Researchers from Pennsylvania State University have identified a molecule, known as TIC10, which activates a protein that helps fight the disease, the Daily Mail reported.
The protein, called TRAIL, suppresses tumour development during immune surveillance, the immune system's process of patrolling the body for cancer cells.
This process is lost during cancer progression, which leads to uncontrolled growth and spread of tumours.
The key benefit of using TRAIL (tumour-necrosis-factor-related apoptosis-inducing ligand) as a way to fight cancer is that it is already part of the immune system, so it is not toxic to the body like chemotherapy or radiotherapy.
Furthermore, the small size of TIC10 also makes it more effective than past discoveries because it can cross the blood-brain barrier, which separates the main circulatory system from the brain.
This barrier can prevent cancer treatments from entering the brain, thereby hindering the action of drugs for brain tumours.
"We didn't actually anticipate that this molecule would be able to treat brain tumours - that was a pleasant surprise," lead researcher Wafik El-Deiry, an oncologist at Pennsylvania State University said.
Another positive is that TIC10 does not just activate the TRAIL gene in cancerous cells, but also in healthy ones. This is known as the "bystander effect" - i.e. where cells near cancerous cells are also killed.
Nearby healthy cells are also given a boost to increase the number of cancer-killing TRAIL receptors on their cell surface.
Although the study was limited to mice, Dr El-Deiry is confident that a similar approach would work in humans.
The success of TRAIL to trigger cancer cell death has led to ongoing clinical trials with artificially created versions, and early trials have shown that giving the protein in drug form is safe.
The study is published in the journal Science Translational Medicine.