Sensitivity and Specificity of Galectin-3 and Glypican-3 in Follicular-Patterned and Other Thyroid Neoplasms.

INTRODUCTION: Diagnosing follicular-patterned thyroid neoplasm can be quiet challenging in some cases, where an immunohistochemical profiling becomes mandatory. Galectin-3 may be a helpful tool for classical PTC diagnosis, but it cannot be considered as a diagnostic marker of malignancy. Glypican-3, in contrast, is not thoroughly studied in thyroid neoplasms.

AIM: Determine the sensitivity and specificity of galectin-3 and glypican-3 in diagnosing thyroid carcinoma and follicular-patterned thyroid carcinoma.

MATERIALS AND METHODS: A retrospective study was conducted on archival blocks diagnosed from pathology department between 2010 and 2012 including 17 cases of follicular adenoma, 16 cases of Classic Papillary Thyroid Carcinoma (PTC), 6 cases of Follicular Variant of Papillary Thyroid Carcinoma (FVPTC), 3 cases of follicular carcinoma, 5 cases of medullary carcinoma and 1 case of Hürthle cell carcinoma. The nearby non neoplastic (normal) thyroid follicles present in both adenoma and carcinoma cases were also evaluated.

STUDY DESIGN: Evaluation of both galectin-3 and glypican-3 expression using standard immunohistochemical techniques.

STATISTICAL ANALYSIS USED: Descriptive analysis of the variables and statistical significances were calculated by non-parametric chi-square test using the Statistical Package for the Social Sciences version 12.0 (SPSS).

RESULTS: Five (30%) and 4 (24%) out of the 17 studied follicular adenoma cases, were positively stained by galectin-3 and glypican-3 respectively, while 30 (97%) and 25 (81%) cases out of the studied 31 carcinoma cases were positively stained by galectin-3 and glypican-3 respectively. The sensitivity, specificity and diagnostic accuracy of galectin-3 vs. glypican-3 in discrimination between thyroid carcinoma and adenoma was 96.8%, 70.6%, and 87.5%vs. 81% 76.5% and 79% respectively. As for the discrimination between follicular-patterned thyroid carcinoma and follicular adenoma it was 90%, 71% and 78% vs. 90% 76.5% and 82%.

CONCLUSION: Glypican-3 is more specific while galectin-3 is more sensitive in diagnosing thyroid carcinoma while glypican-3 is more specific than galectin-3 in discriminating follicular-patterned neoplasm.