Brush Cytology and K-ras Mutation Analysis of the Bile for the Diagnosis of Malignant and Benign Biliary Stricture Diseases

Park, Sang Hyun; Roe, Im Hwan; Lee, Myung In; Kim, Suk Bae; Huh, Jae Hyung; Tak, Woo Taik; Yu, Kwon; Kim, Jung Taik; Lee, Hak Sung; Lee, Jong Hwa

Abstract

BACKGROUND/AIMS
In cases that clear distinction between benign and malignant stricture is difficult on the basis of endoscopic retrograde cholangiopancreatography (ERCP) findings, cytologic confirmation is usually needed. Recently, K-ras mutation analysis of the bile has been reported to improve the diagnosis of biliary stricture disease. We investigated the effects of brush cytology and K-ras mutation analysis of the bile for the diagnosis of biliary stricture disease. METHODS: Brush cytology for the strictured bile duct and K-ras analysis of the bile were performed for 24 cases of bile duct adenocarcinomas histologically proven and 15 cases of benign strictures diagnosed by histology or a minimal follow-up of 6 months. RESULTS: Brush cytology was positive in 66.7% of patients with bile duct cancer if 2 cases of atypia were considered as positive. The K-ras mutation was observed in 66.7% of patients with bile duct cancer and 6.7% of patients with benign strictures. The diagnostic results obtained from both analyses were not different significantly from that obtained from brush cytology or K-ras analysis alone. CONCLUSIONS: K-ras mutation can be easily detected in the bile juice and mutant ras is concerned in pathogenesis of bile duct carcinoma. K-ras mutation analysis of the bile might be helpful to differential diagnosis of biliary stricture diseases.