Among the 28 Ewing sarcoma patients, the EWS/FLI‐1 and EWS/ERG rearrangements were compared between plasma samples and the respectively paired undecalcified formalin‐fixed paraffin‐embedded (FFPE) tissue samples of 12 Ewing sarcoma patients. This evidence concerns the gene EWSR1 and Ewing sarcoma.