PIK3CA and neoplasm: These include meningiomas with mutations in AKT1, PIK3CA, POLR2A, SMO, KLF4, and POLR2A, TRAF7. Mutations in these genes have been shown to correlate with tumor location and, in some cases, determine histologic subtype of meningioma or inform tumor behavior (6, 16, 26, 27).