<prompt> RET proto-oncogene is associated with which carcinoma?Hepatocellular CarcinomaMENTesticular carcinomaBreast carcinoma  <response>: Ans. is b i.e., MEN RET is a growth factor receptor receptor tyrosine kinase. RET protein is a receptor for glial cell lined derived neurotrophic factor. RET is normally expressed in parafollicular C cells of thyroid, adrenal medulla and parathyroid cell precursons. Point mutation in RET protooncogenes is associated with MEN-2A, MEN-2B, medullary thyroid carcinoma and Hirschsprung disease. 