Enhanced activation of matrix metalloproteinase-9 correlates with the degree of papillary thyroid carcinoma infiltration.

AIM: To determine whether matrix metalloproteinase-9 (MMP-9) may be a useful adjunctive tool for predicting unfavorable biological behavior of papillary thyroid carcinoma (PTC) by evaluating the expression profile and proteolytic activity of MMP-9 in PTC by different techniques and correlating the findings with clinicopathological prognostic factors. METHODS: Immunohistochemical localization of MMP-9 was analyzed with antibodies specific for either total or active MMP-9. Activation ratios of MMP-9 were calculated by quantifying gel zymography bands. Enzymatic activity of MMP-9 was localized by in situ zymography after inhibiting MMP-2 activity. RESULTS: Immunostaining of total and active MMP-9 was observed in tumor tissue and occasionally in non-neoplastic epithelium. Only active MMP-9 was significantly associated with extrathyroid invasion, lymph-node metastasis, and the degree of tumor infiltration (P<0.001, P=0.004, and P<0.001, respectively). Gelatin zymography revealed a correlation between the MMP-9 activation ratio and nodal involvement, extrathyroid invasion, and the degree of tumor infiltration. In situ zymography showed that gelatinases exerted their activity in tumor parenchymal and stromal cells. Moreover, after application of MMP-2 inhibitor, the remaining gelatinase activity, corresponding to MMP-9, was highest in cancers with the most advanced degree of tumor infiltration. CONCLUSIONS: This is the first report suggesting that the evaluation of active MMP-9 by immunohistochemistry and determination of its activation ratio by gelatin zymography may be a useful adjunct to the known clinicopathological factors in predicting tumor behavior. Most important, in situ zimography with an MMP-2 inhibitor for the first time demonstrated a strong impact of MMP-9 activity on the degree of tumor infiltration during PTC progression.

Caveolin-1 expression in papillary thyroid carcinoma: correlation with clinicopathological parameters and BRAF mutation status.

OBJECTIVE: We aimed to investigate the role of caveolin-1 in papillary thyroid carcinoma pathogenesis. STUDY DESIGN: Case series with chart review. SETTING: Institute for the Application of Nuclear Energy. SUBJECTS AND METHODS: We evaluated the expression of caveolin-1 in papillary thyroid carcinoma (PTC) by Western blot (WB) and compared the findings with immunohistochemical (IHC) expression of both epithelial and stromal caveolin-1 on the corresponding histological specimens. The results were related to clinicopathological features and BRAF mutation status. RESULTS: Caveolin-1 expression was found in malignant thyroid epithelium and more abundantly in tumor stroma but varied in both compartments within and between PTC subtypes. Caveolin-1 expression in the epithelium was more intense in classical PTC than in the other histological types. On the contrary, stromal caveolin-1 expression was stronger in the follicular, solid, and trabecular PTC variants than in classical PTC. Trends for down-regulation of caveolin-1 expression in epithelium and up-regulation in stroma from the classical via follicular to the solid variant were observed. The relation of WB and IHC results with clinicopathological parameters showed lower caveolin-1 tissue content in BRAF mutated tumors (P < .05), a positive correlation of epithelial caveolin-1 expression with lymph node metastasis (P < .05), and a negative association of stromal caveolin-1 expression with the degree of neoplastic infiltration and BRAF status. CONCLUSION: Altered expression of caveolin-1 in the thyroid epithelial and stromal compartments may be involved in the pathogenesis of PTC. The potential clinical significance of caveolin-1 expression, as well as its relation to BRAF mutation status, deserves further investigation.

Evaluation of survivin expression and its prognostic value in papillary thyroid carcinoma.

Overexpression of survivin, an inhibitor of apoptosis protein, has been found in a variety of human cancers, and is associated with tumor aggressiveness. In this study, we analyzed the expression of survivin in papillary thyroid carcinoma (PTC) and evaluated its clinical significance for predicting an aggressive course of disease at the time of diagnosis. Survivin expression was determined by immunohistochemistry in 104 tissue specimens of PTC, confirmed by Western blot and correlated with clinicopathological parameters. Of the tumors examined, 74 (71.15%) showed high cytoplasmic survivin expression. There was no association between high survivin expression and age, gender or tumor size. On the other hand, it was closely correlated with the presence of lymph node metastasis (P=0.009), and there was a tendency for correlation with extrathyroidal invasion (P=0.062). The high risk PTC group (TNM stage III-IV) was associated with high levels of survivin (P=0.027). These results indicate that survivin is an unfavorable molecule for PTC prognosis, and that its high expression may indicate a subset of PTC patients with a more aggressive disease course. Evaluation of its expression in fine needle aspiration samples could be a useful tool for the identification of those PTC patients who require more extensive surgery, careful follow-up and therapeutic strategy.

Caveolin-1 expression in thyroid neoplasia spectrum: comparison of two commercial antibodies.

