PDCD1 and central nervous system cancer: The highest expression was detected in the WHO glioma grade IV tumors (CD274 p = 2.0e − 08, HAVCR2 p = 1.5e − 09, LAG3 p = 9.7e − 05, PDCD1 p = 5.6e − 05, PDCD1LG2 p = 2.2e − 18, and SIGLEC15 p = 4.3e − 05) (Figure 2).