High Expression of CCR7 Predicts Lymph Node Metastasis and Good Prognosis in Triple Negative Breast Cancer

Previous preclinical and clinical studies have reported a positive correlation between the expression of the C-C chemokine receptor 7 (CCR7) and the incidence of lymph node metastasis in breast cancer. However, the prognostic relevance of CCR7 expression in breast cancer remains contradictory till now. The aim of this study is to assess the correlation of the CCR7 expression with other clinicopathological features and prognosis in breast cancer.

The CCR7 gene amplification and mRNA expression levels from approximately 3,000 patients were retrieved from human breast cancer databases and analyzed. Furthermore, a total of 188 primary triple negative breast cancer patients were enrolled in this study (diagnosed since January 2009 to January 2013 from the Second Hospital of Dalian Medical University). The protein levels of CCR7 were examined by immunohistochemistry using paraffin-embedded tumor tissues.

The analysis of gene amplification and mRNA levels showed the expression of CCR7 in breast cancer correlated with better prognosis. When we compared the CCR7 expressions in different subtypes, the basal-like group showed the highest expression of CCR7 and exhibited a better prognosis. Consistently, Kaplan-Meier analysis of 188 triple negative breast cancer patients showed that the prognosis of patients with positive CCR7 expression was significantly better than those with negative expression (HR=0.642, p=0.0275). Additionally, we also observed a positive correlation between lymph node metastasis and the CCR7 expression (p=0.0096).

Our results indicated that elevated CCR7 expression as a marker for increased lymph node metastasis, in addition to serve as an independent prognostic indicator for better overall survival in triple negative breast cancer patients.