What is Cancer Immunotherapy?
The advent of precision medicine has ushered in a new way of battling cancer. With an understanding of the genetics of cancer, treatment is now personalized specific to a patient's unique tumor characteristics. However, one of the limitations of precision medicine is the inevitable development of treatment resistance by the tumor. The vast majority of patients, after experiencing clinical benefit, will require a change in treatment as their tumor mutates. As a cancer changes, so must our response. In this perennial "cat and mouse" game, new approaches must be developed to keep up.
Instead of always playing "catch up" with a tumor, immunotherapy offers the greatest hope in our search for a cancer cure. By harnessing the power of the immune system, the body can keep up with new mutations. What is cancer immunotherapy?
Immunotherapy can be broken into 3 major categories: monoclonal antibodies, vaccines and nonspecific immunotherapies. Antibodies are the body’s ammunition against cancer. In the lab, antibodies can be produced specific to a patient’s tumor. These are then injected into a patient.
Vaccines are also a promising area of research. Already we have effective vaccines against some cancers. There are vaccines for HPV, which protects against cervical cancer, and hepatitis B, which protects against liver cancer. Vaccines are also being developed to treat cancer. Recently an effective vaccine against metastatic prostate cancer was approved (Provenge).
Finally, nonspecific immunotherapies are one of the hottest areas in cancer research currently. These can be divided into:
Cytokines – These are molecules which stimulate the immune system.
Checkpoint inhibitors – These release the brakes on the immune system, i.e. PD-1/PD-L1 PARP inhibitors.
Immunomodulating drugs – Cause a boost to the immune system, i.e. Thalidomide
As cancer comes from within, it is ironic that the ultimate cure may also come from within. Many of these advances are made possible by work of pathologists.