The Role of Tumor Microenvironment in Cancer Immunotherapy

Cancer pathogenesis in human is comprised by a series of complicated biological processes, whereby the rivalry between foreign tumor and inherent immunity determines the success or failure of this defense battle. As the "seed and soil" hypothesis implicated, tumor initiation and progression are not only driven by (epi) genetic abnormalities, but also influenced by surrounding tumor microenvironment, which adds another layer of understanding to cancer biology. More importantly, growing microenvironment-related studies provide the theoretical reasons for developing more effective cancer immunotherapy in clinical practice. In this review, we will present an overview of tumor microenvironmental components involving immune tolerance, as well as selective research advances in cancer immunotherapy.