NOTCH1 and neoplasm: To test this, we generated two genetic murine glioma models by injecting an HA tagged PDGFB-IRES-Cre expressing retrovirus to target progenitor cells in the subcortical white matter of p53fl/fl mice (Eyler et al, 2020), with one of the models harboring a constitutively-active form of Notch1 in transformed cells at tumor inception (Fig. 1A).