1. ¹Department of Pathology, The Ohio State University Medical center, Columbus, OH, USA
2. ²Human Cancer Genetics Program, Comprehensive Cancer Center, The Ohio State University Medical center, Columbus, OH, USA
3. ³Department of Statistics, The Ohio State University Medical center, Columbus, OH, USA
4. ⁴Division of Endocrinology, Diabetes, and Metabolism, Department of Internal Medicine, The Ohio State University Medical center, Columbus, OH, USA
5. ⁵Division of Nuclear Medicine, Department of Radiology, The Ohio State University Medical center, Columbus, OH, USA

Correspondence: Dr ML Prasad, MD, Department of Pathology, The Ohio State University Medical Center, E 418 Doan Hall, 410 W 10th Ave., Columbus, OH 43210, USA. E-mail: prasad-1@medctr.osu.edu

Received 13 May 2004; Revised 22 June 2004; Accepted 22 June 2004; Published online 23 July 2004.

Abstract

The diagnosis of thyroid tumors is critical for clinical management; however, tumors with follicular architecture often present problems. We evaluated the diagnostic use of the protein expression of four genes that were found to be upregulated in papillary thyroid carcinoma compared to normal thyroid (LGALS3, FN1, CITED1 and KRT19), and of the mesothelial cell surface protein recognized by monoclonal antibody HBME1 in thyroid tumors. Tissues from 85 carcinomas (67 papillary, six follicular, eight Hürthle cell and four anaplastic) and 21 adenomas were evaluated by immunohistochemistry for the expression of these gene protein products, for example, galectin-3 (GAL3), fibronectin-1 (FN1), CITED1, cytokeratin-19 (CK19) and HBME1. Non-neoplastic thyroids (29 adenomatous and 14 thyrotoxic hyperplasia, and 59 normal) were also studied. The expression of all five proteins was significantly associated with malignancy, and highly specific (90%) for carcinoma compared to adenoma. GAL3, FN1 and/or HBME1 expression was seen in 100% of carcinomas (85/85) and in 24% of adenomas (5/21). Coexpression of multiple proteins was seen in 95% of carcinomas and only 5% of adenomas (P<0.0001). Coexpression of FN1 and GAL3 (FN1+GAL3+, 70/85) or FN1 and HBME1 (FN1+HBME1+, 53/85) was restricted to carcinomas, while their concurrent absence (FN1-GAL3- or FN1-HBME1-, 18/21 adenoma) was highly specific (96%) for benign lesions. Among non-neoplastic thyroids, adenomatous hyperplasia frequently expressed GAL3 (n=16), CK19 (n=9) and CITED1 (n=7), but the expression was predominantly focal in contrast to the diffuse expression in carcinomas. An immunohistochemical panel consisting of GAL3, FN1 and HBME1 may be useful in the diagnosis of follicular cell-derived thyroid tumors.