Cancer immunotherapies targeting the PD-1 signaling pathway

Immunotherapy has recently emerged as the fourth pillar of cancer treatment,joining surgery,radiation,and chemotherapy. while early immunotherapies focused on accelerating t-cell activity,current immune-checkpoint inhibitors take the brakes off the anti-tumor immune responses. successful clinical trials with pd-1 monoclonal antibodies and other immune-checkpoint inhibitors have opened new avenues in cancer immunology. however,the failure of a large subset of cancer patients to respond to these new immunotherapies has led to intensified research on combination therapies and predictive biomarkers. here we summarize the development of pd-1-blockade immunotherapy and current issues in its clinical use. © 2017 the author(s).