Preoperative plasma concentrations of vascular endothelial growth factor and matrix metalloproteinase 9 are associated with stage progression in papillary thyroid cancer

Abstract

Objective: Vascular endothelial growth factor (VEGF), a potent angiogenic peptide, and matrix metalloproteinase 9 (MMP-9), a proteolytic enzyme, are found to be abundantly expressed in several types of cancer and correlate with tumour progression. In this study, we investigated the relationship between preoperative plasma VEGF, MMP-9 levels and disease stages in papillary thyroid cancer.

Design: Plasma samples were consecutively collected from 30 patients with papillary thyroid cancer preoperatively (seven males and 23 females with a mean age of 45 +/- 16 years) and control plasmas obtained from 30 patients with benign goitre (seven males and 23 females with a mean age of 44 +/- 18 years) and 23 healthy persons (four males and 19 females with a mean age 44 +/- 15 years). Plasma VEGF and MMP-9 concentrations were determined by enzyme-linked immunosorbent assay. Cancer progression was staged by the TNM classification of the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (UICC).

Results: In thyroid cancer patients, the plasma VEGF and MMP-9 values were higher than those in controls (51.8 +/- 11.5 ng/l vs. 27.0 +/- 0.8 ng/l; 72.3 +/- 23.3 micro g/l vs. 22.1 +/- 3.0 micro g/l, respectively; P < 0.05), and those in benign goitre (51.8 +/- 11.5 ng/l vs. 39.7 +/- 8.8 ng/l; 72.3 +/- 23.3 micro g/l vs. 23.0 +/- 2.2 micro g/l, respectively; P < 0.05). But, there was no difference of plasma VEGF and MMP-9 between patients with goitre and normal subjects. A comparison of VEGF and MMP-9 levels in patients at each cancer stage and in patients with benign nodule found that plasma VEGF and MMP-9 values in TNM stages III and IV, but not stage I or II, were significantly elevated (P < 0.05). When cancer patients were grouped according to clinopathological features, the plasma VEGF and MMP-9 concentrations were both significantly elevated in patients with large tumour size (P < 0.01), lymph node involvement (P < 0.01), extrathyroidal invasion (P < 0.05), distant metastasis (P < 0.05) or advanced stages (P < 0.01).

Conclusion: Our study demonstrated that circulating VEGF and MMP-9 levels correlated with progression of papillary thyroid cancer, suggesting plasma VEGF and MMP-9 may serve as preoperative adjuvant markers for assessing disease activity in papillary thyroid cancer. However, they should not be used as a diagnostic tool for differentiating malignant from benign thyroid disorders.