title: Detection of point mutations in K-ras gene at codon 12 in bile from percutaneous transhepatic choledochal drainage tubes for diagnosis of biliary strictures.
abstract: Detection of K-ras mutations at codon 12 constitutes one modality for diagnosis of pancreatic tumors. We attempted to detect K-ras mutations in DNA from bile collected through percutaneous transhepatic choledochal drainage (PTCD) tubes as a diagnostic approach to biliary strictures. Since bile salts induce cell damage, we first investigated the degeneration of cells according to bile exposure time using cell lines. High-mol-wt DNA could be extracted from cells exposed to bile for 6 h, but not from those exposed for 12 h. However, DNA exposed to bile for up 12 h could be amplified by the polymerase chain reaction (PCR) method. Therefore, K-ras mutations in fresh bile specimens collected from 15 patients through PTCD tubes were examined using PCR with restriction enzyme digestion. K-ras mutations were found in five out of five (100%) pancreatic cancers, all of which were negative according to cytodiagnosis of the same bile. On the other hand, K-ras mutations were not detected in bile from biliary tract cancers or metastatic neoplasms, except for one bile duct carcinoma and one metastatic case. Thus, although K-ras mutation alone is not an absolute marker for cancer, detection of K-ras mutations in fresh bile from PTCD tubes is a useful adjunct for diagnosis of pancreatic carcinomas in cases of biliary tract strictures.
authors.affiliation: First Department of Surgery, Kobe University School of Medicine, Kobe, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ajiki
authors.forename: H
authors.initials: H
authors.lastname: Onoyama
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Fujimori
authors.forename: S
authors.initials: S
authors.lastname: Maeda
authors.forename: Y
authors.initials: Y
authors.lastname: Saitoh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D001646:Bile / Q000737:chemistry; D002779:Cholestasis / Q000175:diagnosis*; D003062:Codon; D004322:Drainage; D005260:Female; D005784:Gene Amplification; D011905:Genes, ras; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010190:Pancreatic Neoplasms / Q000175:diagnosis*; D017354:Point Mutation; D014407:Tumor Cells, Cultured
chemical_list: D003062:Codon