Immunotherapy in Breast Cancer- Paving New Roads?

Significant advances have been made in our understanding of the mechanisms of innate and adaptive immunity and the mechanisms by which tumors escape from the normal process of immune surveillance. However, effectively harnessing the power of the immune system to specifically target the tumor cells has proven quite difficult, in large part due to the fact that tumors are composed of patient’s own cells, expressing antigens recognized as “self” and thus escaping the immune surveillance. For breast cancer treatment, the first successful inroads in immunotherapy came with the introduction of monoclonal antibodies against a membrane receptor for the epidermal growth factor receptor family (HER2). In 1998 the first monoclonal antibody against the Her 2 antigen was approved for clinical use (trastuzumab). Clinical trials combining trastuzumab with various chemotherapy regimens have consistently shown improvement in survival in both metastatic as well as early stage breast cancer. Another promising approach has been the development of anti HER 2 vaccines. More recently the discovery of immune modulating antibodies (checkpoint inhibitors) and their success in the treatment of cancers such as melanoma and renal cell carcinoma has lead to renewed interest in immune therapies in cancer in general and new clinical trials exploring the role of immune therapies in breast cancer.