William B. Coley: His Hypothesis, His Toxin, and the Birth of Immunotherapy

In recent years, immunotherapy has been the focus of great interest to researchers, clinicians, and the general public. Traditionally cancer therapy has been thought to be limited to surgery, radiation therapy, or chemotherapy. Some clinicians have considered it the so-called fifth pillar of cancer therapy, following surgery, cytotoxic chemotherapy, radiation, and targeted therapy. However, the origins of immunotherapy in cancer treatment reach back at least into the nineteenth century. This article reviews the origins, development, and future of immunotherapy.