MTC is characterized by the presence of high levels of calcitonin and the Zinc (Zn) peptidase–Matrix Metalloproteinases 2 and 9 (MMP-2 and MMP-9) and their Tissue Inhibitors of Matrix Metalloproteinases (TIMPs) [6, 7]. Here, MMP9 is linked to medullary thyroid gland carcinoma.