1.3　Progress of Tumor Immunotherapy

Currently, two major revolutions in tumor research and treatment are fulfilling the need for targeted treatments.One of these trends is based on significant advancement in cancer immunotherapy,allowing new treatments that enhance the body’s antitumor immunity functions.Because this approach is so promising, “cancer immunotherapy” was named “Breakthrough of the Year” by Science in 2013.During the last decade, a rapid understanding of the mechanisms that most tumor cells use to hide from the immune system has led to the improvement of new immunotherapeutic approaches against tumor.Overall, there are four different immunotherapeutic strategies.These include immune checkpoint blockade, cytokine therapy, cellular therapy and therapeutic vaccines.To understand how immune checkpoint blockade works, it is critical to comprehend the constant interaction between tumor and immune cells in the continuous process of cancer development.Tumor cells exploit various immune-regulatory mechanisms to achieve immune escape, thus suppressing immune responses against them within the tumor microenvironment.This is more obvious as the disease progresses.Several immune-related cells work towards the establishment of an immunosuppressive microenvironment, including regulatory T cells (Tregs), dendritic cells(DCs), myeloid-derived suppressor cells (MDSCs) and regulatory B cells.Therefore, within the tumor microenvironment, cancer cells along with immune cells excrete inhibitory cytokines and express checkpoint inhibitors that dampen the anti-tumor activity of specific T cells.During the last decade, a rapid understanding of the mechanisms that most cancer cells use to hide from the immune system has led to the improvement of new, immunotherapeutic approaches against cancer.Especially, the use of anti-PD-1 or anti-PD-L1 monoclonal antibodies (mab) has yielded top-notch medical responses in several cancers [2].(https://www.daowen.com)