P53,bcl-2,caspase-3 Cell Apoptosis And Apoptosis - Related Protein Expression In Human Thyroid Cancer And Hashimoto's Thyroiditis And Its Significance

OBJECTIVE: To investigate the expression and significance of apoptosis-related proteins in the pathogenesis in Hashimoto's thyroiditis (HT) and Thyroid Carcinoma.METHODS: Apoptotic level in thyroid tissue specimens from 14 patients with HT, 37 patients with TC and 5 patients with thyroid adenoma was evaluated by TUNEL & FCM method. Expression and distribution of p53, Bcl-2 and caspase-3 proteins in the specimens were investigated with immunohistochemical methods.RESULTS: A high percentage of apoptosis (28. 57% & 10. 61%) was observed by TUNEL method in thyroid follicles from HT specimens in comparison with that from TC specimens (5. 405% & 5. 70%, P=0. 041 & P=0. 002). Positive rates of p53, bcl-2 and caspase-3 in specimens of HT (7. 14%, 64. 29% & 85. 71%) while those in TC (18. 92%, 91. 89% & 56.76%). Only the positive rate of bcl-2 protein in specimens of HT (64.29%) was significantly lower than that in TC (91.89% P=0. 028). We investigate the expression of p53, bcl-2 and caspase-3 proteins in the HT and TC specimens. We found that bcl-2 is down regulated (rs,=-0.327 ; P=0.019), and caspase-3 is up regulated(rs=0.442; kP=0.001), in thyroid follicular cells from HT and TC specimens that exhibit apoptosis, but no significant correlations between p53 and apoptosis(rs=0.180; P=0. 207). It is suggesting that a suicidal mechanism, involving caspase-3 participates in the thyroid follicular cell destruction in HT and TC. Apoptosis and strongly positive immunostained thyroid cells with HT for caspase-3 were mainly distributed in follicles adjacent to lymphocytic infiltrates, whereas strongly positive...