High expression of CD8 predicts favorable prognosis in patients with lung adenocarcinoma

Lung carcinoma is the most common cause of malignant death worldwide. CD8 T cells, as critical elements in antitumor immunity, could function as good prognostic indicators in various kinds of cancers such as renal cell carcinoma and colorectal cancer, but its prognostic role in lung adenocarcinoma is still unclear. The objective of this study was to explore the prognostic role of CD8 expression in lung adenocarcinoma.Paired tumor and adjacent noncancerous tissues were obtained from 102 patients with lung adenocarcinoma, and CD8 expression of these samples was examined by immunohistochemistry. We evaluated the relationships between the expression of CD8 and pathological grade, TNM stage, clinical stage, as well as overall survival (OS).Expression of CD8 was significantly increased in lung adenocarcinoma compared with that in adjacent lung adenocarcinoma (P < .001). CD8 expression was negatively correlated with pathological grade (r = -0.216, P = .022) and N stage (r = -0.372, P < .001), while no statistical correlation with T stage, or clinical stage. Importantly, OS was numerically increased in patients with high expression of CD8 than the group of intermediate and low CD8 expression (P = .12). Furthermore, CD8 could significantly increase OS (P = .043, HR: .713, 95%CI: .515-.989) by univariate Cox's proportional hazards regression analysis.Our data indicated that expression of CD8, as a protective factor, is correlated with the outcome of patients with lung adenocarcinoma. Furthermore, CD8 might be a novel prognostic biological marker for patients with lung adenocarcinoma.