CD226 and central nervous system cancer: We found that BST2 was positively correlated with several immune checkpoint genes, including PD1, ICOS, CD80, CD226, CD86, HAVCR2, CD40, PDCD1LG2, CD48, and TNFRSF14. The expression of BST2 was positively correlated with the expression of M2 type macrophages in all grades of gliomas, but the amount of CD8+ T cells exhibited inconsistent results, which highlights the complexity of the microenvironment of gliomas.