AKT1 and malignant peripheral nerve sheath tumor: 8,9 Others employed Sleeping Beauty transposon-based mutagenesis in p53 mutant mice with overexpressed EGFR to identify cooperating mutations in MPNST pathogenesis.10 Alterations in Wnt/β-catenin, PI3K-AKT-mTOR, and growth factor receptor signaling pathways were found to promote tumorigenesis in concert with p53 loss and EGFR activation.