AKT1 and meningioma: Three types were delineated: type A rarely recurring malignancies that carry mutations in TRAF7, AKT1, or KLF4 but do not exhibit chromosomal deletions; type B meningiomas that lack the chromatin-modifying enzyme PRC2 and are deficient in the NF2/Merlin protein; and type C, which is both NF2-deficient and marked by CIN, notably the loss of chromosome 1p, and this type has worse recurrence rates [42,44].