Transcriptional regulation of the immune checkpoints PD-1 and CTLA-4

Immunotherapy targeting immune checkpoints(ICs)has revolutionized the field of cancer treatment.ICs are a group of proteins that provide stimulatory or inhibitory signals to regulate T-cell activation,tolerance,and exhaustion.To date,some immune checkpoint inhibitors(ICIs)targeting TIM-3,LAG-3,TIGIT,and VISTA are under investigation for their clinical applications.However,only ICIs against CTLA-4,PD-1,and PD-L1 are approved by the FDA and widely used as first-line or second-line treatments for multiple cancer types.CTLA-4 and PD-1 are coinhibitory receptors that are mainly expressed by T cells.