One of these such lines is IOMM-Lee,established from an intraosseous CNS WHO grade 3 meningioma, and is still commonly utilized due to its ability to readily form heterotopic and orthotopic xenografts.359–361 Although it harbors CDKN2A/B loss as a hallmark of proliferation in addition to a high burden of copy number changes, it lacks the biallelic NF2 inactivation seen in the majority of biologically aggressive meningiomas and also contains unusual chromosomal gains of 3q, 5, and 9 that are not commonly found in meningiomas. The gene discussed is NF2; the disease is meningioma.