MALDI-TOF Mass Spectrometry Profiling of Plasma Exosomes Evaluates Osteosarcoma Metastasis

Osteosarcoma is the most common primary sarcoma of bone among adolescents, often characterized by early lung metastasis resulting in high mortality. Recently, exosomes have been used in liquid biopsy for monitoring tumors. Herein, we used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to profile human plasma exosomes for the evaluation of osteosarcoma lung metastasis. Forty osteosarcoma patients with (n = 20) or without (n = 20) lung metastasis as well as 12 heathy controls were recruited. Exosomes were isolated from human plasma for MALDI-TOF MS analysis. Multivariate statistical analyses were performed on the MALDI-TOF mass spectra. It was demonstrated that the strategy can differentiate osteosarcomas from healthy controls and further discriminate osteosarcoma lung metastasis from non-lung metastasis. Seven exosomal potential protein biomarkers of osteosarcoma lung metastasis were identified. The proposed method has a great clinical application prospect in the diagnosis of osteosarcoma and monitoring of osteosarcoma lung metastasis.