PRF1 and neoplasm: TNF-α (Figures 4A,B), granzyme B (Figures 4C,D), and perforin (Figures 4E,F) were all downregulated in cells lacking JAK1; this was rescued by the re-expression of codon-optimized JAK1 (Figure 4), implying that JAK1 deficiency prevents killing by tumor-specific T-cells.