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Getting the latest healthcare news for you
Getting the latest healthcare news for you

Scientists at St. Jude have figured out why a single mutation causes brain tumors almost exclusively in the brainstem and other midline regions. The H3.3 K27M mutation keeps brainstem cells in an immature, rapidly dividing state longer than cells elsewhere — creating a prime environment for tumor growth. The findings, published in Nature Communications, could open new doors for targeted therapies against diffuse midline glioma (DMG).
Scientists at St. Jude Children's Research Hospital have uncovered a key reason why diffuse midline glioma (DMG) — a devastating pediatric brain cancer with no effective treatments — tends to arise specifically in the brainstem and other midline brain structures. The culprit is a mutation called H3.3 K27M, which alters how DNA is packaged inside cells. While this mutation can affect cells throughout the body, it was long unclear why it drives cancer almost exclusively in the brain's midline.
The research team compared oligodendrocyte precursor cells (OPCs) — cells that help produce the insulating material around nerve fibers — from the brainstem versus other brain regions. They found that while the mutation changes DNA packaging similarly across regions, its downstream effects are strikingly different: in brainstem OPCs, H3.3 K27M keeps cells in an immature, actively dividing state for longer, creating a wider window for tumor formation. Developmental signaling pathways were also more disrupted in brainstem cells.
Key Takeaways:
Why it matters: DMG is one of the most lethal childhood brain cancers, and current treatments offer little benefit. By revealing how this mutation exploits region-specific developmental biology, this study lays the groundwork for therapies precisely tailored to how DMG actually forms.