The prognostic impact of anti-cancer immune response: a novel classification of cancer patients

Abstract

Until now, the anatomic extent of tumor (TNM classification) has been, by far, the most important factor to predict the prognosis of colorectal cancer patients. However, in recent years, data collected from large cohorts of human cancers demonstrated that the immune contexture of the primary tumors is an essential prognostic factor for patients' disease-free and overall survival. Global analysis of tumor microenvironment showed that the nature, the functional orientation, the density, and the location of adaptive immune cells within distinct tumor regions influence the risk of relapse events. An immune classification of the patients was proposed based on the density and the immune cell location within the tumor. The immune classification has a prognostic value that is superior to the TNM classification, and tumor invasion is statistically dependent on the host immune reaction. Tumor and immunological markers predicted by systems biology methods are involved in the shaping of an efficient immune reaction and can serve as targets for novel therapeutic approaches. Thus, the strength of the immune reaction could advance our understanding of cancer evolution and have important consequences in clinical practice.

Fig. 1

General scheme of immune control of metastatic spread and clinical outcome. Four major groups of patients were found according to immune status and relapse. Optimal immune response is characterized by high-immune T cell infiltration, immune coordination, low VEGF expression, and low Th17 density. Altered immune reaction is either, (1) high-immune T cell infiltration and absence of immune coordination or increased VEGF expression, (2) heterogeneous-immune T cell infiltration between CT and IM regions, and high or heterogeneous Th17 densities, and (3) low-immune T cell infiltration and absence of immune coordination