CDKN2A and meningioma: RFS was significantly shorter in patients with meningiomas IHC-G2 or IHC-G3 (hazard ratio, 2.3; 95% confidence interval, 1–5.1; P = 0.032) (Fig. 4) or having mitotic index ≥ 4/1.6 mm2 (hazard ratio, 2.8; 95% confidence interval, 1.4–5.5; P = 0.0026) or harboring CDKN2A HeDe (hazard ratio, 5; 95% confidence interval, 2.1–12.1; P = 0.0003) (Fig. 4).