<prompt> Which of the following gene defect is associated with the development of medullary carcinoma of thyroid-RET Proto OncogeneFap gene.Rb geneBRCA 1 gene  <response>: Thyroid carcinomaThe major types of carcinoma and their relative frequency:- Papillary carcinoma 75 to 85 most common Medullary carcinoma 5 Follicular carcinoma 10 to 20 Anaplastic carcinoma 5Most thyroid carcinomas are derived from the follicular epithelium , except for medullary carcinoma which is derived from the parafallicular or C cells .Genetic factors in different thyroid carcinomaPapillary Tyrosine kinase receptors RET or NTR K1 RAS mutation BRAF oncogeneFollicular RAS oncogene NRAS, HRAS and KRAS PAX8- PPARr 1 translocationMedullary RET proto oncogene.Familial medullary cancers account for most inherited cases of thyroid cancer.Familial nonmedullary thyroid cancers papillary and follicular are very rare. 