Although Notch2 deletion does not accelerate hyperplasia formation in Trp53-/- mutants, it significantly accelerates the growth of PDGF+Trp53-/- gliomas [20], suggesting that a strong mitogenic stimulus, provided, for instance, by PDGF, is required to release the tumorigenic effects of Notch2 inhibition. Here, NOTCH2 is linked to central nervous system cancer.