Published in:
01-12-2013
The Role of Epithelial Mesenchymal Transition Markers in Thyroid Carcinoma Progression
Authors:
Celina Montemayor-Garcia, Heather Hardin, Zhenying Guo, Carolina Larrain, Darya Buehler, Sofia Asioli, Herbert Chen, Ricardo V. Lloyd
Published in:
Endocrine Pathology
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Issue 4/2013
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Abstract
Understanding the molecular mechanisms involved in thyroid cancer progression may provide targets for more effective treatment of aggressive thyroid cancers. Epithelial mesenchymal transition (EMT) is a major pathologic mechanism in tumor progression and is linked to the acquisition of stem-like properties of cancer cells. We examined expression of ZEB1 which activates EMT by binding to the E-box elements in the E-cadherin promoter, and expression of E-cadherin in normal and neoplastic thyroid tissues in a tissue microarray which included 127 neoplasms and 10 normal thyroid specimens. Thyroid follicular adenomas (n = 32), follicular thyroid carcinomas (n = 28), and papillary thyroid carcinomas (n = 57) all expressed E-cadherin and were mostly negative for ZEB1 while most anaplastic thyroid carcinomas (ATC, n = 10) were negative for E-cadherin, but positive for ZEB1. A validation set of 10 whole sections of ATCs showed 90 % of cases positive for ZEB1 and all cases were negative for E-cadherin. Analysis of three cell lines (normal thyroid, NTHY-OR13-1; PTC, TPC-1, and ATC, THJ-21T) showed that the ATC cell line expressed the highest levels of ZEB1 while the normal thyroid cell line expressed the highest levels of E-Cadherin. Quantitative RT-PCR analyses showed that Smad7 mRNA was significantly higher in ATC than in any other group (p < 0.05). These results indicate that ATCs show evidence of EMT including decreased expression of E-cadherin and increased expression of ZEB1 compared to well-differentiated thyroid carcinomas and that increased expression of Smad7 may be associated with thyroid tumor progression.