USEFULNESS OF K-RAS GENE MUTATION AT CODON-12 IN BILE FOR DIAGNOSING BILIARY STRICTURES

Point mutations of the K-ras gene at codon 12 are often detected in th e pancreatic juice of patients with pancreatic cancer. Detection of th ese mutations may, thus, have diagnostic implications. K-ras mutations may also have diagnostic potential for other biliary tumors. We sough t to detect K-ras mutations in DNA obtained from bile in patients with biliary tract cancers, pancreatic cancer and benign biliary disease b ut who had obstructive jaundice. In 35 patients, bile was collected du ring percutaneous transhepatic choledocal drainage (PTCD) catheters. K -ras gene mutations at codon 12 in the samples were examined using mut ant-allele-specific-amplification (MASA). We compared these results wi th cytological analyses of bile. K-ras mutations at codon 12 in bile w ere detected in 11 of 14 (79%) of the patients with biliary duct cance r, 3 of 9 (33%) with pancreatic cancer but not in patients with gallbl adder cancer (n=3), papilla of Vater's cancer (n=3) or benign biliary diseases (n=6). In the patients, where cytological evaluation did not reveal malignant cells, K-ras mutations in bile were detected in 5 of 7 (71%) patients with biliary duct cancer and 2 of 5 (40%) with pancre atic cancer. This approach, when used in conjunction with bile cytolog y, may improve the yield in diagnosing suspected malignant tumors of t he pancreatic-biliary system.