title: RAS status in Korean patients with stage III and IV colorectal cancer.
abstract: BACKGROUND
  KRAS mutations are common and clearly contribute to malignant progression. The frequency of NRAS mutations and their relationship to clinical, pathologic, and molecular features remains unclear.
  
  
  METHODS
  We evaluated 130 colorectal tumors for mutations in KRAS and NRAS gene. We tested for mutations in codons 61 and 146 of KRAS and codons 12, 13, 59, 61 and 146 of NRAS. Mutation status was determined by targeted dideoxy sequencing.
  
  
  RESULTS
  Among the analyzed primary tumors, 36.2% had KRAS mutation. Of the 83 KRAS codon 12 and 13 wild-type patients, 7.2% had KRAS codon 61, 146 or NRAS. 40.7% harbored any RAS mutation.
  
  
  CONCLUSIONS
  The frequency of other RAS (NRAS and KRAS exon 3, 4) activating mutations in colorectal cancers is relatively low in Korean colorectal cancer patients.
authors.affiliation: Department of Surgery, Gil Medical Center, Gachon University School of Medicine, 1198 Guwol-dong, Namdong-gu, Incheon, 405-760, Korea, lws@gilhospital.com.
authors.forename: W-S
authors.initials: WS
authors.lastname: Lee
authors.forename: J N
authors.initials: JN
authors.lastname: Lee
authors.forename: J-H
authors.initials: JH
authors.lastname: Baek
authors.forename: Y H
authors.initials: YH
authors.lastname: Park
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000556:secondary; D002288:Adenocarcinoma, Mucinous / Q000235:genetics* / Q000556:secondary; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics; D018279:Carcinoma, Signet Ring Cell / Q000235:genetics* / Q000556:secondary; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D020558:GTP Phosphohydrolases / Q000235:genetics*; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009367:Neoplasm Staging; D011379:Prognosis; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*; D056910:Republic of Korea
chemical_list: D014408:Biomarkers, Tumor; C117307:KRAS protein, human; D008565:Membrane Proteins; D020558:GTP Phosphohydrolases; C579846:NRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras)