Endocrine-Related Cancer 16
(2)
455
-466
DOI: 10.1677/ERC-09-0002
Copyright © 2009 by the Society for Endocrinology
Expression of the melanoma-associated antigen is associated with progression of human thyroid cancer
Sonia Cheng1,2,
Wei Liu1,
Moises Mercado2,
Shereen Ezzat3 and
Sylvia L Asa1
1 Department of Pathology, University Health Network and the Ontario Cancer Institute, 200 Elizabeth Street, 11th Floor, Toronto, Ontario, Canada M5G 2C4
2 Servicio de Endocrinología, Unidad de Investigación en Endocrinología Experimental, Hospital de Especialidades, IMSS, Mexico City, Mexico
3 Department of Medicine, University Health Network and the Ontario Cancer Institute, 600 University Avenue, Toronto Ontario, Canada M5G 1X5
(Correspondence should be addressed to S L Asa is at Department of Pathology, University Health Network and the Ontario Cancer Institute; Email: sylvia.asa{at}uhn.on.ca)
Thyroid cancer exhibits a spectrum from relatively indolent tumors to tumors that are invasive, metastatic, or progress to poorly differentiated carcinoma. Microarray expression analysis of thyroid cancer cell lines has implicated a member of the melanoma-associated (MAGE) family of cancer–testis antigens in thyroid cancer development and progression. We performed this study to validate the role of MAGE in human thyroid cancers. A tissue microarray (TMA) of samples from 375 patients with thyroid cancer was analyzed with immunohistochemistry (IHC) to localize MAGE. Western blotting of fractionated proteins from MAGE-transfected cells was used to confirm intracellular localization of proteins. Automated analysis of TMA samples was evaluated and subjected to statistical analysis. MAGE immunoreactivity was identified in nuclear and cytoplasmic compartments of normal and malignant tissues. Specificity of staining was proved by fractionation studies that confirmed MAGE expression in nucleus and cytoplasm. Normal thyroid tissue exhibited weak cytoplasmic and strong nuclear MAGE reactivity. Tumors exhibited an increase in cytoplasmic MAGE scores that correlated with clinical behavior: larger tumors had higher MAGE scores, and there was a positive and significant correlation between MAGE cytoplasmic score and the number of histologically proven lymph node metastases. There was a statistically significant negative correlation between cytoplasmic MAGE and the percentage of p53-positive nuclei. Our data confirm gene-profiling evidence that members of the MAGE family play a role in thyroid cancer progression. The use of TMA analyses identifies IHC techniques that are translatable to the clinical setting for prognostic assessment of patients with thyroid cancer.
Copyright © 2009 by the Society for Endocrinology.