Moreover, PDGFB-induced glioma primary cells (PIGPC) derived from RCAS-PDGFB-induced gliomas in Nestin-tv-a Ink4a/Arf-/- mice showed increased colony numbers, as well as visibly larger colonies when cultured on ADM1 compared to colonies formed on ADM21 (Figure 4C). This evidence concerns the gene CDKN2A and central nervous system cancer.