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Researchers say that poliovirus can help treat brain cancer

    Abdulaziz Sobh
    By Abdulaziz Sobh

    Categories: Health


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    Glioblastoma is a type of brain cancer that has recently been quite visible in the media after Senator John McCain received treatment for it. Glioblastoma claimed the lives of more than 15,000 people in 2015. However, researchers at Duke University are working to reduce that number through the "oncolytic virus therapy" of an unexpected medical foe: the poliovirus.

    What is oncolytic cancer therapy?

    It is a type of treatment in a branch of cancer care called immunotherapy where human viruses, which can fight cancer in different ways, are modified in a laboratory and used to fight cancer. Through therapy with the oncolytic virus, viruses can stimulate the immune system, the same system that fights diseases like the flu, to also attack cancer. With this particular form of therapy, viruses can also infect cancer cells, causing them to separate and die.

    Viral therapy emerged many years ago when spontaneous tumor remissions occurred after immunizations with live and weakened viruses. Studies using viral therapy in lung cancer and melanoma have been conducted with a real viral therapy approved for melanoma by the US Food and Drug Administration. UU (FDA) in 2016.

    Why use it to treat this brain cancer?

    Brain cancers are rare, but if someone develops brain cancer, it is likely to be glioblastoma. Unfortunately, it has a poor prognosis, with most patients dying approximately 14 months after it is diagnosed.

    Not only because of the high tendency to malignancy, but also because of its resistance to current treatments against cancer: surgery, radiation, and chemotherapy.

    The reality of glioblastoma prognosis has caused some patients to choose to end their lives shortly after diagnosis. New treatments are desperately needed, and this particular type of cancer has characteristics that make it an ideal candidate for viral therapy.

    How does everything work?

    A live poliovirus is used, weakened by a process in the laboratory. It is important to keep in mind that live and weakened viruses have been common for years and are critical components of many vaccines around the world, such as poliovirus.

    In the case of oncolytic virus therapy, the polio virus is genetically modified to function as its normal viral being but it does not have the capacity to cause its "normal" disease. The part that causes poliovirus disease, infamous for causing a devastating neurological disease, is removed and replaced with a part that is harmless.

    For the immune system, it looks like "real polio," but it does not have the ability to cause the disease, or even mutate to anything that might cause it. This is important since the modified virus has to maintain the ability to affect the same target, the brain.

    The virus is also modified to include components that would stimulate one's immune system to fight. Patients with glioblastoma often have an immune system that malfunctions, both from disease and from treatments such as radiation that deactivates immunity. By inserting a new segment in the virus, such as the common cold, the immune system is activated without any real disease. A strong reaction of the immune system attracts the cells to cancer to attack it.

    Because cancer cells work differently than normal cells, the genetically modified virus interacts differently with cancer and non-cancer cells. The cancer cells of glioblastoma have different chemical components than the non-cancerous brain cells. The genetically modified poliovirus has the ability to attack cancer cells, infect and control the machinery of the cell, and encourage an attack on a person's unique immune system. It does this by leaving the non-cancerous cells intact.

    Why use poliovirus?

    Human viruses are unique, evolved in conjunction with the human immune system, teaching them to recognize and kill infected and abnormal cells. Poliovirus has a large size of RNA (RNA is a genetic component), compared to other viruses, so researchers can play with their parts in genetic manipulation. It also has a limited lifespan in humans, unlike other viruses, such as chicken pox. Therefore, it has the potential to be used to treat a number of different types of cancers.

    What have been some of the results?

    Using polio as a "virus that kills cancer," Duke researchers have seen a survival rate of about 21 percent in brain cancer patients who received poliovirus oncolytic virus therapy. Survival was only 4 percent for those who did not receive it. does not receive therapy treatment.

    The therapy has been administered locally at the site of the brain tumor through a special catheter. This allows a greater "seeding" of the virus in the tumor cells and does not spread throughout the body. Many patients have been able to tolerate poliovirus therapy well, but some have had side effects such as seizures, headaches and speech problems. The too much inflammatory response can be a bad thing. Higher doses of poliovirus therapy treatment were associated with more inflammation in the brain. Researchers have been working to address the dosage and minimize inflammation without compromising the boost of the immune system through the use of bevacizumab, a medication that minimizes inflammation during viral treatment.

    Poliovirus therapy is still in clinical trials and is not yet ready for the general public. The big questions are the potential cost since some current viral therapies cost around $ 60,000 per treatment and the ability of hospitals to transport stores, and discarding these medications is a concern for patients and providers.

    Where can you learn more?

    Immunotherapy remains a developing field. Talking to a medical professional and keeping up with the results of quality sources, such as the Centers for Disease Control and Prevention (CDC) and the American Cancer Society, are important ways to get more information.