Advances in the understanding of cancer immunotherapy.

The principal role of the immune system is to prevent and eradicate pathogens and infections. The key characteristics or features of an effective immune response include specificity, trafficking, antigen spread and durability (memory). The immune system is recognised to have a critical role in controlling cancer through a dynamic relationship with tumour cells. Normally, at the early stages of tumour development, the immune system is capable of eliminating tumour cells or keeping tumour growth abated; however, tumour cells may evolve multiple pathways over time to evade immune control. Immunotherapy may be viewed as a treatment designed to boost or restore the ability of the immune system to fight cancer, infections and other diseases. Immunotherapy manifests differently from traditional cancer treatments, eliciting delayed response kinetics and thus may be more effective in patients with lower tumour burden, in whom disease progression may be less rapid, thereby allowing ample time for the immunotherapy to evolve. Because immunotherapies may have a different mechanism of action from traditional cytotoxic or targeted biological agents, immunotherapy techniques have the potential to combine synergistically with traditional therapies.