Significance of tumor-associated macrophage density and CXCR4 expression in renal cell carcinoma

Objective Renal cancers are considered immunogenic tumors that are frequently infiltrated by immune cells. Tumor-associated macrophages (TAMs) represent a major leukocyte population, infiltrating tumors, and are associated with poor prognosis. Chemokines and their receptors play an important role in the tumorigenesis of many malignancies. The purpose of this investigation was to assess the immunohistochemical expression of TAM-related marker CD68 and chemokine receptor CXCR4 and study their correlation with other clinicopathological factors to detect the usefulness of these markers in the diagnosis and prognosis of renal cell carcinoma (RCC). Materials and methods Immunohistochemical expression of CD68 +ve TAM density and CXCR4 was analyzed in 57 cases of RCC and 10 cases of normal renal tissue. Results The higher expression of CD68 +ve TAMs was 57.8% and CXCR4 in 59.6% in RCC, which was statistically significantly different from the control group, which showed lower expression ( P <0.01 and <0.05, respectively). The expression of CD68 +ve tumor-associated macrophages was significantly related to high grade ( P <0.01), advanced stage ( P <0.05), and vascular invasion ( P <0.01). There was a significant correlation between CXCR4 overexpression in tumor cells and poor differentiation ( P <0.01), higher stage ( P <0.01), lymph node metastasis ( P <0.05), and vascular invasion ( P <0.01). A significant positive correlation between CD68 and CXCR4 in RCC was detected ( r =0.018, P <0.05). Conclusion Higher expression of CD68 +ve TAM density and CXCR4 may participate in the carcinogenesis, progression, and aggressiveness of RCC. Therefore, combined detection of these biomarkers could provide a prognostic role as well as novel therapeutic strategies, being new targets in the treatment of RCC.