Correlation between S100A4 and COX2 Overexpression and Invasiveness of Papillary Thyroid Carcinoma

Purpose: Tumor cell invasion is characteristic of malignant neoplasms. S100A4, a member of a family of small calcium binding proteins, and COX2, seem to have a role in promoting progression and invasion of many human cancers. The clinical stage of a papillary thyroid carcinoma (PTC) depends on age, tumor size, and extrathyroidal extension. Extrathyroidal extension is correlated with the invasiveness of a tumor. However, there are no reliable prediction markers for invasiveness. We evaluated S100A4 and COX2 expression in PTCs to determine if expression correlates with invasiveness, and if expression of S100A4 and COX2 are useful as prediction markers. Methods: The expression of S100A4 and COX2 were evaluated using immunohistochemical analysis in 35 PTC specimens. Results: More intense staining in cells that invaded the front portion rather than the central portion of a PTC was indicative of increased expression of S100A4 and COX2. Therefore, cases were analyzed for extent of staining in tumor cells that invaded the front portion of a PTC. High expression group (higher expression than average expression rate) of S100A4 and COX2 were significantly correlated with extrathyroidal extension (P = 0.0094 and P = 0.0433, respectively). However, no other clinicopathological factors including age, lymph node involvement, and multiplicity were related to expression of S100A4 and COX2, as determined in this study. Conclusion: Extrathyroidal extension of a PTC had an unfavorable effect on prognosis. S100A4 and COX2 expression were associated with extrathyroidal extension. These findings suggest that expression of S100A4 and COX2 could be prognostic markers for PTC. (J Korean Endocr Soc 23:186~192, 2008)