Significance of Expression of Cell Cycle Related Proteins and Apoptosis Related Proteins in Follicular Adenoma and Follicular Carcinoma of Thyroid

ABSTRACT

PURPOSE: To explore the role of cell cycle regulators and apoptosis regulators in carcinogenesis of thyroid, the expression of cell cycle related proteins (cyclin D1, Ki-67) and apoptosis related proteins (survivin, caspase 3, bcl-2, p53) were investigated in follicular adenoma and follicular carcinoma of thyroid. METHODS: The following formalin-fixed paraffin embedded surgical specimens were immunohistochemically stained by avidin-biotin complex method for cyclin D1, Ki-67, survivin, caspase 3, bcl-2, p53; 15 cases of follicular adenoma (FA), 31 cases of minimally invasive follicular carcinoma (MIFC) and 12 cases of widely invasive follicular carcinoma (WIFC). RESULTS: The overexpression of six gene products in follicular neoplasms of thyroid was noted in varying frequency. Among them, increased Ki-67, caspase 3 index and overexpression of bcl-2 were noted in statistically significant, widely invasive follicular carcinoma than that of follicular adenoma and minimally invasive follicular carcinoma. CONCLUSION: These results suggest that the overexpression of Ki-67, caspase 3, bcl-2 appear to play an important role during follicular carcinogenesis of thyroid. In addition, the overexpression of these proteins is related to the differentiation of MIFC and WIFC. However, further molecular genetic studies are required to determine the interrelationships between the expression of cell cycle related proteins and apoptosis related proteins.