Bile is a digestive fluid produced by the liver and stored in the gallbladder. It is released into the duodenum (small bowel) together with the pancreatic juices during meals.
Bile functions include:
There are patients that suffer from biliary strictures or stenoses, when the bile ducts get smaller or narrower, causing a buildup of bile. These stenoses may have diverse origin, and the discrimination between benign and malignant causes in their early stages is not satisfactorily resolved yet. Benign conditions include primary sclerosing cholangitis (PSC), chronic pancreatitis, choledocolithiasis, bile duct injury and infections, among others. Malignant stenoses are mostly attributable to biliary tree neoplasias such as cholangiocarcinoma (CCA), or to pancreatic cancers, like pancreatic ductal adenocarcinoma (PDAC). These patients undergo different medical interventions aiming to relief the stagnant bile while trying to obtain images or tissue samples for diagnosis. These interventions include a range of non-invasive imaging techniques plus endoscopic retrograde cholangiopancreatography (ERCP). So far, drained bile was not systematically collected for analyses.
The bile fluid is in direct contact with the cells of the bile duct system, including pre-malignant and malignant cells if present. Therefore, bile could be used as a liquid biopsy strategy to discriminate benign and malignant stenoses. Molecular analysis of bile could also serve to stratify patients for targeted cancer therapies.