The prevalence of meningiomas with homozygous CDKN2A/B deletions significantly increased with the WHO grades (Fig. 2d–f): 0.002 (95% CI − 0.001–0.004) of WHO grade 1 meningiomas showed a homozygous CDKN2A/B deletion compared to 0.039 (95% CI 0.021–0.056) of WHO grade 2 meningiomas and 0.290 (95% CI 0.196–0.384) of WHO grade 3 meningiomas (p < 0.00001). The gene discussed is CDKN2A; the disease is meningioma.