PRF1 and neoplasm: As shown in Figures 5B,C, low concentration of IL-24 did not affect either perforin or granzyme B expression in CD8+ T cells (Tukey tests, P > 0.05), while high concentration of IL-24 promoted perforin and granzyme B expression in both peripheral and tumor-infiltrating CD8+ T cells (Tukey tests, P < 0.05).