High-level C-X-C chemokine receptor type 4 expression correlates with brain-specific metastasis following complete resection of non-small cell lung cancer

Brain-specific metastasis is one of the primary causes of recurrence following complete resection of non-small cell lung cancer (NSCLC) and the underlying mechanism remains unclear. The present study was designed to investigate the correlation between C-X-C chemokine receptor type 4 (CXCR4) expression and brain-specific metastasis of NSCLC. Lung cancer tissues from 105 patients who underwent complete tumor resection between January 1998 and June 2008 (sample group, 34 with brain metastasis during the follow-up period; control group 1, 34 without metastasis during the follow-up period; and control group 2, 37 with other organ metastasis, excluding brain metastasis, during the follow-up period) were examined by immunohistochemistry to detect the expression of CXCR4 protein. The differences in CXCR4 expression were compared using McNemar's χ2 test. Estimation of survival was calculated with the Kaplan-Meier method and the statistical differences were analyzed with the log-rank test. Overexpression of CXCR4 protein was observed in 31 (91.2%) NSCLC patients with brain metastasis, which was greater than that observed in the NSCLC patients with other organ metastases (73.0%; P=0.048) and without metastases (14.7%; P