Ewing Sarcoma Cells Secrete <i>EWS/Fli-1</i> Fusion mRNA via Microvesicles

<div><p>Tumours defined as Ewing sarcoma (ES) constitute a group of highly malignant neoplasms that most often affect children and young adults in the first 2 decades of life. The <i>EWS/Fli-1</i> fusion gene, a product of the translocation t(11;22) (q24; 12), is detected in 95% of ES patients. Recently, it was validated that cells emit a heterogeneous mixture of vesicular, organelle-like structures (microvesicles, MVs) into their surroundings including blood and body fluids, and that these MVs contain a selected set of tumor-related proteins and high levels of mRNAs and miRNAs. In this present study, we detected the Ewing sarcoma-specific <i>EWS/Fli-1</i> mRNA in MVs from the culture medium of ES cell lines carrying t(11;22) (q24; 12). Also, we detected this fusion gene in approximately 40% of the blood samples from mice inoculated with xenografts of TC135 or A673 cells. These findings indicate the <i>EWS/Fli-1</i> mRNA in MVs might be a new non-invasive diagnostic marker for specific cases of Ewing sarcoma.</p>