Human brain tumor cells implanted in mice were successfully eradicated after weeks of a novel treatment using an FDA-approved drug. The discovery is being hailed as a boon to brain cancer research, but scientists caution that many treatments have cured mice but then failed in humans.

Still, the researchers say they are inspired to quickly bring a human version of their new method into clinical trials.

In 2008, a team of cancer researchers from Johns Hopkins University identified brain tumors called gliomas. Building on that discovery, the research team targeted a specific mutation in the IDH1 gene of tumor's genetic code. This gene mutation, which occurs along a single spot a long chain of genetic code, is found in a many as 80 percent of lower-grade and progressive forms of brain cancer. The mutation forms and maintains cancer cells by hijacking proteins and transforming them into new molecules normally not found in the cells.

By repurposing the drug 5-azacytidine, which is approved to treat a pre-leukemia condition called myelodysplastic syndrome, the researchers were able to completely halt the growth of the brain cancer cells, and after 14 weeks of treatment the tumor cells were in complete regression.

"Usually in the lab, we're happy to see a drug slow down tumor growth," said Alexandra Borodovsky, a graduate student in the Cellular and Molecular Medicine Program at the Johns Hopkins University School of Medicine who performed the experiments. "We never expect tumors to regress, but that is exactly what happened here."

The type of tumor targeted by the research team eventually progresses to a form known as progressive or secondary glioblastoma, which is the deadliest form of brain cancer. The researchers hope their work will eventually lead to breakthrough cancer treatments in humans.

"This therapy has worked amazingly well in these mice," said study leader Dr. Gregory J. Riggins, a professor of neurosurgery and oncology at the Johns Hopkins University School of Medicine. "We have spoken with neurosurgeons here, and as soon as possible, we want to start discussing the parameters of a clinical trial to see if this will work in our patients as a follow-up to surgery."

An article highlighting Riggins and his colleagues' work is published in the open-access journal Oncotarget.