CDKN2A and meningioma: PGDS promotor-directed bi-allelic inactivation of Nf2 led to the development of both meningothelial and fibroblastic meningiomas, whereas additional nullizygosity for p16Ink4a or p53 did not increase the number or malignancy grade of meningiomas (Figure 2, Table 3) [59,68].