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.