A 23-year-old man is being evaluated for the new development of a nodule in his neck. Physical examination finds a 3.5-cm thyroid nodule. The lesion is removed surgically, and histologic sections reveal groups of poorly differentiated tumors cells within a stroma with large areas of amyloid. This familial form of this type of malignancy is associated with abnormalities of which of the following protooncogenes

Medullary carcinoma of the thyroid is a malignant neoplasm that originates from the parafollicular C cells of the thyroid. These cells normally secrete calcitonin. Stromal aggregates of procalcitonin are seen histologically within these tumors as amyloid, which is a type of protein that demonstrates an "apple-green" birefringence with a special Congo red stain. Although most cases of medullary thyroid carcinomas are sporadic, the familial form is associated with abnormalities of the ret protooncogene. This type of malignancy also is seen in multiple endocrine neoplasia types 2 and 3. Ref:- Harsha Mohan textbook of Pathology