DPP4 and breast angiosarcoma: Considering the pivotal role of T cells in biliary atresia and the established functions of DPP4/CD26 in immune regulation and autoimmune diseases, we hypothesized that DPP4/CD26 contributes significantly to BA pathogenesis and may represent a promising immunotherapeutic target by modulating the dysregulated T cell responses characteristic of this condition, consistent with recently discussed immunotherapeutic approaches for pediatric liver diseases7,27.