This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc., Subject name: Pathology
[{'content': "Ewing's sarcoma is associated with \nSelect and explain. \nA. CD-56, B. CD-38, C. CD-117, D. CD-139", 'role': 'user'}, {'content': "Answer: A \nExplanation: (A) CD-56 # Tumor cells in Ewing's sarcoma show diffuse membrane positivity for CD-56. Tumor cells are also positive for neuron-specific enolase.# Ewing's sarcoma (or Endothelial sarcoma of bone):> It is a highly malignant tumour, occurring between the age of 10-20 years.> Multicentric in origin.> Cytogenetic abnormalities associated with Ewing's sarcoma is the reciprocal translocation of the long arm of chromosomes 11 and 22> It arise in the diaphysis of long bone> Subperiosteal bone formation> Histopathologically -- Pseudo rosette formation.> The tumour grow fast and metastasises through the blood stream to the lungs and to other bones.# Clinical Features -- Pain, swelling and Fever, so it may be confused with osteomyelitis> X-Ray show - Onion peel appearance> Treatment - Highly radio sensitive tumour, so Radiotherapy is highly effective for control of the local tumour and chemotherapy for control of the metastasis.", 'role': 'assistant'}]