One of the roles of the immune system is in part to recognize self and “foreign” proteins. In the case of cancer, this implies recognition and elimination of cancer cells by the body. There many challenges in developing effective immunotherapies including tolerance of the cancer cells to the therapy and destruction of the therapy by the immune system.
Cancer cells have may ways to avoid the immune system. They can recruit myeloid-derived suppressor cells (MDSCs) into the tumor environment. The MDSCs suppress the local immune response to the cancer and promote invasion and metastasis via a variety of mechanisms. Tumors can also increase numbers of Treg cells and this is often associated with a poor prognosis. Cancer can produce many different kinds of cytokines which are proteins which can affect the growth/activity of immune system and blood cells.
There are several examples of immunotherapies including:
Cancer vaccines are the ultimate goal of immunotherapy. These vaccines can take weeks to months to result in a clinical response as opposed to more traditional therapies like chemotherapy or radiation. There is only one cancer vaccine in veterinary medicine which is called Oncept. Oncept is a vaccine that stimulates the [canine] immune system to produce a response and antibodies against tyrosinase. Tyrosinase is a protein in the body used in the synthesis of melanin and is present in many melanoma cancers.