Activation of nuclear factor-kappa B contributes to growth and aggressiveness of papillary thyroid carcinoma

Nuclear factor-kappa B (NF-kappa B) is involved in proliferation, angiogenesis, and metastasis in various malignancies; however, the role of NF-kappa B in papillary thyroid carcinoma (PTC) has not been fully elucidated. The purpose of this study was to elucidate the role and clinicopathological significance of the NF-kappa B signaling pathway in PTC. We investigated NF-kappa B RelA expression in 122 patients with conventional PTC by immunohistochemistry, and evaluated the correlation between RelA expression and clinicopathological parameters, including BRAF(V600E) mutation. Nuclear expression of NF-kappa B RelA, regardless of cytoplasmic expression, was identified in 91 of 122 PTCs (74.6%), and was more frequent in PTCs larger than 1 cm (overt PTC) (P=0.001). There were significant differences in clinicopathological parameters, such as extrathyroidal extension (P=0.031), nodal metastasis (P=0.021) and BRAF(V600E) mutation (P=0.039), between NF-kappa B-positive and negative PTCs. Proliferation index was strongly associated with NF-kappa B activation (P=0.045) but not with BRAF(V600E) mutation (P=0.141). Taken together, our results suggest that NF-kappa B RelA activation contributes, at least in part, to tumor growth and aggressiveness of PTC after tumor transformation. The expression pattern of NF-kappa B may serve as a prognostic marker and a potential therapeutic target. (C) 2013 Elsevier GmbH. All rights reserved.