Abstract
Detection of the K-ras mutation at codon 12 in pancreatic juice is a valuable diagnostic modality for differentiating chronic pancreatitis from pancreatic carcinoma. We attempted to detect K-ras mutations in bile DNA, collected from PTCD tubes, as a diagnostic approach to biliary obstruction. Since bile salt acts as a detergent in removing components from the plasma membrane, we first examined the degeneration of cells according to bile exposure time using cell line NOZ. High molecular weight DNA could not be extracted from cells exposed to bile for 12 or more hours. Moreover, NOZ-DNA exposed to bile for 24 or more hours could not be amplified by the PCR method. Therefore, in order to detect mutations in bile, it is necessary to use fresh materials and to use a highly sensitive method, because of the considerable cell contamination present. We next examined cytology and the K-ras mutation in 13 samples using the enriched PCR method. The K-ras mutation was detectable in the bile of all pancreastic carcinoma cases which had been clinically and radiologically diagnosed, but of which cytology was not confirmative. These results suggest that the detection of K-ras mutations in PTCD tube bile may be a useful diagnostic approach to the detection of biliary tract obstruction.
