Der Schilddrüsenknoten: molekulargenetische und zytogenetische Aspekte

Formation of thyroid nodules is frequent in areas with iodine deficiency. The sequence leading from iodine deficiency to formation of nodules is only partially understood. However, knowledge about a number of molecular aberrations in different types of nodules has considerably grown. The majority of benign and nearly all malignant thyroid nodules are of monoclonal origin and therefore represent true tumors. Toxic adenoma is frequently caused by mutations of the TSH receptor. Euthyroid multinodular goiter may be associated with changes on chromosomes 2 and 14. Papillary thyroid cancer is frequently caused by fusion genes resulting in activation of tyrosine kinases. Follicular neoplasms often carry ras mutations. Anaplastic thyroid cancer is closely associated with p53 mutations. As yet, there are no direct therapeutic consequences of these discoveries. However, the detailed molecular knowledge offers the perspective of a highly sensitive and specific pre-operative diagnosis of thyroid nodules.