FLI1 and Ewing sarcoma: We denoted the copy numbers of EWS/FLI‐1 mRNA in the original 10 μL aliquoted A673 Ewing sarcoma EVs and Click Bead‐captured A673 EVs as EWS/FLI‐1 mRNA spiked‐EVs and EWS/FLI‐1 mRNA captured‐EVs, respectively.