Malignant peripheral nerve sheath tumors (MPNSTs) are very rare cancers with five-year survival rate<50%. About half occur in patients with neurofibromatosis type 1 (NF1), a progressive autosomal dominant tumor syndrome characterized by benign Schwann cell tumors (neurofibromas). Neurofibromas affecting larger nerves are called plexiform; these have an 8-13% risk of transformation to MPNST. There is no evidence-based treatment protocol for MPNST, so institutions manage patients with variable modalities. In addition, neuropathologists lack advanced tools for diagnosis and prognosis. The goal of this work is: (1) to gather retrospective chart review data on MPNST cases treated at the University of Florida (UF) College of Medicine (Aim 1), and (2) to immunostain MPNST sections for two antigens (Aim2). The first Aim will provide data about UF therapeutic approach outcomes. The second Aim will test for relationships between H3K27me3 and HMGA2 immunostaining results with survival. This work involves retrospective chart review and analysis of existing specimens.