Clinical Significance of p53, Ki-67 and Galectin-3 Expressions in Papillary Thyroid Carcinoma

ABSTRACT

PURPOSE: There are few molecular markers useful in practice for predicting prognosis of papillary thyroid carcinoma (PTC) despite numerous basic researches. The objective of this study was to evaluate the prognostic values of several candidate markers of PTC (p53, Ki-67 and galectin-3) using immunohistochemistry (IHC), one of the most practical methods. METHODS: IHC for p53, Ki-67 and galectin-3 were performed on formalin-fixed paraffin-embedded tissues of 160 PTC specimens using monoclonal antibodies. The associations of the expressions of these markers with multiple clinicopathologic prognostic factors were assessed. RESULTS: The overexpresion rates of p53, Ki-67 and galectin-3 were 48.8%, 64.3% and 97.8%, respectively. Overexpression of p53 protein was positively associated with extrathyroidal extension (P<0.001). In addition, p53 immunoreactivity was more prevalent among Ki-67 overexpressed specimens (P<0.001). Ki-67 immunoreactivity was positively correlated with tumor size (P<0.05), which became more distinct when accompanied with p53 overexpression (P<0.01). In contrast, no relationship between galectin-3 immunoreactivity and clinical prognostic factors was found. CONCLUSION: Our results suggest that overexpression of p53 protein and Ki-67 in papillary thyroid carcinoma is associated with tumor progression and that IHC for these proteins could be useful for predicting prognosis of patients with PTC.