title: Mutation Analysis of KRAS and BRAF Genes in Metastatic Colorectal Cancer: a First Large Scale Study from Iran.
abstract: BACKGROUND
  The investigation of mutation patterns in oncogenes potentially can make available a reliable mechanism for management and treatment decisions for patients with colorectal cancer (CRC). This study concerns the rate of KRAS and BRAF genes mutations in Iranian metastatic colorectal cancer (mCRC) patients, as well as associations of genotypes with clinicopathological features.
  
  
  METHODS
  A total of 1,000 mCRC specimens collected from 2008 to 2012 that referred to the Mehr Hospital and Partolab center, Tehran, Iran enrolled in this cross sectional study. Using HRM, Dxs Therascreen and Pyrosequencing methods, we analyzed the mutational status of KRAS and BRAF genes in these.
  
  
  RESULTS
  KRAS mutations were present in 33.6% cases (n=336). Of KRAS mutation positive cases, 85.1% were in codon 12 and 14.9% were in codon 13. The most frequent mutation at KRAS codon 12 was Gly12Asp; BRAF mutations were not found in any mCRC patients (n=242). In addition, we observed a strong correlation of KRAS mutations with some clinicopathological characteristics.
  
  
  CONCLUSIONS
  KRAS mutations are frequent in mCRCs while presence of BRAF mutations in these patients is rare. Moreover, associations of KRAS genotypes with non-mucinous adenocarcinoma and depth of invasion (pT3) were remarkable.
authors.affiliation: Gastrointestinal and Liver Diseases Research Center, Firoozgar Hospital, Iran University Of Medical Sciences, Tehran, Iran E-mail : n_rakhshani@yahoo.com.
authors.forename: Aghigh
authors.initials: A
authors.lastname: Koochak
authors.forename: Nasser
authors.initials: N
authors.lastname: Rakhshani
authors.forename: Mohammad Hadi
authors.initials: MH
authors.lastname: Karbalaie Niya
authors.forename: Fahimeh Safarnezhad
authors.initials: FS
authors.lastname: Tameshkel
authors.forename: Masoud Reza
authors.initials: MR
authors.lastname: Sohrabi
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Babaee
authors.forename: Hamid
authors.initials: H
authors.lastname: Rezvani
authors.forename: Babak
authors.initials: B
authors.lastname: Bahar
authors.forename: Farid
authors.initials: F
authors.lastname: Imanzade
authors.forename: Farhad
authors.initials: F
authors.lastname: Zamani
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Khonsari
authors.forename: Hossein
authors.initials: H
authors.lastname: Ajdarkosh
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Hemmasi
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000453:epidemiology / Q000235:genetics* / Q000556:secondary; D014408:Biomarkers, Tumor / Q000235:genetics*; D018279:Carcinoma, Signet Ring Cell / Q000453:epidemiology / Q000235:genetics* / Q000556:secondary; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D003430:Cross-Sectional Studies; D004252:DNA Mutational Analysis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D059645:Mutation Rate; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; C117307:KRAS protein, human; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras)