CDKN2A and central nervous system cancer: To establish a tumor-derived glioma cell line carrying the BrafV600E mutation and deficient for Cdkn2a, we injected adenovirus expressing cre recombinase (Ad-cre) into the corpus callosum of ten week-old, cre-conditional, FVB/N BrafCA/+Ink4a/ArfLoxP/LoxP (fl/fl)transgenic mice (Figure 1A).