Preferential accumulation of immune cells in the tumor periphery. Formalin fixed liver sections with CRC liver metastases were stained with anti-CD3, anti-FOXP3 and F4/80 monoclonal antibodies to detect the presence of T cells, regulatory T cells and macrophages respectively. Low magnification scale bar=250μm, high magnification scale bar=50μm. Quantification of each cell type revealed significant differences between the tumor center and the periphery. Data is expressed as mean value of positive cells/ mm2±SEM with n≥5 for each group. (*P=0.0001 for T cells and regulatory T cells and #P=0.021 for macrophages).