Highly Concordant Key Genetic Alterations in Primary Tumors and Matched Distant Metastases in Differentiated Thyroid Cancer.

Background: Distant metastases uncommonly occur in differentiated thyroid carcinoma (DTC), but they are a frequent cause of thyroid cancer–related death. Genomic alterations in metastatic tumors, and the relationship with their corresponding primary tumors in DTC, are poorly understood. The objective of this study was to investigate whether genetic alterations in primary tumors are concordant with distant metastases in DTC patients. Methods: Surgical samples from primary and matched distant metastatic tumor pairs from 17 DTC patients, and three additional unpaired metastatic tumors from two patients, were analyzed using targeted next-generation sequencing (Ion Torrent Ampliseq cancer panel) with a focus on known recurrent somatic mutations in thyroid cancer. Additionally, TERT promoter mutations were assessed by direct sequencing. Results: BRAF mutations were found in 8/10 patients with papillary thyroid carcinoma (PTC). A NRAS mutation was detected in one patient with follicular variant PTC. TERT promote...