Immune Therapy

In the 1850s, doctors in Germany noticed that patients' tumours would occasionally shrink if their tumour became infected. This observation led to the idea that the body's immune system could be harnessed and made to fight cancer.
Around the same time, doctors throughout Europe, encouraged by the success of Edward Jenner's smallpox vaccine, attempted to make a 'cancer vaccine' by injecting patients with crude extracts of tumours from other cancer patients. These treatments were largely ineffective, but the field of 'immunotherapy' was born.

read more at http://info.cancerresearchuk.org/cancerandresearch/learnaboutcancer/treatment/immunotherapy/?a=5441