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: Pathology
[{'content': 'Gene involved in medullary carcinoma thyroid is \nSelect and explain. \nA. Ret Proto Oncogene, B. Fap gene, C. Rb gene, D. BRCA 1 gene', 'role': 'user'}, {'content': "Answer: A \nExplanation: The RET proto-oncogene encodes a receptor tyrosine kinase for members of the glial cell line-derived neurotrophic factor (GDNF) family of extracellular signalling molecules.RET loss of function mutations are associated with the development of Hirschsprung's disease, while gain of function mutations are associated with the development of various types of human cancer, including medullary thyroid carcinoma, multiple endocrine neoplasiastype 2A and 2B, pheochromocytoma and parathyroid hyperplasia", 'role': 'assistant'}]