CD8A and pancreatic ductal adenocarcinoma: Indeed, decreased CD8+ T to Treg cells ratio is correlated with a poor prognosis, unfavorable treatment outcome and finally diminished survival of patients suffering from various types of cancers such as non-Hodgkin’s lymphoma (NHL) (49), ovarian cancer (50), lung cancer (51), glioblastoma (52), pancreatic ductal adenocarcinoma (53), breast (54), hepatocellular carcinoma (55), cervical cancer (56), head and neck cancer (57), gastric cancer (58), melanoma and other malignancies (59).