Diffuse midline glioma is among the most devastating childhood brain tumours, infiltrating vital structures and leaving clinicians with very limited treatment options. Research from Karolinska Institutet's Institute of Environmental Medicine, published in Cell Death and Disease by the group of Bertrand Joseph, points to an unexpected accomplice in the tumour's spread: microglia, the brain's own resident immune cells.
When exposed to tumour cells, microglia began producing large amounts of extracellular matrix proteins, most prominently fibronectin, effectively laying down scaffolding through brain tissue. Analyses of patient samples and single-cell datasets showed that microglia, not the cancer cells themselves, were the main source of fibronectin in these tumours. In laboratory experiments, microglia-derived fibronectin increased the tumour cells' capacity to invade surrounding tissue, and blocking fibronectin chemically or genetically clearly reduced that invasiveness.
The clinical correlation strengthens the case: high levels of fibronectin and related matrix proteins were associated with poorer prognosis across several independent patient cohorts. The authors suggest fibronectin could represent a therapeutic target in a disease where none has yet translated into effective treatment, while noting candidly that no such therapy currently exists. The work reframes the tumour microenvironment as an active driver, not a bystander, in childhood brain cancer.