To address the function of EGFR-Ras and PI3K in glioma, we analyzed the genetic basis of glial pathogenesis in our repo>dEGFRλ;dp110CAAX model, as this model shows robust neoplasia, similarity to human tumor genotypes, and sensitivity to dEGFR and dPTEN gene dosage (data not shown). The gene discussed is PIK3CA; the disease is glioma.