NF2 and meningioma: These findings seem to support the concept of either 4 distinct MGs matching those discovered by Nassiri et al. or 3 epigenetic groups with one group that could be further split into 2 subgroups with distinct clinical outcomes and gene expression signatures.117 Bayley et al. also found 3 methylation groups of meningioma based on integration of DNA methylation, RNA expression, NF2 status, and degree of chromosomal instability in a cohort of primary CNS WHO grade 1 and 2 meningiomas.