What are cancer vaccines?Vaccines are medicines given to healthy people to help prevent infections, such as measles and chicken pox. They help train the immune system to recognize and destroy harmful substances. Similar to traditional vaccines, cancer vaccines target infectious agents that cause or contribute to the development of cancer, according to the National Cancer Institute (NCI).
Cancer vaccines are composed of three components:
- Immunogene which stimulates immune cells
- Delivery system which targets immunogene to specific immune cells called “ Antigen Presenting Cells”
- Adjuvant which potentiate immune reaction.
Types of Cancer Vaccines:
- Prevention Vaccines
- Treatment Vaccines
Cancer Prevention Vaccines:
Many people might not realize it, but some cancers are caused by viruses. Vaccines that help protect against infections with these viruses might also help prevent some of these cancers. A person has to get the vaccine before the virus infects him or her. Otherwise, the vaccine work.There are three cancer prevention vaccines approved by the U.S. Food and Drug Administration (FDA):
The FDA approved Gardasil for people ages 9 to 26 to prevent Cervical, Vaginal and Vulvar cancers in girls and women and Anal cancer in women and men and Genital warts in men and boys. The vaccine protects against the Human Papillomavirus (HPV). If the virus is long lasting, it can cause cancers of some organs. HPV can also cause other cancers but the FDA hasn't approved the vaccine for, such as oral cancer. This vaccine also protects against HPV infection. The FDA approved it for the prevention of cervical cancer in girls and women ages 10 to 25.
The vaccine prevents hepatitis B virus (HBV) infection. Long lasting infection with HBV can cause liver cancer. This is the first cancer prevention vaccine which was approved by FDA in 1981.
Cancer Treatment Vaccines
Cancer treatment vaccines also called therapeutic vaccines are a type of immunotherapy. The vaccines work to boost the body's natural defenses to fight a cancer. Doctors give treatment vaccines to people already diagnosed with cancer. The vaccines may:
- Prevent the cancer from coming back
- Destroy any cancer cells still in the body after other treatment
- Stop a tumor from growing and spreading
Sipuleucel-T ( Provenge®)
Most cancer treatment vaccines are only available through clinical trials, which are research studies involving volunteers. However, in 2010, the FDA approved sipuleucel-T ( Provenge®) for men with metastatic prostate cancer, which means the cancer has spread from the prostate to other parts of the body. Sipuleucel-T ( Provenge®) is customized for each patient through a series of steps.
- First white blood cells are removed from the patient’s blood. White blood cells help the body fight infections and diseases.
- Then the researcher modifies the white blood cells in a laboratory to recognize and targets prostate cancer cells.
- Next the modified cells are put back into the patient through a vein. This is a similar to a blood transfusion. The modified cells teach the immune system to find and destroy prostate cancer cells.
Clinical trials are important for learning more about cancer vaccines. Researchers are testing vaccines for several cancers including Bladder, Brain, Breast, Colorectal, Kidney, Lung cancer and Melanoma etc. But they are not yet approved for prevention and treatment of cancer.
In general, cancer treatment includes surgery, radiation therapy, chemotherapy, hormones and monoclonal antibodies either alone or in combination. But these vaccines are for prevention and treatment also which carry a new hope for life.