Detection of point mutations in K-ras gene at codon 12 in bile from percutaneous transhepatic choledochal drainage tubes for diagnosis of biliary strictures

Int J Pancreatol. 1995 Dec;18(3):215-20. doi: 10.1007/BF02784944.

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.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Base Sequence
  • Bile / chemistry
  • Cholestasis / diagnosis*
  • Codon
  • Drainage
  • Female
  • Gene Amplification
  • Genes, ras*
  • Humans
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Pancreatic Neoplasms / diagnosis*
  • Point Mutation*
  • Tumor Cells, Cultured

Substances

  • Codon