The Prognostic Significance of FoxP3+ T Cells and CD8+ T Cells in Colorectal Carcinomas.

Recent studies report that tumor microenvironment effects prognosis of colorectal cancers. We analyzed the densities of FoxP3+ cells and CD8+ cells, the ratio of FoxP3+/CD8+ cells and the relationship between these parameters, clinicopathological features, and prognosis. A total of 186 colorectal adenocarcinoma were evaluated in terms of clinicopathological features. Immunohistochemically, densities of intratumoral (IT; IT-FoxP3) and nontumoral (NT; NT-FoxP3) FoxP3+ cells and IT-CD8 and NT-CD8 CD8+ cells were calculated. The ratio of Foxp3/CD8 was recorded. IT-FoxP3 and the ratio of IT-FoxP3/IT-CD8 were higher than NT-FoxP3 and the ratio of NT-FoxP3/NT-CD8, respectively. In multivariate analysis, high FoxP3+ cell density is the most important predictive marker after clinical stage and surgical margin positivity in disease-free survival and the most important predictive marker after clinical stage in overall survival (OS). Short OS time was correlated with clinical stage, decrease in IT-FoxP3, increasing age, number of metastatic lymph nodes, surgical margin positivity, satellite tumor nodule, medullary carcinoma, and the number of pericolorectal lymph nodes. The ratio of FoxP3/CD8 increased noticeably in the IT area, but no relationship was found with survival. The relationships of the cells with one another in the tumor microenvironment seem to have many secrets. Studies in large series supported by molecular techniques can illuminate those secrets to some extent.