system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Which of the following gene defect is associated with development of medullary carcinoma of thyroid?
assistant
The correct answer is  Activating point mutation in the RET proto oncogene plays impoant role in development of both familial and sporadiac medullary carcinoma of thyroid. The tumour tissue is firm,pale grey to tan and infiltrative. On microscopy,stroma shows acellular amyloid deposits which are derived from calcitonin polypeptides. Ref: Robbins and cotrans 9e pg 1099