Canadian scientists uncover hidden cells fueling brain cancer — and a drug that could stop them

Hamilton, ON (January 21, 2026) – A team of Canadian scientists has uncovered a new way to slow the growth of glioblastoma, the most aggressive and currently incurable form of brain cancer – and identified an existing medication that could treat it.

The research shows that certain brain cells – once thought to simply support healthy nerve function – actually help glioblastoma grow and spread. The researchers discovered that these cells send signals that strengthen the tumour, but when they blocked this harmful communication in lab models, the cancer slowed its growth significantly.

Even more promising, the study suggests that an existing HIV medication could be repurposed to target this process and offer a new treatment option for patients who currently have few. The prognosis for glioblastoma is poor, with survival often measured in months.

The research was published on Jan. 21, 2026 in Neuron and led by scientists at McMaster University and The Hospital for Sick Children (SickKids). Co-first authors of the study are Kui Zhai, a research associate in the Singh Lab at McMaster, and Nick Mikolajewicz, a postdoctoral fellow in the Moffat Lab at SickKids at the time of the study.

“Glioblastoma isn’t just a mass of cancer cells, it’s an ecosystem,” says Sheila Singh, co-senior author of the study and professor of surgery at McMaster University. “By decoding how these cells talk to each other, we’ve found a vulnerability that could be targeted with a drug that’s already on the market,” adds Singh, who is also director of the Centre for Discovery in Cancer Research at McMaster.

It's known that glioblastoma grows by forming a network of cells that communicate and support each other, and disrupting these connections can slow the cancer. This study dug deeper to uncover which brain cells are involved. The researchers discovered that a type of cell called an oligodendrocyte, normally responsible for protecting nerve fibers, can switch roles and actually support tumour growth. These helper cells communicate with cancer cells through a specific signaling system, creating an environment that allows the tumour to thrive. When researchers blocked this communication in lab models, the cancer slowed down significantly, showing that this interaction is critical for glioblastoma’s survival.

What makes this finding especially promising is that the signaling system involves a receptor called CCR5, which is already targeted by an existing HIV medicine called Maraviroc. This means a medication that’s already approved and widely used could potentially be repurposed to treat glioblastoma, offering hope for faster progress toward new therapies.

“The cellular ecosystem within glioblastoma is far more dynamic than previously understood. In uncovering an important piece of the cancer’s biology, we also identified a potential therapeutic target that could be addressed with an existing drug. This finding opens a promising path to explore whether blocking this pathway can speed progress toward new treatment options for patients,” said Jason Moffat, co-senior author of the study, senior scientist and head of the Genetics & Genome Biology program at SickKids.

The breakthrough builds on Singh and Moffat’s 2024 study published in Nature Medicine, which discovered that a migration path used by cells during brain development can be hijacked for cancer cell invasion. Together, these discoveries highlight a new era of glioblastoma research focused on dismantling the tumour’s complex communication networks.

This research work was supported by the 2020 William Donald Nash Brain Tumour Research Fellowship and the Canadian Institutes for Health Research. Singh is a Tier 1 Canada Research Chair in Human Cancer Stem Cell Biology and Moffat is the GlaxoSmithKline Chair in Genetics & Genome Biology at The Hospital for Sick Children.