Can the Polio Vaccine Really Fight Brain Tumors?

Franklin Delano Roosevelt, the United States’ longest-serving president, was known for many things: architect of his country’s World War II victory, savior of the Great Depression, last sitting president to die in office of natural causes. What many casual students of history don’t remember is that FDR was confined to a wheelchair in the later years of his life due to a childhood battle with polio, a then-common viral affliction that can cause permanent nerve and muscle damage.

Today, polio is unheard of among Americans of any age. The disease has been all but eradicated in most of the world, a microbiological victory that stands nearly alone with the eradication of smallpox as a total win for public health. The most potent weapon in the fight against polio was the polio vaccine, which empowers the immune system to rally against invading polio viruses.

Today, the urgency around polio is gone, and the polio vaccine’s original purpose has largely been fulfilled. But science may have found a new use for this cure — one that could prove just as game-changing as the near-eradication of polio itself. According to recent research, the polio vaccine shows tremendous promise in the fight against certain brain tumors, though it might be a bit premature to say that the vaccine actually cures brain tumors. Here’s what we know — and what could be coming down the road in the years to come.

Cancer’s Acquired Defenses

Malignant tumors are truly devious in their ability to evade the body’s impressive natural defenses. Over time, cancer cells develop molecular defenses — in simplified terms, complex protein coatings — that literally render them invisible to the human immune system. Cancer’s invisibility allows it to grow without facing overwhelming resistance.

Glioblastoma, a particularly deadly form of brain cancer, is no different. Until very recently, a glioblastoma diagnosis was little better than a death sentence; the condition’s five-year survival rate is truly abysmal. While glioblastoma remains one of the most difficult forms of cancer to treat, genetically engineered polio viruses may provide some hope for at least some sufferers.

How Engineered Polio Viruses Disarm Tumor Cells

These engineered polio viruses, part of the “oncolytic virus treatment” family, turn cancer cells’ natural defenses against them. First, the virus breaks through each cell’s natural defenses, causing an infection that cripples and ultimately kills them. While this process is certainly beneficial for patients, the real benefit of the oncolytic treatment is the engineered virus’s ability to recruit the body’s immune system to attack cancer cells. Initially, the immune system is spurred to action by the presence of polio viruses, but its activities over time appear to stall and even reverse the growth of tumors.

What’s Next for Brain Cancer Treatment?

Per Duke University, the concept of cancer-fighting viruses has existed for at least 100 years, but we’ve only been able to manipulate viral genomes effectively since the late 20th century. The polio virus treatment is one of the first truly promising oncolytic viruses. If its early promise pans out, it’s basically a foregone conclusion that similar treatments — possibly for glioblastoma, possibly for other tricky forms of cancer — will follow.

Oncolytic polio viruses aren’t the only promising avenue for brain cancer treatment, of course. Advances in targeted radiotherapy, such as Gamma Knife radiosurgery treatments, have made it possible to target small tumors deep within the brain without damaging surrounding tissue. Customized therapies that leverage the human immune system are gaining steam as well.

Such advances are likely to accelerate in the years to come. One day in the not too distant future, the now near-miraculous oncolytic polio virus treatment could well seem primitive and blunt.

Never a Panacea

Last century, the polio vaccine helped eliminate one of the world’s most common and devastating childhood diseases. This century, it could dramatically improve our ability to combat devastating brain tumors.
But it’s important to note that the polio vaccine isn’t a panacea. It’s proven effective at preventing one particular disease, and may soon help fight a handful of closely related cancers. Unfortunately, there’s no evidence that the polio vaccine can fight any other types of cancers or prevent other viral infections that still plague humanity. In short, it’s just one more weapon in our medical arsenal — not a weapon to end all wars, as the world’s most famous polio sufferer infamously said about another revolutionary technology developed under his watch.