K-ras point mutations in the supernatants of pancreatic juice and bile arereliable for diagnosis of pancreas and biliary tract carcinomas complementary to cytologic examination

In order to clarify whether DNA analysis for EC-ras mutation can be used to diagnose cancers in supernatants of pancreatic juice and bile, samples fro m 29 cases of pancreatic, biliary tract, gastric, and neuroendocrine carcin omas, I malignant lymphoma case, 2 cases of pancreatic adenoma, 9 cases of chronic pancreatitis and 21 other non-cancer cases were examined, Polymeras e chain reaction (PCR) products for Ii-ras gene codons 2 to 97 of exons 1 a nd 2 were generated with 33/33 (100%) pancreatic juice and 41/41 (100%) bil e samples. By the single strand conformation polymorphism (SSCP) method, po int mutations were detected in the pancreatic juice or bile supernatants of 13/13 (100%) pancreas cancer cases, 5/14 (35.7%) biliary tract cancer case s, 1/2 (50.0%) pancreatic adenoma cases and 3/9 (33.3%) chronic pancreatiti s cases. Direct sequencing confirmed identical point mutations in the super natants, malignant cells of cytologic smears of pancreatic juice or bile an d cancer tissues. The DNA analysis demonstrated the presence of K-ras point mutations in 3 cases of pancreatic carcinomas with false-negative cytologi c diagnoses. This novel method allows simultaneous testing for genetic abno rmalities in supernatants of pancreatic juice and bile, after removing cell s for cytologic diagnosis and screening for pancreatic and biliary tract tu mors.