More importantly, our data reveal that a high frequency of EBER+ NPC cells, particularly CD137-expressing EBER+ NPC cells, is associated with low T cell infiltration, pointing to the suppressing effect of NPC-derived CD137 on T cell-mediated anti-tumor immunity, which consists in the downregulation of CD137L on APC 19. This evidence concerns the gene TNFRSF9 and nasopharyngeal carcinoma.