CD99 and Ewing sarcoma: Ewing sarcoma-derived tiny EVs may be biomarked by CD99, HINT1, and NGFR membrane proteins according to Samuel et al. They used these EV surface proteins to immuno-enrich Ewing sarcoma-associated tiny EVs and identify EWS-FLI1 and EWS-ERG fusion transcripts in plasma from localized and metastatic patients [88].