Abstract
Background: Osteosarcoma, a highly malignant bone tumor prevalent in children and adolescents, continues to have poor long-term survival rates, particularly in metastatic cases. While histone acetylation dysregulation has been implicated in cancer progression, the role of histone acetylation modification-related proteins (HAMRPs) in osteosarcoma immune infiltration and prognosis remains unclear. Methods: The expression patterns, prognostic implications, and clinical correlations of HAMRPs in osteosarcoma were analyzed using the TARGET, GEO, TISCH, and HPA databases. The effectiveness of HAMRPs in predicting the immune landscape of osteosarcoma was confirmed using CIBERSORT, ssGSEA, and ESTIMATE algorithms. The study employed GSEA analysis, wound healing assay, Transwell, and western blot to explore the role and regulatory mechanism of the key gene ASH1L in osteosarcoma progression. Results: Two distinct histone acetylation modification patterns were identified, showing significant differences in survival, clinical features, and immune landscape. Comprehensive clinical correlation analysis and Kaplan-Meier analysis of all HAMRPs used for two subtypes revealed that higher ASH1L expression was found in metastatic osteosarcoma cases and indicated poorer survival outcomes. In vitro experiments confirmed that ASH1L promoted osteosarcoma metastasis and epithelial-mesenchymal transition via the AKT/mTOR pathway. Additionally, an ASH1L-derived risk model was developed to aid personalized clinical decisions. Conclusions: This study elucidates the prognostic and immunological significance of HAMRPs and highlights ASH1L as a novel aggressive marker in osteosarcoma.