This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
[{'content': 'A 74-year-old woman has metastatic bone disease on x-ray. Which of the following mediators is least likely to be involved? \nSelect and explain. \nA. interleukin-6 (IL-6), B. ectopic parathyroid hormone (PTH), C. tumor necrosis factor (TNF), D. interleukin-1 (IL-1)', 'role': 'user'}, {'content': 'Answer: B \nExplanation: A whole host of locally produced hormones and cytokines, as well as ectopically produced hormones, are implicated in local osteoclastic hypercalcemia. Parathormone-related protein is often elevated in malignant hypercalcemia (with or without bony metastases), but ectopic PTH production in malignancy is quite rare.', 'role': 'assistant'}]