CXC Chemokine receptor type 4 (CXCR4) is commonly considered a potential marker for cancer stem cells (CSCs). Dedifferentiated-type chordoma (DTC) cells derived from a patient with recurrent chordoma exhibit high CXCR4 expression and demonstrate increased resistance to chemotherapeutic drugs and ionizing radiation (IR) compared to the conventional-type chordoma cell line, U-CH1. However, the precise role of CXCR4 in the stemness and IR resistance of DTC remains unclear. Therefore, this study aims to elucidate the correlation between the expression of CXCR4 and stemness and radioresistance in chordoma. DTC cells expressing CXCR4 (CXCR4