Diagnostic utility of K-ras mutational analysis on bile obtained by endoscopic retrograde cholangiopancreatography.
BACKGROUND
Because K-ras oncogene mutations are present in more than 90% of pancreaticobiliary tumors, we tested prospectively whether K-ras mutational analysis of bile samples obtained during ERCP was superior to conventional bile cytology for diagnosis of malignancy.


METHODS
Bile samples from 20 patients undergoing ERCP for evaluation of jaundice were examined by both cytologic study and the polymerase chain reaction for the presence of K-ras oncogene mutations.


RESULTS
Polymerase chain reaction products were amplified from the bile of 8 of 12 patients with malignancy and 3 of 8 with benign disease; K-ras oncogene mutations were present in 4 of 8 polymerase chain reaction products from malignant samples but absent in all 3 from benign samples. No cytologic results were positive for malignancy.


CONCLUSIONS
Bile obtained during ERCP can yield positive results in K-ras mutational analysis, even when results of conventional bile cytology are negative. In this study, K-ras mutational analysis had a sensitivity of 33% (4 of 12), a specificity of 100%, and a positive predictive value of 100% for diagnosis of malignancy.
Division of Gastroenterology and Pathology, Duke University Medical Center, Durham, North Carolina, USA.
J G
JG
Lee
J W
JW
Leung
P B
PB
Cotton
L J
LJ
Layfield
P J
PJ
Mannon
D001646:Bile; D001661:Biliary Tract Neoplasms / Q000175:diagnosis / Q000235:genetics; D002760:Cholangiopancreatography, Endoscopic Retrograde; D004252:DNA Mutational Analysis; D011905:Genes, ras / Q000235:genetics*; D009154:Mutation; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000235:genetics; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity