This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
CD-99 is marker of : 
Select and explain. 
A. Ewings sarcoma, B. SLL, C. Dermatofibrosarcoma, D. Malignant fibroma histiocytic tumor
A: Ewings sarcoma
Answer: A: Ewings sarcoma 
Explanation: CD-99 can be used as a tumor  marker for ewings sarcoma.