Jg. Lee et al., DIAGNOSTIC UTILITY OF K-RAS MUTATIONAL ANALYSIS ON BILE OBTAINED BY ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY, Gastrointestinal endoscopy, 42(4), 1995, pp. 317-320
Background: Because K-ras oncogene mutations are present in more than
90% of pancreaticobiliary tumors, we tested prospectively whether K-ra
s mutational analysis of bile samples obtained during ERCP was superio
r to conventional bile cytology for diagnosis of malignancy. Methods:
Bile samples from 20 patients undergoing ERCP for evaluation of jaundi
ce were examined by both cytologic study and the polymerase chain reac
tion for the presence of K-ras oncogene mutations. Results: Polymerase
chain reaction products were amplified from the bile of 8 of 12 patie
nts with malignancy and 3 of 8 with benign disease; K-ras oncogene mut
ations were present in 4 of 8 polymerase chain reaction products from
malignant samples but absent in all 3 from benign samples. No cytologi
c results were positive for malignancy. Conclusions: Bile obtained dur
ing ERCP can yield positive results in K-ras mutational analysis, even
when results of conventional bile cytology are negative. In this stud
y, K-ras mutational analysis had a sensitivity of 33% (4 of 12), a spe
cificity of 100%, and a positive predictive value of 100% for diagnosi
s of malignancy.