Potential diagnostic markers in nodular lesions of the thyroid gland: an immunohistochemical study

Aims: The differential diagnosis of thyroid nodules in routine practice can be problemmatic for both pathologists and clinicians. Effective treatment requires a determination of the biological nature of the lesions. For this reason, ancilliary diagnostic markers along with histological examination of the nodules may be useful. The objective of this study was to evaluate the diagnostic usefulness of novel markers in the diagnosis of hyperplastic and neoplastic nodules. Methods: Forty eight thyroid lesions forming four diagnostic groups including adenomatous goiters (AS), follicular adenomas (FA), follicular (FC) and papillary carcinomas (PC) were examined using standard immunohistochemical methods. Monoclonal antibodies against galectin-3, matrix metalloproteinases (MMPs) -2 and -7 and endothelial markers CD31 and CD105 were used. Results: The cytoplasmatic expression of galectin-3 was positive in all cases of papillary carcinoma. Moreover, statistically significant differences between fused groups of benign (AS and FA) and malignant lesions (FC and PC) were found Fischer's exact test (p = 0.0001). No significant differences in cytoplasmic expression of MMPs -2 and -7 and in vascular density assessed by using of both endothelial markers between benign lesions and malignant tumors were revealed. Conclusions: Galectin-3 appears to be a useful marker in the diagnosis of papillary carcinoma only. The matrix metalloproteinases-2 and -7 are not helpful in distinguishing hyperplastic and neoplastic thyroid nodules. Endothelial markers do not appear to be suitable for thyroid differential diagnosis. A panel of antibodies in the differential diagnosis of thyroid nodular lesions would seem most suitable and further studies with larger sets of patients are awaited.