DCX and CRABP2 are candidate genes for differential diagnosis between pre‐chemotherapy embryonic and alveolar rhabdomyosarcoma in pediatric patients

IMPORTANCE: Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. More than 90% of cases are classified as embryonic RMS (ERMS) or alveolar RMS (ARMS). ERMS has a worse prognosis than ARMS. Early differential diagnosis is of paramount importance for optimization of treatment. OBJECTIVE: To identify genes that are differentially expressed between ARMS and ERMS, which can be used for accurate rhabdomyosarcoma classification. METHODS: Three Gene Expression Omnibus datasets composed of ARMS and ERMS samples were screened and 35 differentially expressed genes (DEGs) were identified. Receiver operating characteristic curve analysis and area under the curve analysis was performed for these 35 DEGs and seven candidate genes with the best differential expression scores between ARMS and ERMS were determined. The expression of these seven candidate genes was validated by immunohistochemical analysis of pre‐chemotherapy ARMS and ERMS specimens. RESULTS: The levels of DCX and CRABP2 were confirmed to be remarkably different between paraffin‐embedded ARMS and ERMS tissues, while EGFR abundance was only marginally different between these two RMS subtypes. INTERPRETATION: DCX and CRABP2 are potential biomarkers for distinguishing ARMS from ERMS in pre‐chemotherapy pediatric patients.