Relationship between Trace Elements and Matrix Metalloproteinases 2 and 9 and their Tissue Inhibitors in Medullary Thyroid Carcinoma.

Medullary Thyroid Carcinoma (MTC) constitutes around 5% of all thyroid cancers. Trace elements assessment has emerged as a useful strategy in the diagnostics of MTC combined with Matrix Metalloproteinases (MMPs) and Tissue Inhibitors of Matrix Metalloproteinases (TIMPs) analysis. The aim of this study was to compare the presence and content of trace elements (i.e., Copper (Cu), Zinc (Zn), Iron (Fe), and Manganese (Mn)) in MTC with respect to control samples and their potential relationship with markers of MTC in tissues. The study included 26 patients who had undergone thyroidectomy, due to the diagnosis of MTC and 17 patients as control. We combined tumour pathology and staging, immunohistochemical analysis of calcitonin, MMPs, and TIMPs, with analytical biochemistry using Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) to determine the levels of trace elements. No differences by MTC type for MMPs and their TIPMs, although strong TIMP-1 and TIMP-2 immunohistochemical expression of MTC were unveiled. Additionally, Zn, Fe, and Mn tended to be decreased, and Cu to be increased in samples presenting MTC with respect to controls. Moreover, Zn was the unique trace element which seemed to be correlated with MMPs and TIMPs. Trace elements such as Zn, Fe, and Mn are decreased in tissues affected by MTC. In addition, Zn may be the trace element which saves more relationship with the proportion and intensity of MMPs, being considered altogether useful biomarkers of MTC. We therefore suggest the analysis of novel and traditional markers of MTC as a novel approach in this pathology.