For instance, CD4+ Th2 cells skew the immune response toward tumor promotion by suppressing CD8+ T cell activation and fostering tumor invasion and metastasis, as evidenced in breast and pancreatic cancer models (9).Similarly, Tregs exacerbate immunosuppression via inhibiting Th1 differentiation and CD8+ T cell effector functions, thereby dampening the host’s anti-tumor immune responses (10). This evidence concerns the gene CD8A and familial pancreatic carcinoma.