NF1 and malignant peripheral nerve sheath tumor: In patients with MPNST, inactivating mutations in the Neurofibromin 1 gene may cause loss of neurofibromin (Ras‐inhibiting enzyme); activation of Ras and downstream pathways causes upregulation of PI3K/AKT/mTOR/MAPK signal transduction, which for example regulates tumor proliferation and angiogenesis [5].