Ki-67 Is Highly Expressed in the Medullary thyroid Carcinoma and Indicates Poor Prognosis
【摘要】：Objective: To study the expression of Ki-67 in medullary thyroid tumor tissue as well as the relationship between the Ki-67 expression and the malignancies of medullary thyroid cancer Methods: Tumor tissue from 69 cases of medullary thyroid cancer was collected in accordance with the Declaration of Helsinki. Ki-67 expression in the medullary thyroid tumor tissue was evaluated by Immunohistochemical, quantitative PCR(qPCR) and western blot. The correlation between the Ki-67 expression and the prognosis of medullary thyroid cancer was evaluated by Cox regression model. In addition, TT cell were transfected with two siRNA targeted to Ki-67. The cell viability was evaluated with MTT assay, while the cell migration was evaluated by Transwell migration assay. Results: Ki-67 was shown to be highly expressed in 79.7%(55/69) of medullary thyroid cancer cases both in transcriptional and protein level. Moreover, the highly expressed of Ki-67 was positively correlated with the malignancies of medullary thyroid cancer. Knock-down of Ki-67 in TT cell was found to reduce cell migration. In addition, the follow-up visit of these patients demonstrated that 5-year survival rate was lower in patients with high expression of Ki-67. Conclusions: Our study suggested that medullary thyroid tumor tissue may highly expressed Ki-67, which was associated with tumor size, lymph node-metastasis, tumor stage and CT. Increased Ki-67 may play important roles in tumor proliferation and migration. Ki-67 could serve in particular as a prognostic marker and therapeutic target for medullary thyroid cancer.