Potential relationship between Hashimoto's thyroiditis and BRAF(V600E) mutation status in papillary thyroid cancer.

BACKGROUND The purpose of this study was to evaluate the potential relationship between Hashimoto's thyroiditis and BRAF(V600E) mutation status in patients with papillary thyroid carcinoma (PTC). METHODS A total of 619 patients with PTC who underwent total thyroidectomy with lymph node dissection were enrolled in this study. Univariable and multivariate analyses were used. RESULTS Hashimoto's thyroiditis was present in 35.9% (222 of 619) of PTCs. Multivariate logistic regressions showed that BRAF(V600E) mutation, sex, extrathyroidal extension, and lymph node metastasis were independent factors for Hashimoto's thyroiditis. Female sex, more frequent extrathyroidal extension, and a higher incidence of lymph node metastasis were significantly associated with PTCs accompanied by BRAF(V600E) mutation without Hashimoto's thyroiditis compared with PTCs accompanied by BRAF(V600E) mutation with Hashimoto's thyroiditis. CONCLUSION Hashimoto's thyroiditis was negatively associated with BRAF(V600E) mutation, extrathyroidal extension, and lymph node metastasis. In addition, Hashimoto's thyroiditis was related to less lymph node metastasis and extrathyroidal extension in PTCs with BRAF(V600E) mutation. Therefore, Hashimoto's thyroiditis is a potentially protective factor in PTC. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1019-E1025, 2016.