NF2 and neoplasm: Lastly, they combined PDGF-B;Nf2;CDKN2AB lesions and found an even higher tumor take rate of 79% (54–94%) with 33% grade 1, 47% grade 2, and 20% grade 3 (but the same applies here as with the above CDKN2A/B−/− in relation to the malignancy grade).