CD4 and hepatobiliary neoplasm: A study on hepatobiliary tumors treated with hypofractionated proton therapy (HPT) radioactivity has suggested that overall survival (OS) is significantly related to CD4+ CD25+ T cell and CD4+ CD127+ T cell fractions in intrahepatic ICC, which reveals that CD4+ T cell and its related cytokines may be vital factors for the prognosis of CCA 52.