The aim of this WG is to identify risk-factor specific minimally invasive biomarkers that can help in the personalised early detection of BTC in at-risk groups of patients (PSC, liver cirrhosis, biliary tract stone disease). The Action will have a unique platform for key prospective studies in populations at risk. Samples from patients with BTC from biobanks (tumour tissue, serum/plasma, bile, urine, stools) will be used to perform analyses of different types of biomarkers (proteins, metabolites, ctDNA, RNAs, microbiome), including the use of “omics” technologies, in large number of samples.