Identification and validation of specific methylation profile in bile for differential diagnosis of malignant biliary stricture

Objective: This study was aimed to identify the specific methylation profile in bile specimens of pancreaticobillary diseases for differential diagnosis of malignant biliary stricture. Design and methods: In a total of 80 bile specimens from pancreaticobillary diseases, the methylation status of 19 tumor suppressor genes were analyzed by methylation-specific PCR and the methylation index (MI) were compared between the malignant and benign groups. Results: Methylation of DKK3, p16, SFRP2, DKK2, NPTX2 and ppENK were more frequently detected in the bile of malignant biliary strictures than benign patients. When setting MI 0.5 as the threshold, this 6-gene panel could distinguish the malignant biliary stricture with a high sensitivity, specificity and accuracy (77.27%, 77.78% and 77.50%, respectively). Conclusion: The methylation profile including 6 specific genes in bile may be a promising biomarker for differential diagnosis between malignant and benign biliary strictures. (C) 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.