NES and neoplasm: Similarly, the co-injection of the RCAS-PDGFB and RCAS-Ctrl-gRNA in adult Ntv-a; Nes-Cre; LSL-Cas9 and Gtv-a; hGFAP-Cre; LSL-Cas9 had a considerably limited tumor potential and no tumors were observed in our 120 days’ experimental timeframe.