Additionally, there are currently three ongoing clinical trials using a Dkk1-neutralizing monoclonal antibody (DKN-01, Leap therapeutics) for advanced biliary tract cancer (NCT04057365), prostate cancer (NCT03837353), and locally advanced or metastatic gastric or gastroesophageal junction adenocarcinoma (NCT04363801). This evidence concerns the gene DKK1 and biliary tract neoplasm.