Overexpression of CCR7 mRNA in nonsmall cell lung cancer: correlation with lymph node metastasis

Tumor cell migration into the lymph nodes is an important aspect of cancer, yet little is known about the processes involved. CCR7 has been shown to play an important role in tumor cell migration and lymph node metastasis. The aim of our study was to evaluate the expression of CCR7 in nonsmall cell lung cancers (NSCLCs). We investigated CCR7 expression in 71 patients with NSCLC who underwent curative tumor resection by means of reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. CCR7 mRNA was expressed in 45 cases (63.3%). The CCR7 mRNA expression was significantly associated with lymph node metastasis, stage, lymphatic invasion, CCR7 protein and CXCR4 protein (p = 0.0001 for lymph node metastasis; p < 0.0001 for stage; p = 0.0454 for lymphatic invasion; p < 0.0001 for CCR7 protein; p = 0.0013 for CXCR4 protein). Twenty-six (57.8%) of 45 cases with CCR7 mRNA expression in their cancer tissues were node-positive, whereas only 3 (11.5%) of 26 cases without CCR7 mRNA expression were node-positive. Furthermore, expression of CCR7 mRNA was shown to be an independent predictor of lymph node metastasis by multivariate analysis (p = 0.0117). Our study demonstrates that CCR7 might be related to the development of lymph node metastasis in NSCLC. The expression of CCR7 mRNA could open up a new window for the diagnostic staging and treatment of NSCLC.