PDCD1 and cancer: Besides, we investigated immune checkpoint proteins, including CD274, CTLA4, HAVCR2, LAG3, PDCD1, PDCD1LG2, and TIGIT, which put the brakes on immune cell functions to regulate immune activation, but the activity of immune checkpoint proteins is exploited in tumors to evade immune surveillance and attack.[171] The results showed that CD274, HAVCR2, PDCD1LG2, and SIGLEC15 are positively related to GSPT1, while LAG3 and PDCD are negatively associated with GSPT1 in most cancers.