This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
[{'content': 'All of the following immunohistochemical markers are positive in the neoplatic cells of granulocytic sarcoma, except - \nSelect and explain. \nA. CD45 RO, B. CD 43, C. Myeloperoxidase, D. Lysozyme', 'role': 'user'}, {'content': "Answer: A \nExplanation: Diagnostic IHC markers BrdU: used to identify replicating cells. ... Cytokeratins: used for identification of carcinomas but may also be expressed in some sarcomas. CD15 and CD30 : used for Hodgkin's disease. Alpha fetoprotein: for yolk sac tumors and hepatocellular carcinoma. Refer robbins 9/e", 'role': 'assistant'}]