The Frequency of Tumor-infiltrating Tie–2-expressing Monocytes in Renal Cell Carcinoma: Its Relationship to Angiogenesis and Progression

Objective To examine the frequency of tumor-infiltrating Tie–2-expressing monocytes (TEMs) in renal cell carcinoma (RCC) and its association with microvessel density (MVD) and other clinical-pathologic features. Materials and Methods This study enrolled 65 consecutive patients with RCC treated with radical nephrectomy. The frequency of tumor-infiltrating TEMs, which was defined as CD14+ Tie-2+ cells, was assessed using flow cytometry. MVD was measured by immunohistochemistry using anti-CD34 antibody. The association between clinicopathologic parameters, MVD, and the frequency of tumor-infiltrating TEMs in RCC was assessed. Results High frequency of tumor-infiltrating TEMs was significantly associated with advanced stage ( P = .018), positive lymph nodes ( P = .013), high grade ( P = .019), and metastases ( P = .006). Correlation analysis revealed that the frequency of TEMs was positively correlated with MVD. Conclusion Our findings revealed a significant association between prognostic tumor features, MVD, and the frequency of tumor-infiltrating TEMs in RCC and indicated that TEMs may play an important role in angiogenesis and progression of RCC.