Differential Protein Expression of Lymph Node Metastases of Papillary Thyroid Carcinoma Harboring the BRAF Mutation

Abstract

Background: The prognostic role of the T1799A BRAF mutation is controversial. We investigated the protein expression in papillary thyroid carcinoma (PTCs) samples harboring the specific mutation using proteomic tools. Materials and Methods: We performed two-dimensional gel electrophoresis to identify differential protein expression regarding lymph node metastasis (LNM). Proteins were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Immunohistochemical staining was performed for 38 PTCs harboring the mutation. We validated the association between these proteins and clinicopathological factors in a test set of 121 PTCs. Results: The expression of vimentin was increased in PTCs with LNM, but the one for HSP60, SOD2 and PEBP1 was increased in samples without LNM. HSP60 protein was up-regulated in PTCs without LNM (84.2% vs. 36.8%. p=0.003) and in PTCs without LNM harboring the mutation (58% vs. 41.8%. p=0.003) in the test set as shown by immunohistochemical staining. Conclusion: HSP60 protein expression may inhibit LNM in PTCs harboring the BRAF mutation and may be a useful prognostic marker.