Viruses like polio and measles can be dangerous and even deadly. This is why countries all over the world have worked to create vaccines to eradicate or slow the progress of these viruses. But researchers are beginning to use genetically modified versions of these viruses to treat illnesses. This treatment is called oncolytic virotherapy, and it could be a cure for cancer.
How does oncolytic virotherapy work?
Researchers at the MD Anderson Cancer Center at the University of Texas began using oncolytic virotherapy in 2015 to treat Glioblastoma Multiforme, the most aggressive type of brain cancer. The current treatment protocol for glioblastoma includes surgery, radiation, and chemotherapy, but these aggressive tumors remain incredibly fatal despite these treatment options.
Oncolytic virotherapy works by genetically modifying viruses to ignore healthy tissue and only target a specific protein within cancer cells. Once the virus locates this protein, it replicates continuously until it causes the cancer cells to explode. Once the cancer cell explodes, the virus is released back into the bloodstream and locates another cancer cell to continue the process.
In other words, the part of the virus that makes people sick is removed, but the body still recognizes the virus as a foreign substance, triggering the immune system to attack the cancer.
Furthermore, the virus stays in the body of the patient. If the cancer comes back, the virus will seek out the new cancer cells and destroy them.
Which viruses are being used to fight cancer?
It may sound counterintuitive to use a virus to cure cancer, but several medical institutions are backing the cutting-edge treatment and furthering its development. Here are the main viruses being developed as a cure for cancer.
- Polio virus. Researchers at Duke University are using the polio virus to treat glioblastoma by inserting a live, genetically modified version of the virus directly into the tumor. The researchers adapted the virus by removing the viral disease from it, leaving behind the part of the virus strong enough to penetrate cancer cells and encourage the immune system to target the tumor. The overall rate of survival for glioblastoma is about 4 percent in the general population, but this treatment increases survival rates to 21 percent.
- Herpes virus. Talimogene Laherparepvec (TVEC), also called herpes simplex virus, has been approved by the FDA to treat melanoma. The virus has been genetically modified to shrink the tumor or tumors, and activate the immune system to destroy the cancer cells.
- Common cold virus. Cocksackie virus (CVA21) is one strand of the common cold being used to attack and kill bladder cancer. In a study at the University of Surrey in England, 15 patients had their tumors injected with this virus one week prior to surgery. When the removed tumors were analyzed after surgery, there was evidence that the virus had targeted and killed some of the tumor cells in all 15 patients with no apparent side effects.
- Measles virus. Also known as Rubeola, this virus in its natural state can cause fever, rash, and respiratory symptoms. Measles has also recently made a comeback in the United States after being declared eradicated in 2000. The Mayo clinic used a large dose of this virus to treat cases of multiple myeloma after patients’ tumors failed to respond to traditional forms of therapy. The researchers injected 100 billion units of the virus, which would have been enough to infect 10 million people had it not been genetically modified. While previous therapies injected the virus directly into the tumor, this virus was administered intravenously in order to treat metastatic cancer that had spread to surrounding areas of the body.
Is a cancer vaccine on the horizon?
Not yet, but Dr. Elizabeth M. Jaffee of the Cancer Immunology Program and the Gastrointestinal Cancers Program at Johns Hopkins and the Sidney Kimmel Comprehensive Cancer Center is working on a vaccine for pancreatic cancer.
Pancreatic cancer has one of the lowest rates of survival, but this vaccine may be able to give patients a better prognosis. At its current stage, this vaccine is being used to treat patients who have had pancreatic tumors removed through surgery but are at risk of the cancer returning.
The initial trials have demonstrated that the vaccine is safe and allows the immune system to activate. So far, the patients treated with this vaccine have remained disease-free.
Some of these treatment methods are still in the investigation stage and have not been approved by the FDA. However, cancer therapy is evolving at rapid rates, and these methods of fighting cancer appear promising.