CD9 and synovial sarcoma: In a comparison of MCT1+CD9+ EVs from patients with SS, ROC analysis revealed that MCT1+CD9+ levels were able to distinguish SS patients from pre- to post-operative status, with an AUC value of 0.84 (95% confidence interval [CI] = 0.65–1.00; p = 0.010) (Figure 3B).