Identification and Experimental Validation of Tumor Antigens and Hypoxia Subtypes of Osteosarcoma for Potential mRNA Vaccine Development.

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents. The aim of this study was to explore the possibility of OS hypoxia subtype for anti-OS mRNA vaccine development and select suitable patients for precision therapy. We comprehensively explored hypoxia-related genes (HRGs) as potential sources of tumor neoantigens in OS patients. Gene set enrichment analysis algorithm and consensus clustering analysis were used to determine immune subtypes and evaluate tumor microenvironment. Estimation of stromal and immune cells in malignant tumour tissues using expression data algorithm was used to assess tumour immune activity. The OS hypoxia landscape was visualized using dimensionality reduction analysis based on the DDRTree algorithm. Assessment of clinical samples and molecular experiments were performed to verify the determined tumor antigens. Four overexpressed and mutated tumor antigens associated with prognosis and infiltration of antigen-presenting cells were identified and verified by clinical samples and molecular experiments. Furthermore, OS patients were stratified into two OS hypoxia subtypes. Interestingly, patients with the OS hypoxia subtype 1 tumor had a superior survival than those with the OS hypoxia subtype 2 tumor. Distinct expressions of immune checkpoint proteins (ICPs) and immunogenic cell death (ICD) modulators were observed in different immune subtype tumors. Finally, the immune landscape of OS showed a high degree of heterogeneity between individual patients. This study identified potential antigens for the anti-OS mRNA vaccine as well as different OS hypoxia subtypes, guiding more effective immunotherapeutic strategies and selecting appropriate patients for tumor vaccine therapy.