Relationship between protein expression of VEGF-C, MMP-2 and lymph node metastasis in papillary thyroid cancer

Papillary thyroid cancer (PTC) is a common malignancy and has a good prognosis after appropriate treatment. PTC cells spread mainly by lymph node metastasis (LNM), but the mechanism is not well understood. Expression of vascular endothelial growth factor C (VEGF-C) and matrix metalloproteinase 2 (MMP-2) protein was studied immunohistochemically from the archived specimens of 65 PTC patients who initially presented without LNM. In this retrospective study, the frequency of expression differed significantly between thyroid cancer tissue and adjacent normal follicular epithelium (VEGF-C 78.5% and 20.0%, respectively; MMP-2 81.5% and 36.7%, respectively). LNM developed in 35 of the patients during 5 - 15 years of follow-up, by the end of which the frequencies of expression of VEGF-C and MMP-2 protein expression were 91.4% and 94.3%, respectively. Both VEGF-C and MMP-2 protein expression were significantly more frequent in PTC with LNM than without LNM. VEGF-C and MMP-2 protein expression levels were significantly correlated with LNM and it is, therefore, feasible that VEGF-C and MMP-2 may be useful as tumour markers of PTC with cervical LNM.