ObjectiveMutation of theK-rasoncogene 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 ofK-rasmutations in rare pancreatic epithelial neoplasms, endocrine tumours or other non-epithelial tumours of the pancreas. Furthermore, limited data are available regarding the role ofK-rasmutations in the pathogenesis of ampullary tumours.Design and methodsUsing 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 theK-rasoncogene. 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).ResultsK-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: GGCrarr;GGG and GGCrarr;GGT. None of the other tumours exhibited aK-rasgene mutation at codons 12 or 13.ConclusionPancreatic tumours other than ductal adenocarcinoma of the pancreas do not harbour mutations of theK-rasoncogene. In addition, ampullary adenocarcinomas may present with codon 13 mutations; however, these mutations were not associated with amino acid substitution. Therefore,K-rasgene mutations seem to be a specific genetic alteration contributing to the pathogenesis of pancreatic ductal adenocarcinoma.
展开▼
