FAS and neoplasm: Our results showed that the expression level of FGL2 was positively correlated with the expression levels of PRF1, granzyme K (GZMK), GZMA, GZMH, GZMB, and GZMM. The third antitumor function of CD8+ T cells is to induce the apoptosis of tumor cells via Fas/Fas ligand (FasLG) interactions.