We evaluated caveolin-1 expression in the human thyroid neoplasia spectrum with the aim of examining differences in expression as detected by two anti-caveolin-1 antibodies, and secondly, to investigate the association of caveolin-1 expression levels with aggressive papillary thyroid carcinoma (PTC). Immunohistochemical staining using sc894 or AV09019 antibodies revealed that caveolin-1 was generally overexpressed in the PTC group as a whole (classical and follicular variant) when compared to peritumoral tissue (PT), while it was not detected in about half of follicular thyroid carcinoma (FTC) and majority of follicular adenomas (FTA). Caveolin-1 expression decreased in the following order: clPTC, fvPTC, FTC, PT and FTA. The diagnostic accuracy of AV09019 was better than that of sc894 for discriminating: FTA from FTC, FTA or FTC from the follicular variant of PTC, total PTC from nonmalignant tissue, and malignant tumors from nonmalignant tissue. Spearman's analysis revealed positive correlations of caveolin-1 expression and extrathyroidal invasion (p< 0.05) in PTC for both antibodies. Additionally, AV09019 antibody correlated caveolin-1 upregulation with pathological T status. To conclude, as an immunohistochemical marker AV09019 antibody performed better than sc894 in distinguishing certain histotypes of thyroid tumors. In addition, increased expression of caveolin-1 may be considered as an indicator of papillary carcinoma progression.

Expression of matrix metalloproteinase-2 and its tissue inhibitor-2 in fetal and neoplastic thyroid tissue and their significance as diagnostic and prognostic markers in papillary carcinoma.

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) have roles in physiological and pathological processes. We evaluated immunohistochemical expression of MMP-2 and TIMP-2 in paraffin sections of 12 human fetal thyroids at mid-term gestation and 79 thyroid tumors of follicular origin. Besides evaluating expression of these proteins during fetal development and neoplastic transformation, we determined whether expression of MMP-2 and TIMP-2 may help to differentiate papillary thyroid carcinoma (PTC) from follicular thyroid adenoma (FTA) and/or peritumoral tissue (PT). We also investigated their relationship with prognostically important clinicopathological parameters of PTC. Immunoreactive MMP-2 and TIMP-2 were found in all fetal thyroid tissues examined. Tumor tissues contained variable amounts of MMP-2 and TIMP-2, with overexpression of these proteins in PTC compared to FTA and PT tissue. According to the statistical analysis, MMP-2 distinguished follicular variant of PTC from FTA and overall PTC from total nonmalignant lesions. In PTC, high MMP-2 expression correlated with lymph node metastasis (P=0.022), while high TIMP-2 expression was positively correlated with tumor size (P=0.049) and extrathyroid invasion (P=0.017). Overall, these results indicate a role for MMP-2 and TIMP-2 in both thyroid development and malignant transformation and suggest that positive immunohistochemistry for MMP-2 and TIMP-2 might support diagnosis of PTC and predict unfavorable biological behavior.

Serum Cyfra 21.1 and galectin-3 protein levels in relation to immunohistochemical cytokeratin 19 and galectin-3 expression in patients with thyroid tumors.

PURPOSE: The aim of this study was to assess the clinical utility of circulating preoperative Cyfra 21.1 [soluble fragment of cytokeratin (CK) 19] and galectin-3 (gal-3) in patients with thyroid tumors, to compare their serum values with tissue expression and to analyze the prognostic significance of these markers in relation to the clinical status of postsurgical differentiated thyroid carcinoma (DTC) patients. PATIENTS: Concentrations of Cyfra 21.1 and gal-3 were evaluated by immunoassays in sera of 9 healthy subjects, 97 preoperative patients with diverse thyroid tumors (10 FTA, 63 PTC, 11 FTC, 5 PDTC, 4 ATC, 4 LNM) and 25 postoperative DTC patients (14 remissions and 11 metastases). RESULTS: Low Cyfra 21.1 values were found in all subgroups, but with a tendency toward higher values in poorly differentiated DTC patients. Compared to the control (0.23 ng/mL), serum levels of gal-3 were significantly elevated in patients with thyroid tumors but with overlapping between adenoma (4.16 ng/mL) and carcinoma (3.85, 4.37, 4.64, 6.07 ng/mL for PTC, PDTC, ATC and LNM, respectively). The tissue expression of CK19 and gal-3 was immunohistochemically determined on 45 matched paraffin-embedded sections. Most thyroid carcinomas showed positive CK19 (27/35) and gal-3 immunostaining (31/35), while adenomas were mostly immunonegative (8/10 and 7/10, respectively). However, there was no significant correlation between their serum and tissue levels. Clinical status of postoperative DTC patients had no influence on serum concentrations of the tested markers. CONCLUSIONS: While CK19 and gal-3 are accurate as tissue markers, their serum levels could not be used as reliable markers for identification of thyroid malignancy or in thyroid cancer follow-up. On the other hand, a tendency toward higher serum levels of Cyfra 21.1 in the small number of PDTC patients examined adds weight to previous reports postulating a role for cytokeratins in predicting a high degree of malignancy.