Macrophage level is not affected by monocyte chemotactic protein-1 in invasive ductal breast carcinoma

Purpose and method: Monocyte chemotactic protein-1 (MCP-1) is a chemokine involved in the macrophage infiltration of tumor tissue. Tumor-associated macrophages (TAMs) are a population of mononuclear phagocytic cells that can have a complex function in tumor biology. The aim of this study was to determine the possible correlation between parenchymal MCP-1 expression and TAM level by immunohistochemical analysis of 97 invasive ductal breast carcinomas, not otherwise specified (NOS), and to investigate their relation with tumor size, histological grade, mitotic activity index (MAI) and lymph node status. Secondly, the MCP-1 mRNA was determined by reverse transcriptase–polymerase chain reaction (RT-PCR) in eight samples of normal breast tissue and 27 samples of invasive breast carcinomas and compared with TAMs. Results: MCP-1 immunoreactivity was present in tumor cells (17/97), but also in TAMs, fibroblasts and endothelial cells. The statistical analysis did not show a significant correlation between MCP-1 expression in tumoral epithelium and tumor size, histological grade, MAI, lymph node status or TAMs. The results of RT-PCR showed that, in all cases of breast carcinomas (27/27) and the majority of normal breast tissues (7/8), the number of detected MCP-1 cDNA copies was above the detection limit. However, carcinomas showed higher levels of MCP-1 mRNA than normal breast tissue. Nevertheless, the statistical analysis did not find a significant correlation between MCP-1 expression and macrophage infiltrations. Conclusion: These results indicate that MCP-1 is probably not the only and/or crucial factor involved in macrophage attraction to tumor locus in breast carcinoma.