Interestingly, the expression levels of five key CTL effector genes, Fasl, prf1, Gzma, Gzmb and Ifng, and the immune suppressive gene Il10, were significantly down-regulated in the IFNAR1-KO tumor-infiltrating CTLs from both MCA and MC38 tumor, respectively, as compared to the WT tumor-infiltrating CTLs (Fig. 5A). Here, PRF1 is linked to neoplasm.