CD8A and neoplasm: Studies focused on T-cell responses in PDAC have shown that the progression of pre-malignant IPMN lesions to invasive cancer are associated with a consistent modification of the immune landscape whereby cytotoxic tumor-suppressing CD8+ T-cells, Th1 cells, and NK cells are progressively supplanted by immunosuppressive and tumor-promoting Th2 cells and Treg cells during the invasive stage of pancreatic cancer (17, 79).