title: K-ras mutational status predicts poor prognosis in unresectable pancreatic cancer.
abstract: OBJECTIVE
  To determine the prognostic value of K-ras mutations in plasma DNA of unresectable pancreatic cancer patients.
  
  
  METHODS
  Blood samples were collected from 91 patients with unresectable pancreatic cancer prior to treatment. K-ras gene was amplified from the circulating plasma DNA. Mutations were detected by direct sequencing. The relationship between the types of K-ras gene and prognosis of unresectable pancreatic cancer was evaluated.
  
  
  RESULTS
  K-Ras codon 12 mutations were found in 30 of 91(33%) plasma DNA samples, 17mutations were c.35G>A (p.G12D), 11 were c.35G>T (p.G12V) and only 2 were c.34G>C (p.G12R)). K-ras codon 12 mutations could significantly reflect the clinical parameters, including TNM tumor staging (P=0.033) and liver metastasis (P=0.014). The median survival time of patients with K-ras mutations was shorter than that of patients with wild-type K-ras gene (3.9 months vs. 10.2 months, P<0.001). K-ras codon 12 mutation from plasma DNA was an independent negative prognostic factor for survival (hazard ratio, 7.39; 95% confidence interval, 3.69-14.89).
  
  
  CONCLUSIONS
  K-ras mutation in plasma DNA is a predictive biomarker for a poor prognosis of unresectable pancreatic cancer patients.
authors.affiliation: Department of Hepatobiliary & Pancreatic Oncology, Cancer Hospital, Fudan University, Shanghai, China.
authors.forename: H
authors.initials: H
authors.lastname: Chen
authors.forename: H
authors.initials: H
authors.lastname: Tu
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Meng
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.forename: P
authors.initials: P
authors.lastname: Wang
authors.forename: L M
authors.initials: LM
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People / Q000235:genetics*; D002681:China; D003062:Codon; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D011905:Genes, ras; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000556:secondary; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009154:Mutation; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy*; D011237:Predictive Value of Tests; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D003062:Codon; D004273:DNA, Neoplasm