Advances in Research on Immune Checkpoint TIGIT in Tumors

T-cell immunoglobulin and immune receptor tyrosine inhibitory motif domain protein (TIGIT) is a newly discovered immune checkpoint in recent years. As a receptor of immunoglobulin superfamily, TIGIT participates in immune suppression and causes tumor immune escape by inhibiting immune cell function. The application of TIGIT antibodies for the treatment of malignant tumors has shown promising future in tumor immunotherapy. Domestic and foreign pharmaceutical enterprises have developed a series of drugs targeting TIGIT, including TIGIT monoclonal antibodies and programmed death receptor-1 (PD-1)/TIGIT bispecific antibodies. At present, there are more than 10 TIGIT antibodies in the world that have entered the clinical studies, but no related drugs have been approved for marketing. This article introduces the expression, molecular structure and signaling pathway of TIGIT, as well as its immune regulatory mechanisms and the progress in research and development of related new drugs.