Immunoflourecent Staining Detect the Prognostic significance of M2 macrophage

Abstract

     Tumor cells use multiple mechanisms to invade extracellular matrix and metastasize to distant organs. The interaction between the tumor cells and stromal cells in the tumor microenvironment plays an important role in tumor growth and metastasis. Tumor associated macrophage (TAM) are prominent stromal cells in this interaction. They secret a variety of growth factors, cytokines, chemokines, and enzymes that regulate tumor growth, angiogenesis, invasion, and metastasis. Macrophages show two polarization states in response to different micro-environmental signals. M1macrophages are pro-inflammatory and function as bactericidal and antigen-presenting cells. M2 macrophages have an immunosuppressive phenotype. Thus the aim of current study is to find out whether there is prognostic value  for M2 macrophage that infiltrating colorectal tumor tissue through linking its expression level with tumor histopathological variables by using immunoflourecent technique. Further more to find if there an association for M2 macrophage with tumor cell proliferation by using Ki67 as a proliferation marker. Current study found that the Mean Ki67 score was significantly higher in patients than in control group, (P<0.001), moreover the common macrophage mean CD68⁺ macrophages, and M2 macrophage (CD163⁺) count was significantly higher in patients than in control group  (P<0.001, P<0.001), respectively. I addition present study demonstrated that the M2 macrophage (CD163⁺) count showed significant correlation with tumor grade (P<0.001), LN involvement (P<0.001), stage (P<0.001), and Ki67% (P<0.001).  However, when the ratio of CD68/CD163was considered, the following results were obtained: there was no significant correlation between CD68/CD163 ratio and both of tumor stage and LN involvement (P>0.219, P>0.468 respectively). While there was significant correlation between CD68/CD163 ratio and tumor grade (p<0.03). From above results one can conclude that high expression of CD163 macrophages is associated with poor prognosis and from other hand could be targeted by immune therapy to lower the progression of colorectal cancer.