A chemical that makes brain tumors glow pink could help surgeons safely remove the cancer, suggests a study.
Scientists gave people with suspected glioma a drink containing 5-ALA, a substance that accumulates in fast-growing cancer cells.
The pink glow of the chemical causes has been found in people with the most aggressive cancers.
The researchers hope that it will be easier for surgeons to differentiate between cancer cells and healthy brain tissue.
The treatment of glioma, the most common type of brain tumor, and those killed by the former minister of the Ministry, Ms. Tessa Jowell, usually involves surgery to remove as much cancer as possible, and the prognosis for patients is often bad.
For this new study, 99 patients with suspected high-grade (fast-growing) glioma before surgery received a 5-ALA drink.
Research has previously shown that 5-ALA ends up in fast-growing cancer cells because they lack an enzyme needed to break down the chemical.
Surgeons used microscopes to help them search for fluorescent tissue while removing tumors from the patient's brain.
During their surgery, surgeons reported seeing fluorescence in 85 patients.
Of these, 81 were confirmed by pathologists to be suffering from a high grade disease, one had a low grade disease and three could not be evaluated.
In the 14 patients, in which surgeons did not observe fluorescence, seven tumors were identified as low-grade gliomas, while the other seven could not be assessed.
Study author Dr. Kathreena Kurian, Professor of Brain Tumor Research at the University of Bristol, said: "There is an urgent need to have something while the patient is on the table while the neurosurgeon is operating, which will make him find the worst bits.
"The beauty of 5-ALA is that they can see where high grade gliomas are while operating."
The researchers warn that the study focused on patients who were already thought to have high-grade tumors, and a larger study in which more patients had low-grade disease would provide more information on how to use this technique.
Other types of markers may need to be tested to detect low-grade glioma cells, it is said.
The next steps could be testing 5-ALA in children with brain tumors or assisting surgeons in tumor and scar tissue in adult patients whose brain tumor has returned after treatment.
Dr. Paul Brennan of Cancer Research UK said: "By highlighting the more aggressive tumor cells in real time, physicians could achieve the delicate balance by removing as much tumor as possible while preserving the surrounding healthy tissue.
"The fluorescent marker may also facilitate post-treatment, as cancer cells left behind after surgery may require additional radiotherapy or chemotherapy."
The National Institute of Health and Clinical Excellence approved the use of 5-ALA for patients with brain tumors earlier this year before surgery.
The research will be presented at the NCRI Cancer Conference 2018 in Glasgow from 4 to 6 November.