for different tumor genotypes in Korean patients with advanced gastrointestinal stromal tumors (GIST).
  
  
  METHODS
  Clinical data were collected from 370 consecutive patients with locally advanced unresectable, metastatic, or recurrent GIST treated with imatinib 400 mg/day between August 2001 and December 2007 at 20 Korean institutions. Tumor genotypes were determined for 290 patients by direct DNA sequencing of KIT exons 9, 11, 13, and 17, and PDGFRA exons 12, 14, and 18.
  
  
  RESULTS
  Of 290 patients assessed for genotype, 261 (90.0%) had mutations in KIT: 222 (76.6%) in exon 11, 35 (12.1%) in exon 9 and two each (0.7%) for exons 13 and 17. Four patients (1.4%) had mutations in the PDGFRA gene: one in exon 12, and three in exon 18. Twenty-five patients (8.6%) had no detectable mutations. The best responses of the 235 patients with measurable lesions were: 15 complete response (6.4%), 126 partial response (53.5%), 86 stable disease (36.6%), and eight progressive disease (3.4%). Patients with KIT exon 9 mutations, compared with patients with KIT exon 11 mutations, had a lower objective response rate (36.7% vs. 63.6%, p = 0.007) and a shorter progression-free survival (median 28.7 months vs. 49.4 months, p = 0.001). No statistical difference in overall survival was observed between these genotypes.
  
  
  CONCLUSIONS
  This study confirms that imatinib efficacy is dependent on genotype in Korean GIST patients, consistent with results demonstrated by Western patients with GIST.
authors.affiliation: Division of Hematology/Oncology, Department of Internal Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Kang
authors.forename: Min-Hee
authors.initials: MH
authors.lastname: Ryu
authors.forename: Kyoung-Mee
authors.initials: KM
authors.lastname: Kim
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Park
authors.forename: Jene
authors.initials: J
authors.lastname: Choi
authors.forename: Baek-Yeol
authors.initials: BY
authors.lastname: Ryoo
authors.forename: Woo Ho
authors.initials: WH
authors.lastname: Kim
authors.forename: Seock-Ah
authors.initials: SA
authors.lastname: Im
authors.forename: Yung-Jue
authors.initials: YJ
authors.lastname: Bang
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Park
authors.forename: Jae-Hyuk
authors.initials: JH
authors.lastname: Lee
authors.forename: Ik Joo
authors.initials: IJ
authors.lastname: Chung
authors.forename: Han-Ik
authors.initials: HI
authors.lastname: Bae
authors.forename: Jong Gwang
authors.initials: JG
authors.lastname: Kim
authors.forename: Kyung Hee
authors.initials: KH
authors.lastname: Lee
authors.forename: Hong Suk
authors.initials: HS
authors.lastname: Song
authors.forename: Hyuk-Chan
authors.initials: HC
authors.lastname: Kwon
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Baek
authors.forename: Dong Bok
authors.initials: DB
authors.lastname: Shin
authors.forename: Kyoung Eun
authors.initials: KE
authors.lastname: Lee
authors.forename: Yoon-Koo
authors.initials: YK
authors.lastname: Kang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D005091:Exons / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy* / Q000235:genetics* / Q000401:mortality; D006801:Humans; D000068877:Imatinib Mesylate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000235:genetics / Q000401:mortality; D009367:Neoplasm Staging; D010879:Piperazines / Q000627:therapeutic use*; D011379:Prognosis; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D011743:Pyrimidines / Q000627:therapeutic use*; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics*; D012189:Retrospective Studies; D015996:Survival Rate; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha