Proteo-metabolomic analysis of plasma exosomes identifies novel biomarkers of thrombo-inflammation and disease progression in pediatric neuroblastoma

Neuroblastoma (NB) is a heterogeneous pediatric solid tumor in which minimally invasive biomarkers that reflect tumor biology and treatment response remain limited. Plasma exosomes contain proteins and metabolites that may provide insight into neuroblastoma pathophysiology and enable the identification of mechanistically linked biomarkers. This study employed an integrated proteo-metabolomic approach to identify novel exosomal biomarkers associated with disease status. Plasma samples were obtained from 14 patients with neuroblastoma before tumor resection (on-disease), 15 patients after tumor resection (follow-up), and 20 healthy donors. Plasma exosomes were characterized by transmission electron microscopy, nanoparticle tracking analysis, and immunoblotting. SWATH-targeted proteomic profiling identified 16 significantly altered exosomal proteins, and bioinformatic analysis revealed platelet activation, coagulation cascades, and growth-related signaling, all centralized on exosomal alpha-2-macroglobulin (A2M), which showed the highest level in the on-disease group and declined in the follow-up and healthy control groups.