B7-H4 in Cancer Immune Evasion and Immunotherapy.

B7-H4 (also known as B7x or B7S1) is a member of the B7 family and is expressed in a broad spectrum of malignancies, with particularly elevated levels in tumors arising from female reproductive organs. Functionally, B7-H4 suppresses T-cell activation and effector responses, thereby facilitating immune evasion within the tumor microenvironment. In this review, we highlight recent advances in the biology of tumor-associated B7-H4, including its tissue distribution, subcellular localization, regulatory mechanisms of expression, and emerging therapeutic strategies targeting B7-H4 for cancer treatment.