Clinicopathological Implications of theBRAFV600EMutation in PTC with Concurrent Hashimoto Thyroiditis

Background and Objectives The relationship between Hashimoto thyroiditis (HT) and papillary thyroid cancer (PTC) is still controversial. Some studies suggested that molecular basis of the association between HT and PTC. BRAFV600E mutation is the most common genetic alteration founded in PTC. This study was to determine a role of BRAFV600E mutation in PTC with concurrent HT and their association with other clinicopathological factors. Materials and Methods We enrolled 452 patients who underwent thyroid surgery between 2009 and 2012 for classical PTC. The status of BRAFV600E mutation was evaluated by direct sequencing. HT was defined as presence of lymphocytic thyroiditis in pathology or positive serum anti-thyroid peroxidase antibody. Results Total 139 patients (30%) with PTC had coexistence HT. HT was significantly associated female (p=0.006), and younger age (p=0.045). BRAFV600E mutation was confirmed in 264 patients (58%). The frequency of BRAFV600E mutation was significantly lower in PTC with coexistence HT (48.2%) compared by PTC without HT (62.9%, p=0.004). However, there was no significant difference in clinicopathological feature of PTC according to the presence of HT in patients with BRAFV600E mutated PTC. BRAFV600E mutation was less frequent in PTC with coexistence HT. Conclusion These findings suggested that HT and BRAFV600E mutation might be independent factors in development and progression of PTC.