SPRED1 and neoplasm: We next decided to explore the putative tumor suppressive effects of genes not previously linked to gliomagenesis, but strongly implicated by our mutational analysis and piggyBac experiments—Tead2, Nav3, and Spred1. We performed CRISPR-Cas9 knockout experiments using ex vivo EGFRvIII-gliomaspheres derived from mouse GBMs.