The Expression And Significance Of Signal Transducer And Activator Of Transcription STAT3, STAT5 In Differentiated Thyroid Carcinama

Obective: To investigate the expression of STAT3,STAT5 (signal transducer and activator of transcription, STAT) and their relationship with clininopathological factors and in differentiated thyroid carcinoma, so as to study the role of STAT3,STAT5 in thyroid carcinoma.Methods: 42 differentiated thyroid carcinomas (DTC), 30 thyroid adenomas and 15 normal thyroid tissues adjacent to adenomas were investigated. There are 38 papillary thyroid carcinoma(PTC) and 4 follicular thyroid carcinoma Among 42DTC, which include 7 male and 35 female. within 17-77age group. the mean age was 44.23±14.69y, size of the tumor less than 4cm was 25cases and 17cases larger than 4cm. 12cases was infiltrated and the other 30 cases were not. 15cases had the lymph metastasis. 27 cases had no lymph metastasis. 5 male and 25 female for thyroid adenomas, the age group was whitin 18-76y,mean age was 48.68±13.65y. The protein expression of STAT3, STAT5, p53, p21 was detected by immunohistochemical staining (SABC) method and analyzed by computer digitizing system.Results: DTC , thyroid adenoma and normal thyroid tissue have the positive expression of Stat-3 and Stat-5, which was located within the cytoplasm. The positive expression rate of STAT3 and STAT5 were 54.8% (23/42), 66.7% (28/42) in thyroid carcinoma specimens and were significantly increased compared with thyroid adenoma and normal thyroid tissue respectively (P<0.05). STAT5 was significantly higher than STAT3. The positive expression of P53 and P21 were located in the cellular nucleus and were brown colored. The positive expression rate of p53 in thyroid carcinoma was 23.8%(10/42), while no expression in thyroid adenoma and normal thyroid tissue (P<0.05). The expression of p21 in thyroid carcinoma14.3%(6/42) was significantly decreased compared to thyroid adenoma 46.7%(14/30) and normal thyroid tissue33.3%(5/15), (P<0.05). There is no significant different expression of p21 between thyroid adenoma 46.7%(14/30) and normal thyroid tissue33.3%(5/15). It showed that both STAT3 and STAT5 in papillary thyroid carcinoma were higher than in follicular thyroid carcinomas (P<0.05). But they were not related to other clinicopathological factors. The expression of Stat5 was significantly increased compared with Stat3 and was correlate to Stat3 positively (r=0.78). The Stat3 were positively correlate to p53 (r=0.77) and negatively related to p21(r=-0.87). The Stat5 were positively correlate to p53 (r=0.72) and negatively related to p21(r=-0.67). Conclusions: The data suggest the abnormal expression of STAT3 and STAT5 may play an important role in the carcinogenesis of thyroid carcinoma. STAT3 and STAT5 may become two pathological indexes for diagnosis and differentiation of thyroid carcinoma, but they are not used to assess the biological behaviors of thyroid carcinoma. Perhaps the abnormal expression of Stat3, Stat5 may be caused by mutation of p53 and deactivation of p21.