Harvard Medical School scientists have successfully created cancer fighting stem cells.
The genetically engineered cells are designed to fight brain cancer without killing normal cells or harming themselves. The research, published in the journal Stem Cells, showed the technique worked on mice but it has not been replicated in humans.
Lead author Dr Khalid Shah said: "Now, we have toxin-resistant stem cells that can make and release cancer-killing drugs."
Cancer Research UK's Nell Barrie told the BBC it was an "ingenious approach" but warned much work would be needed before we could know if the research would help humans. "We urgently need better treatments for brain tumours and this could help direct treatment to exactly where it's needed.
"But so far the technique has only been tested in mice and on cancer cells in the lab, so much more work will need to be done before we'll know if it could help patients with brain tumours."