title: Detection of KRAS gene mutations in endoscopic ultrasound-guided fine-needle aspiration biopsy for improving pancreatic cancer diagnosis.
abstract: OBJECTIVE
  Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) is a useful tool in the diagnosis of pancreatic masses. Genetic analysis of these samples could increase the sensitivity and specificity of diagnosis. This study aimed to evaluate the usefulness of a novel method for the detection of mutations in the KRAS (Kirsten rat sarcoma-2 virus) gene for the diagnosis of pancreatic cancer.
  
  
  METHODS
  EUS-FNABs were performed on 82 patients with pancreatic masses, including 54 cases of pancreatic ductal adenocarcinoma and 28 of non-malignant pancreatic masses. The biopsies were histopathologically and cytopathologically evaluated, and the detection of KRAS gene mutations (codons 12 and 13) was performed through peptide nucleic acid-directed polymerase chain reaction clamping and DNA sequencing.
  
  
  RESULTS
  In the pancreatic cancer cases, 88.9% (48/54; 95% confidence interval (CI): 80.5-97.2%) had KRAS mutations, while 61.1% (33/54; 95% CI: 48.1-74.1%) were unequivocally diagnosed by histo/cytopathology. In the indeterminate patients (n=49; diagnosed by EUS-FNA as either insufficient material to make a diagnosis, no malignancy, or suspicion of malignancy), there were 10 cases of pancreatic cancer with low serum carbohydrate antigen 19-9 (CA19-9) (<37 U/l) and 6 of these were KRAS mutations. The sensitivity of detection by KRAS mutations (76.2%) and the combination of KRAS mutations and serum CA19-9 (81%) were significantly higher than for serum CA19-9 alone (52.4%). A logistic regression model showed that the KRAS mutation was significant (odds ratio=5.830; CI: 1.531-22.199, P=0.01), but not serum CA19-9. In the non-malignant pancreatic masses (n=28), KRAS mutations were detected in nine precancerous lesions.
  
  
  CONCLUSIONS
  Our method for the detection of KRAS gene mutations may be useful to supplement histo/cytopathologic evaluations for pancreatic cancer, and is superior to serum CA19-9 in EUS-FNAB histo/cytopathology-indeterminate patients. Results warrant further verification in other patient populations.
authors.affiliation: Department of Gastroenterology, Changhai Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Gao
authors.forename: Yan
authors.initials: Y
authors.lastname: Ren
authors.forename: Junjun
authors.initials: J
authors.lastname: Gu
authors.forename: Yiqi
authors.initials: Y
authors.lastname: Du
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Zhendong
authors.initials: Z
authors.lastname: Jin
authors.forename: Xianbao
authors.initials: X
authors.lastname: Zhan
authors.forename: ZhaoShen
authors.initials: Z
authors.lastname: Li
authors.forename: Haojie
authors.initials: H
authors.lastname: Huang
authors.forename: ShunLi
authors.initials: S
authors.lastname: Lv
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Gong
mesh_terms: D044963:Biopsy, Fine-Needle; D018395:CA-19-9 Antigen / Q000097:blood; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D019160:Endosonography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D018631:ras Proteins / Q000235:genetics*
chemical_list: D018395:CA-19-9 Antigen; D017931:DNA Primers; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins