The CC chemokine receptor 9 (CCR9) plays an important role in tumorigenesis and metastasis in various cancers. Our previous studies have shown the aberrant expression of CCR9 in non-small cell lung cancer (NSCLC) cell lines, revealing that the CCR9-CCL25 axis modulates cell migration and invasion, and supports cancer cell survival by inhibiting apoptosis in vitro and in vivo. In the present study, we aimed to evaluate the expression and possible prognostic role of CCR9 in lung adenocarcinoma.

Immunohistochemical analysis of CCR9 expression was performed on 144 lung adenocarcinoma tissues and 30 adjacent normal lung parenchymal tissues. We assessed the correlation of CCR9 expression with clinicopathological characteristics and the prognosis of lung adenocarcinoma.

The expression of CCR9 was increased in lung adenocarcinoma tissue compared with normal lung tissue. Moreover, such an expression was positively correlated with tumor size (p = 0.032), lymph node metastasis (p = 0.002) and advanced TNM stage (p = 0.012). In addition, the patients with negative CCR9 expression exhibited a higher overall survival (OS) compared with those with positive CCR9 expression. Multivariate analysis showed that the CCR9 expression was an independent prognostic factor for the OS of patients with lung adenocarcinoma.

We, for the first time, reported that CCR9 could be beneficial in predicting lymph node metastasis, and it might act as a novel prognostic biomarker for lung adenocarcinoma.