title: [Detection of KRAS,NRAS and BRAF gene mutations in colorectal carcinoma].
abstract: OBJECTIVE
  To investigate mutations frequencies of KRAS,NRAS and BRAF genes in colorectal carcinoma.
  
  
  METHODS
  Tissue specimens from 200 colorectal cancer patients at diagnosis were collected and subject to KRAS,NRAS and BRAF mutation analyses by PCR-based direct DNA sequencing targeting exons 2, 3 and 4 of KRAS gene, exons 2, 3 and 4 of NRAS gene and exon 15 of BRAF gene.
  
  
  RESULTS
  Activating mutations were detected in KRAS (44%, 88/200), NRAS (2%, 4/200) and BRAF (5%, 10/200) in this study cohort.Among KRAS mutations, 64.8% (57/88) occurred in codon 12 and 12.5% (11/88) occurred in codon 13. KRAS gene mutation in exon 3 mainly involved codons 59 and 61. KRAS gene mutation in exon 4 mainly involved codons 117 and 146.
  
  
  CONCLUSIONS
  Mutations at exon 2 of KRAS gene have the highest frequency in colorectal carcinoma. Expanding the detection sites of KRAS gene combined with NRAS and BRAF genes may help to identify patients who will most likely benefit from targeted therapies.
authors.affiliation: Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510010, China.
authors.forename: Keping
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510010, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510010, China.
authors.forename: Lixu
authors.initials: L
authors.lastname: Yan
authors.affiliation: Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510010, China.
authors.forename: Xunhua
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510010, China.
authors.forename: Fangping
authors.initials: F
authors.lastname: Xu
authors.affiliation: Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510010, China; E-mail: yanh_liu@163.com.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Liu
mesh_terms: D001483:Base Sequence; D003062:Codon; D015179:Colorectal Neoplasms / Q000235:genetics*; D004252:DNA Mutational Analysis; D005091:Exons; D005260:Female; D011905:Genes, ras; D006801:Humans; D009154:Mutation; D011518:Proto-Oncogene Proteins; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D003062:Codon; D011518:Proto-Oncogene Proteins; D048493:Proto-Oncogene Proteins B-raf