title: Somatic mutations of K-ras and BRAF in Thai colorectal cancer and their prognostic value.
abstract: BACKGROUND
  The study aimed to determine the incidence of K-ras and BRAF mutations in colorectal cancers (CRCs) in Thai patients and evaluate association with clinicopathological parameters including treatment outcomes in terms of event free survival (EFS).
  
  
  METHODS
  Two-hundred colorectal cancer specimens were collected for studies of K-Ras codon 12, 13 and 61, and BRAF codon 600 by polymerase chain reaction and direct nucleotide sequencing.
  
  
  RESULTS
  The overall incidence of K-Ras mutations in our patients was 23%. K-ras mutation frequencies in CRC stages (AJCC) I, II, III and IV were 6.7%, 16.1%, 23.3% and 26.6%, respectively (p-value>0.05). The three most common mutation forms were G12D, G12V and G13D. K-Ras mutation status was associated with poorer EFS in stage I-III CRCs (p-value 0.03).
  
  
  CONCLUSIONS
  The study found a lower mutation frequency of K-Ras and BRAF compared to reports involving other ethnic groups. However, K-Ras mutations did have a negative prognostic value in early-stage CRCs.
authors.affiliation: Tumor Biology Research Unit, Department of Surgery, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Welawee
authors.initials: W
authors.lastname: Chaiyapan
authors.forename: Pongsanae
authors.initials: P
authors.lastname: Duangpakdee
authors.forename: Teeranut
authors.initials: T
authors.lastname: Boonpipattanapong
authors.forename: Samornmas
authors.initials: S
authors.lastname: Kanngern
authors.forename: Surasak
authors.initials: S
authors.lastname: Sangkhathat
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000235:genetics; D059186:Chemoradiotherapy, Adjuvant; D017024:Chemotherapy, Adjuvant; D003062:Codon; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000628:therapy; D004252:DNA Mutational Analysis; D018572:Disease-Free Survival; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D059645:Mutation Rate; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D016019:Survival Analysis; D013785:Thailand
chemical_list: D003062:Codon; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf