Abstract
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.