This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc. (W.B.C), Subject name: Pathology
[{'content': 'The most important investigation in the given case to diagnose if the condition is a neoplasm? \nSelect and explain. \nA. JAK-2, B. EPO level, C. PaO2, D. Bone marrow aspiration and biopsy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) JAK-2The figure shows increased platelets in smear and increased megakaryocytes in bone marrow. To diagnose this as essential thrombocythemia (neoplasm); JAK-2 mutation analysis should be done.', 'role': 'assistant'}]