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.