Cancer immunotherapy: Breakthrough or "deja vu, all over again"?

From the application of Coley's toxin in the early 1900s to the present clinical trials using immune checkpoint regulatory inhibitors, the history of cancer immunotherapy has consisted of extremely high levels of enthusiasm after anecdotal case reports of enormous success, followed by decreasing levels of enthusiasm as the results of controlled clinical trials are available. In this review, this pattern will be documented for the various immunotherapeutic approaches over the years. The sole exception being vaccination against cancer causing viruses, which have already prevented thousands of cancers. We can only hope that the present high level of enthusiasm for the use of immune stimulation by removal of blocks to cancer immunity will be more productive than the incremental improvements using previous immunotherapies.