Expression of the chemokine receptor CXCR4 correlates with a favorable prognosis in patients with adenocarcinoma of the lung

The relation between CXCR4 expression and the clinicopathological characteristics of lung cancer and patient prognosis is not well understood and remains controversial. We therefore investigated the relationship between CXCR4 expression and prognosis in patients with adenocarcinoma of the lung. Methods: We used semi-quantitative real time reverse transcription polymerase chain reaction to assess expression of CXCR4 mRNA in tumor samples from 79 patients with adenocarcinoma of the lung. We then correlated CXCR4 mRNA levels with known clinicopathological factors. We also used immunohistochemical staining to determine the subcellular localization of expressed CXCR4. Results: Within samples of tumor tissue, the cytosol and nucleus of tumor cells stained positively for CXCR4. By contrast, cells from normal tissue were negative for CXCR4. The 5-year disease-free survival rate among patients expressing higher levels of CXCR4 mRNA was significantly better than among those expressing lower levels (P = 0.0003 by log-rank test). Multivariate Cox proportional hazard analyses revealed, male (Hazard ratio, 2.96; 95% CI, 1.22–7.56; P = 0.012), lymph node metastasis (Hazard ratio, 3.61; 95% CI, 1.06–13.4; P = 0.040), and CXCR4 (Hazard ratio, 0.36; 95% CI, 0.13–0.94; P = 0.037) to be independent factors affecting the 5-year disease-free survival rate. Conclusion: Higher levels of CXCR4 expression by tumor cells are an independent predictor of a better prognosis in patients with adenocarcinoma of the lung.