Spatial gene expression profiling unveils immuno-oncogenic programs of NF1-associated peripheral nerve sheath tumor progression

Plexiform neurofibromas (PNF) are benign peripheral nerve sheath tumors (PNST) that arise in persons with neurofibromatosis type 1 (NF1). Despite similar histological appearance, these neoplasms proceed along diverse evolutionary trajectories, with a subset progressing to a devastating form of sarcoma called malignant peripheral nerve sheath tumor (MPNST), the leading cause of premature death in individuals with NF1. Malignant transformation of PNF often occurs through the development of atypical neurofibroma (ANF) precursor lesions characterized by distinct histopathological features and CDKN2A copy number loss. While genomic studies have improved our understanding of key driver events promoting tumor progression, the transcriptional alterations that precede malignant transformation remain poorly understood. Here we resolve gene expression profiles in PNSTs across the neurofibroma-to-MPNST continuum in NF1 patients and genetically engineered mouse models, providing insight into nascent molecular features associated with neurofibroma evolution and transformation. These findings highlight the need for molecular diagnostic tools that augment conventional histopathological criteria to identify neurofibromas at high risk of undergoing malignant transformation, facilitating risk-adapted care. A cohort of n=35 peripheral nerve sheath tumor samples samples was assembled by retrospective review of the Indiana University Pathology archives. Tissues were microdissected from selected regions of interest conforming to consensus diagnostic criteria and subjected to RNA expression profiling across a high-content panel of genes involved in tumor progression, microenvironment, and immune response (PanCancer IO360TM Panel, NanoString Technologies).