title: EUS-FNA mutational analysis in differentiating autoimmune pancreatitis and pancreatic cancer.
abstract: OBJECTIVE
  Autoimmune pancreatitis (AIP) may mimic pancreatic cancer (PC). The detection of DNA mutations in endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) material may improve discrimination between AIP and PC and is the context for this study.
  
  
  METHODS
  In a retrospective study, archived EUS-FNA material from patients with AIP and PC at two centers was analyzed for KRAS mutations and loss-of-heterozygosity analysis involving 18 microsatellite markers. KRAS status and the fractional allelic loss (number of affected microsatellites divided by informative ones) were compared for AIP and PC.
  
  
  RESULTS
  Thirty-two patients with 33 samples were studied. There were 16 patients with AIP (17 samples) and 16 patients with PC. DNA amplification failed in 7 samples. Of 25 patients (26 samples), 14 had AIP (7 male, age 57 ± 17 years; mean ± SD) and 11 had PC (7 male, age 65 ± 14 years; mean ± SD). Cytology results for AIP were inflammatory = 3, inconclusive = 10, suspicious for malignancy = 2 and for PC were malignant = 5, suspicious for malignancy = 4 and inconclusive = 2, respectively. KRAS mutation was detected in none of the AIP cases and 10/11 PC cases (91%, Pearson χ(2) = 22.16, p < 0.001) or 10/16 PC cases (63%) accounting for PC cases with failed DNA amplification. Mean (±SD) fractional allelic loss for the AIP cases (0.16 ± 0.15) was not significantly different from the PC cases (0.26 ± 0.19).
  
  
  CONCLUSIONS
  A KRAS mutation in EUS/FNA material from a pancreatic mass is associated with malignancy and may help discriminate from benign conditions such as AIP.
authors: University of Pittsburgh Medical Center, Pittsburgh, Pa., USA. khalida@upmc.edu
authors: Asif
authors: A
authors: Khalid
authors: John
authors: J
authors: Dewitt
authors: N Paul
authors: NP
authors: Ohori
authors: Jey-Hsin
authors: JH
authors: Chen
authors: Kenneth E
authors: KE
authors: Fasanella
authors: Michael
authors: M
authors: Sanders
authors: Kevin M
authors: KM
authors: McGrath
authors: Marina
authors: M
authors: Nikiforova
mesh_terms: D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D044963:Biopsy, Fine-Needle / Q000379:methods; D004252:DNA Mutational Analysis; D019160:Endosonography; D005260:Female; D011905:Genes, ras / Q000235:genetics; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology; D010195:Pancreatitis / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D012189:Retrospective Studies