Researchers have discovered that the Zika virus can kill tumor cells from glioblastoma cancers. Here’s how it does that.

The Zika virus is known to attack the developing brain of fetuses, leaving infants at risk for severe birth defects.

But scientists are now hoping they can harness this dangerous virus to reach the brain in adults and kill hard-to-treat tumors.

The Zika virus swept through the Western hemisphere last year infecting millions and resulting in thousands of infants being born with the birth defect microcephaly.

The virus’ ability to reach the brain in utero has also led researchers to theorize it could potentially be used to fight a malignant form of brain cancer in adults, called glioblastoma.

In a new study, published in the Journal of Experimental Medicine, researchers from Washington University School of Medicine, the Cleveland Clinic, University of San Diego, and other institutions studied how human glioblastoma cells reacted to exposure to the Zika virus.

They also infected mice with glioblastomas to the virus to see if the infection affected the tumor.

Glioblastomas are the most common form of primary brain cancer, or cancer that has not metastasized from other areas of the body.

Every year approximately 12,000 people are diagnosed with the condition. This year Arizona Senator John McCain made headlines with his glioblastoma diagnosis.

It’s a malignant form of cancer that kills most people within two years of diagnosis, even after surgery, chemotherapy, and radiation treatment.

In this study, the researchers wanted to see if Zika could potentially be used as a treatment to buy patients more time.

They exposed 18 mice with glioblastomas to the Zika virus and found that within two weeks the tumors were far smaller than those in the control group.

Additionally, they found that when they injected the virus into tumor cells, the virus infected and killed the stem cells in the tumor.

The findings are still preliminary, and the authors point out these findings would need to be replicated in patients with glioblastoma to verify the effects of the virus on these cancer cells.

Scientists hope these early results could mean that the Zika virus could be used in the future to help fight against glioblastoma.

“We see Zika one day being used in combination with current therapies to eradicate the whole tumor,” Dr. Milan G. Chheda, a senior author of the study and an assistant professor of medicine and neurology at Washington University School of Medicine, said in a statement.

Dr. Andrew Sloan, director of the Brain Tumor and Neuro-Oncology Center at University Hospitals Cleveland Medical Center, said that a patient with glioblastoma will usually have surgery to remove the tumor.

However, not even the best surgeon can get every microscopic cancer cell in the brain.

“Ninety-eight percent of the patients will die of the tumor, and 90 percent will have the tumor grow back between 1 to 2 centimeters of the primary tumor,” he explained.

Sloan explained that doctors believe it’s the stem cells — which make up a small fraction of tumor cells — that can cause the tumor to quickly grow back.

“Cancer stem cells might compromise between 2 to 5 percent of all the cells in the tumor,” Sloan told Healthline. “But these are cells that are very resistant to radiation and chemotherapy, and these are the cells that give rise to new tumors.”

Sloan said if the Zika virus targets the stem cells it might mean that the cancer doesn’t return in patients after surgery.

Sloan said doctors have been hoping to find a way to harness a virus to prime the immune system to fight cancer, but so far nothing has been a game changer for glioblastoma treatment.

“There’s been a lot of progress in immunotherapy,” Sloan said. “We think that’s probably the best bet, but we haven’t hit anything over the fence.”

He said he hopes that this early study could be the starting point for more research that could find a way to turn a deadly virus into a treatment.

“It’s very exciting and I think there’s a lot of potential for it,” he said.