CDKN2A and neoplasm: However, patients with a WHO grade 2 meningioma with a heterozygous CDKN2A/B deletion (n = 7) had a median time to tumor progression of 25.1 months (95% CI 0.0–58.2 months), and those with a WHO grade 3 meningioma with a CDKN2A/B wild-type status had a median time to meningioma progression of 32.0 months (95% CI 25.1–38.9 months).