POLR2A and meningioma: However, mutations in TRAF7 can be present in isolation, though often they can co-occur with KLF4, AKT1, or PIK3CA mutations, whereas mutations in SMO and POLR2A are usually mutually exclusive (16, 79) Interestingly, the meningiomas arising from SMO and AKT1-MTOR aberrations often arise in the skull base (68).