Ha H et al revealed that soluble Programmed Death‐Ligand 1 (PD‐L1) was increased in progressive disease compared to baseline or at the time of the best response in biliary tract cancer.38Thaler FS et al reported changes in soluble transmembrane activator and CAML interactor (TACI) and soluble B‐cell maturation antigen (BCMA) according to the treatment response in primary central nervous system lymphoma.39 In pancreatic cancer, soluble biomarkers have not been well investigated; therefore, our study contributes to the literature by revealing the potential role of sTGF‐β. The gene discussed is TNFRSF17; the disease is biliary tract cancer.