<p>Nature Genetics, Published online: 09 February 2026; <a href="https://www.nature.com/articles/s41588-025-02476-9">doi:10.1038/s41588-025-02476-9</a></p>By investigating single-cell gene expression and DNA methylation profiles of meningiomas, we found that the composition of the tumor microenvironment and cellular activation status both correlate with tumor aggressiveness. These findings explain the outcomes of previous DNA methylation-based classification approaches to meningioma and have direct clinical applicability.