Immunohistochemical Expression of Galectin-3 and Cytokeratin 19 in the Spectrum of Thyroid Neoplasms

Abstract

Introduction: In systemic malignancies, thyroid carcinoma represents only 1%, but it is the most common endocrine malignancy with poor prognosis. Fine Needle Aspiration (FNA) is considered a requisite tool in providing a rational advent for the clinical management of these nodules. However, when solely based on cytopathological assessment, FNA leads to imprecise biopsy results in 10-20% of all cases. So, immunohistochemical markers, Galectin-3 (Gal-3) and Cytokeratin 19 (CK19) have received considerable attention as diagnostic marker for thyroid cancer. Aim: To study the expression of Gal-3 and CK19 in different thyroid neoplasms. Materials and Methods: This cross-sectional study was conducted at a tertiary care hospital from January 2019 to January 2021 on 120 cases. The thyroidectomy specimens received were fixed in 10% buffered formalin followed by gross examination. The paraffin embedded tissue blocks were subsequently stained for Haematoxylin and Eosin stain (H&E) followed by histopathological reporting. Qualitative immunohistochemical assessment of the marker Gal-3 and CK19 was performed on representative histologic sections of the thyroid neoplasms. Data were analysed using Graph Pad Instat 3. Results: The positive expression of Gal-3 was significantly more in malignant tumours (87.5%) than in benign (36.0%) (p-value <0.001). In Papillary Thyroid Carcinomas (PTC) and in Follicular Variant of Papillary Thyroid Carcinomas (FVPTC) expression of Gal-3 was notably higher than in Follicular Adenoma (FA) (p-value=0.01 and p-value=0.0001, respectively). Follicular Thyroid Carcinomas (FTC) had higher expression FA (p-value=0.003). In malignant tumours (71.8%), positive expression of CK19 was significantly more than benign tumours (24.0%) (p-value <0.001). Significant difference in expression of CK19 was seen between PTC and FTC (p-value=0.019). Between PTC and FA, differences in expression were significant (p-value <0.001). Significant difference in expression was also seen between FVPTC and FTC (p-value=0.032) as well as with FA (p-value=0.028). Conclusion: The most sensitive marker is Gal-3 for the diagnosis of thyroid malignancies. When combined with CK19, the specificity increases in identifying the thyroid cancers. More combination of markers together with Gal-3 and CK19 can be useful in the distinction between malignant and benign thyroid tumours because it is essential for further treatment and long-term management of the patient.

Keywords

• benign lesions
• fine needle aspiration
• malignant
• markers
• thyroidectomy