Liquid biopsy in biliary tract cancers: early diagnosis, precision therapy, and prognostic evaluation.

Biliary tract cancers represent a heterogeneous group of malignancies, including gallbladder cancer, intrahepatic cholangiocarcinoma, perihilar cholangiocarcinoma, and distal cholangiocarcinoma. These cancers share several common characteristics, such as challenges in early diagnosis, aggressive biological behavior, limited treatment options, and a propensity for drug resistance, all of which contribute to a notably poor prognosis for patients. Therefore, discovering new tumor biomarkers is urgently needed for early diagnosis, personalized treatment, and the prediction and monitoring of treatment effectiveness. Given that biopsy procedures are invasive and that repeated biopsies can diminish patient compliance, the ongoing advancement of liquid biopsy technology-characterized by its non-invasiveness and accessibility-promises to usher in a new epoch in clinical oncology. Currently, liquid biopsy mainly focuses on detecting and analyzing circulating tumor cells, cell-free DNA, and extracellular vesicles. This review aims to summarize the latest research advancements and future clinical applications of liquid biopsy in the context of biliary tract cancers.