Role of molecular genetics in the preoperative diagnosis of thyroid tumors

Abstract

Incidence of thyroid tumors has been triplicated in United States and other countries during the last three decades. There is a 2.1-fold increase of thyroid carcinoma from 2001 to 2010 in Sri Lanka. Though there is a higher incidence of thyroid tumors, their malignancy rate is low. Ultra Sound Scanning (USS) and fine needle aspiration cytology (FNAC) are used as the main pre-operative diagnostic methods. However, histopathological examination of surgical sections is used as the gold standard in determining the malignancy of the thyroid nodules. In order to prevent unnecessary surgeries and the re-operations, effective pre-operative diagnosis is important. As most of other tumours, thyroid tumours too originated as a result of single or multiple genetic alterations or mutations of molecular markers like BRAF, RAS, RET/ PTC and TERT. These markers can be effectively used to determine the disease prognosis. The presence of any of these markers in the thyroid nodule represent a 100% positive predictive value and therefore it can be used for the clinical management of the patients. The use of molecular markers can significantly increase the diagnostic accuracy of thyroid malignancies. The combined use of molecular markers with the clinical findings and other pre surgical procedures including USS and FNAC can increase the diagnostic capability of the thyroid tumors. This can also be used for the individualized surgical approaches and post-surgical management of the patients.