VTCN1

V-set domain containing T-cell activation inhibitor 1 (VTCN1), also known as B7X, B7H4, B7S1, B7-H4, B7h.5, VCTN1, PRO1291, is a protein that belongs to the B7 costimulatory protein family. It is widely expressed in kidney, liver, lung, ovary, placenta, spleen and testis. VTCN1 proteins are present on the surface of antigen-presenting cells and interact with ligand bound to receptors on the surface of T cells. By inhibiting T-cell activation, proliferation, cytokine production and development of cytotoxicity, VTCN1 can negatively regulate T-cell-mediated immune response. When expressed on the cell surface of tumor macrophages, VTCN1 plays an important role, together with regulatory T-cells (Treg), in the suppression of tumor-associated antigen-specific T-cell immunity. This protein is also found to be involved in promoting epithelial cell transformation.
Moreover, various studies demonstrate that VTCN1 protein is overexpressed in breast, ovarian, endometrial, renal cell (RCC) and non-small-cell lung cancers (NSCLC), which make it become a hot target for specific immune therapy strategies, such as antibody-drug conjugate (ADC).

Gene ID: 79679
UniProt ID: Q7Z7D3