As predicted, double CKO (dCKO) of both Ascl1 and Olig2 prevented tumor formation in approximately 80% of TNP-deleted mice (N = 16/20, 4 litters) (Fig. 2p, q), while 20% developed slow-growing tumors that were not lethal until 4-6 months of age (Fig. 2r–t). This evidence concerns the gene OLIG2 and neoplasm.