CDKN2A and glioma: In a landmark study by Becher et al., the RCAS/t-va system was used to overexpress platelet-derived growth factor B (PDGF-B) in Nestin-expressing progenitors within the neonatal brainstem to promote cell proliferation, combined with Ink4a-ARF deletion which removes tumor suppressor functions, driving glioma formation [45].