VTCN1 and neoplasm: Studies have shown that tumor cells directly bind T-cell surface receptors through expressing B7-H4 protein or secreting soluble B7-H4 (sB7-H4) to inhibit the proliferation of CD4+ T cells, block the T-cell division cycle, and inhibit the release of antitumor cytokines and CD8+ T-cell cytotoxic activity against tumor cells (15,16).