Expression of M2 Macrophages and Regulatory T Cells in Colorectal Cancer and Their Correlation with Lymph Node Metastasis
Abstract BackgroundColorectal cancer (CRC) is among the most common malignancies worldwide. M2 macrophages and regulatory T cells (Tregs) are immunosuppressive cells that can promote tumor progression via inhibiting anti-tumor immunities. However, the significance and correlation of the two types of cells in colorectal cancer are still inconclusive. The purpose of this study is to detect the number of M2 macrophages and Tregs in colorectal cancer and lymph nodes and to explore the clinical and pathological significance of their existence.MethodsThe pathologic specimens and clinical data of 197 patients with Colorectal cancer after radical resection were collected. Immunohistochemical methods were used to detect the expression of M2 macrophages and Tregs in colorectal cancer tissues, adjacent tissues, and lymph node tissues in each group.ResultsCompared with adjacent tissues and non-metastatic lymph node tissues, M2 macrophages and Tregs not only increased significantly in cancer tissues and metastatic lymph node tissues (P < 0.001), but also M2 macrophages in non-metastatic lymph node tissues adjacent to cancer tissues the number of phages expressed also increased significantly (P < 0.05). In addition, there was a positive correlation between the number of cancer tissues and lymph nodes (P < 0.001).ConclusionM2 macrophages are involved in the formation of lymph node immunosuppressive environment and promote the development of CRC and lymph node metastasis together with Tregs. Upregulation of M2 macrophages and Tregs expression is a prognostic marker for monitoring the condition of colorectal cancer and judging the prognosis.