SMARCB1 expression is a novel diagnostic and prognostic biomarker for osteosarcoma

Background: Although weak SMARCB1 expression is a known diagnostic and prognostic biomarker in several malignancies, its expression and clinical significance in osteosarcoma remain unknown. The aim of this study was to investigate SMARCB1 expression in osteosarcoma and its clinical significance with respect to chemosensitivity and prognosis. Methods: We obtained 114 specimens from 70 osteosarcoma patients to construct a tissue microarray (TMA) and assess SMARCB1 protein expression via immunohistochemistry. The mRNA expression of SMARCB1 was in silico analyzed using open-access RNA sequencing (RNA-Seq) and clinicopathological data provided by the Therapeutically Applicable Research to Generate Effective Treatments on Osteosarcoma (TARGET-OS) project. The correlations between SMARCB1 expression and clinical features were statistically analyzed. Results: Weak SMARCB1 expression occurred in 70% of the osteosarcoma patient specimens in the tissue microarray, and significantly correlated with poor neoadjuvant response as well as shorter overall and progression-free survival. In addition, mRNA in silico analysis confirmed SMARCB1 expression correlates with chemotherapeutic response and prognosis in osteosarcoma patients. Conclusion: To our knowledge, this study is the first to analyze SMARCB1 expression in osteosarcoma. SMARCB1 may serve as a novel diagnostic and prognostic biomarker in osteosarcoma.