ENG and neoplasm: Flow cytometry results showed the expression of the synovial fluid-derived mesenchymal stem cell surface markers CD29, CD44,CD73, CD90, CD105, and CD147 but not the neural stem cell surface marker CD24 or the hematopoietic stem cell surface markers CD34 and CD45, and the cells did not express the interstitial tumor cell markers CD117 and malignant epithelial CD146.