title: Analysis of K-ras gene mutations in rare pancreatic and ampullary tumours.
abstract: OBJECTIVE
  Mutation of the K-ras oncogene is a frequent event in pancreatic ductal carcinogenesis and it is believed to occur at an early stage in the development of pancreatic cancer. However, little is known of the role of K-ras mutations in rare pancreatic epithelial neoplasms, endocrine tumours or other non-epithelial tumours of the pancreas. Furthermore, limited data are available regarding the role of K-ras mutations in the pathogenesis of ampullary tumours.
  
  
  METHODS
  Using single-strand conformation polymorphism (SSCP) and direct sequencing of polymerase chain reaction (PCR)-amplified fragments, we analysed codons 12 and 13 for the presence of oncogenic mutations of the K-ras oncogene. Tissues were obtained from patients undergoing tumour resection for various rare pancreatic or ampullary neoplasms (number of cases in brackets): ampullary adenoma (1), neuro-endocrine tumour (3), malignant fibrous histiocytoma of the pancreas (1), pancreatic cystadenocarcinoma (1), serous cystadenoma (1), and primary and metastatic adenocarcinoma of the ampulla (5) and pancreas (3).
  
  
  RESULTS
  K-ras gene mutations at codon 12 were detected in both pancreatic adenocarcinomas and in the metastatic lesion, whereas two ampullary cancers harboured a point mutation at codon 13: GGC-->GGG and GGC-->GGT. None of the other tumours exhibited a K-ras gene mutation at codons 12 or 13.
  
  
  CONCLUSIONS
  Pancreatic tumours other than ductal adenocarcinoma of the pancreas do not harbour mutations of the K-ras oncogene. In addition, ampullary adenocarcinomas may present with codon 13 mutations; however, these mutations were not associated with amino acid substitution. Therefore, K-ras gene mutations seem to be a specific genetic alteration contributing to the pathogenesis of pancreatic ductal adenocarcinoma.
authors.affiliation: Department of Gastroenterology, Otto-von-Guericke Universität Magdeburg, Germany.
authors.forename: M P
authors.initials: MP
authors.lastname: Ebert
authors.forename: J
authors.initials: J
authors.lastname: Hoffmann
authors.forename: R
authors.initials: R
authors.lastname: Schneider-Stock
authors.forename: H U
authors.initials: HU
authors.lastname: Kasper
authors.forename: H U
authors.initials: HU
authors.lastname: Schulz
authors.forename: H
authors.initials: H
authors.lastname: Lippert
authors.forename: A
authors.initials: A
authors.lastname: Roessner
authors.forename: P
authors.initials: P
authors.lastname: Malfertheiner
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics; D000368:Aged; D014670:Ampulla of Vater; D003062:Codon / Q000235:genetics; D003138:Common Bile Duct Neoplasms / Q000235:genetics*; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000235:genetics*; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational
chemical_list: D003062:Codon