Expression of caveolin-1, caveolin-2 and caveolin-3 in thyroid cancer and stroma.

OBJECTIVE To study the expression status of caveolin-1, caveolin-2 and caveolin-3 in the epithelial and stromal compartments of conventional papillary thyroid carcinoma (PTC), diffuse sclerosing variant of papillary carcinoma (DSVPC) and anaplastic carcinoma (AC). METHODS Tissue microarrays were constructed from 70 PTC, 41 DSVPC and 12 AC, and immunohistochemical stains were performed with caveolin-1, caveolin-2, caveolin-3, cytokeratin, vimentin and E-cadherin. The expression status of these markers in the epithelial and stromal cells was evaluated, and the results were correlated with the clinicopathologic variables. RESULTS Epithelial caveolin-3 expression was absent in the majority of PTC and DSPVC, and was significantly increased in AC (p < 0.001). The stromal expression of caveolin-1, caveolin-2 and caveolin-3 increased in frequency from PTC to DSVPC to AC, and was significantly increased in the stroma of AC (p < 0.001). Cytokeratin and E-cadherin were more frequently negative in AC compared to PTC (p = 0.003) and DSVPC (p < 0.001), while vimentin was more frequently expressed in AC compared to PTC and DSVPC (both p < 0.001). CONCLUSION Epithelial caveolin-3 expression is increased in AC compared to PTC and DSVPC, and this may be linked to the epithelial-mesenchymal transition process of AC. In addition, stromal caveolin-1, caveolin-2 and caveolin-3 expression was more frequent in AC compared to PTC and DSVPC, and the specific expression of caveolin-3 in the stroma of AC could suggest a possible role of myofibroblasts.