Imaging, Diagnosis, Prognosis A High-Throughput Proteomic Approach Provides Distinct Signatures for Thyroid Cancer Behavior Sonia Cheng 1,2 , Stefano Serra 1 , Moises Mercado 3 , Shereen Ezzat 2 , and Sylvia L. Asa 1,2 Abstract Purpose: Well-differentiated thyroid cancer (WDTC) is the most frequent form of endocrine neoplasia. One of the main challenges in the management of this disease is distinguishing low-risk patients who can be treated by surgical resection of the lesion from those with a high likelihood of recurrence who need a more extensive approach, including total thyroidectomy and radioiodine ablation. Experimental Design: A tissue microarray (TMA) comprising 410 cases of WDTC was constructed with risk estimates for the following features: extrathyroidal extension, lymph node metastases, and vascular invasion. The variables examined were morphologic classification, candidate genetic, and proteomic biomarkers. Results: BRAF (Raf kinase type B) mutant carriers showed increased risk of developing invasion compared with wild-type (WT) cases. However, when classified morphologically, classic papillary thyroid carcinomas (PTC) showed much higher risk estimates for invasive features compared with follicular variant PTCs (FVPTC); within these morphologic subgroups, BRAF mutational status did not provide independent risk estimates. Staining intensities for membranous galectin-3 (Gal3), HBME-1, and CK19 and nuclear Gal3 were statistically validated as markers of aggressive behavior. Estrogen receptor beta (ERb) was overexpressed in lesions with invasive behavior. The utility of these biomarkers remained statistically significant in the FVPTC. In contrast, a different set of biomarkers proved effective in classic PTC where upregulation of cyclin D1, loss of p27, and overexpression of ERb were associated with invasive behavior. Conclusion: Different proteomic signatures validate the distinction of classic and FVPTC and provide a practical clinical mechanism to predict the thyroid cancer behavior and stratify patients for clinical management. Clin Cancer Res; 17(8); 2385–94. Ó2011 AACR. Introduction The most common endocrine malignancy is papillary thyroid carcinoma (PTC), a tumor that has several mor- phologic variants, the most common being classic PTC and follicular variant PTC (FVPTC; ref. 1). The incidence of this malignancy has been increasing recently, possibly because of increased awareness of the disease, increasingly sensitive diagnostic methods that detect ever smaller lesions, and ill- defined environmental pathogenetic factors (2). Most PTCs are diagnosed when they measure less than 3 cm; they are most frequent in women younger than 55 years. PTC is one of the most curable cancers. The main challenge for clinicians treating this condition is to distin- guish high-risk from low-risk patients. This is of paramount importance, although high-risk patients require an aggres- sive approach with total thyroidectomy and radioiodine ablation, whereas for low-risk patients, a simple hemithyr- oidectomy suffices. Thus, precise categorization of these patients has profound impact on clinical management and therefore on treatment-related morbidity and cost. Several prognostic scales have been proposed for thyroid cancer (3); although they are effective in predicting long- term mortality in patients with advanced lesions, they are poor at predicting disease recurrence and metastases in the majority of PTCs that are low-risk lesions. The relative indolence of these tumors has resulted in a paucity of large-scale clinical trials by comparing conservative and aggressive management approaches, and the majority of patients are subjected to total thyroidectomy with radio- iodine ablation. Molecular biomarkers have been sought to more accu- rately predict biological behavior in PTC, but have been validated in relatively small numbers of patients followed Authors' Affiliations: 1 Department of Pathology; 2 Ontario Cancer Insti- tute, University Health Network, Toronto, Ontario; 3 Servicio de Endocri- nología, Unidad de Investigaci  on en Endocrinología Experimental, Hospital de Especialidades, IMSS, Mexico City, Mexico Note: Supplementary data for this article are available at Clinical Cancer Research Online (http://clincancerres.aacrjournals.org/). Corresponding Author: Sylvia L. Asa, Department of Pathology and Ontario Cancer Institute, University Health Network, 200 Elizabeth Street, 11th Floor, Toronto, ON M5G 2C4. Phone: 416-340-4802; Fax: 416-340- 5517. E-mail: sylvia.asa@uhn.on.ca doi: 10.1158/1078-0432.CCR-10-2837 Ó2011 American Association for Cancer Research. Clinical Cancer Research www.aacrjournals.org 2385 Downloaded from http://aacrjournals.org/clincancerres/article-pdf/17/8/2385/2003873/2385.pdf by guest on 16 June 2022