KLF4 and meningioma: Among all altered genes, NF2 is by far the most frequently mutated (0–46%) in the literature (4, 6, 8, 9, 12, 15, 27–29), followed by the TRAF7 (2–38%) (4, 12, 13, 30), AKT1 (8–31%) (6, 7, 12, 13, 15, 31, 32), KLF4 (9–15%; 100% of secretory meningiomas) (12, 13, 30, 32), SMO (6–32%) (7, 10, 12, 15), TERT (2–14%) (10, 33–38), and PIK3CA (0–7%) (10, 12, 39) genes, and other less studied genes, such as the ARID1B, POLR2A, and PTEN genes found to be mutated in 22, 6, and 1% of meningiomas, respectively (4, 5, 40).