The Significance of Immunohistochemical Expression of Sphingosine Kinase-1 and Galectin-3 in Differentiation Between Follicular Adenoma, Non-invasive Follicular Tumor with Papillary Nuclear Features and Follicular Variant Papillary Thyroid Carcinoma

Background and Study Aims: This study aims to evaluate the frequency of sphingosine kinase-1 (SPHK-1) and galectin 3 (Gal-3) immunohistochemical (IHC) expression in noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), follicular adenoma (FA), and follicular variant of papillary thyroid carcinoma (FVPTC), as well as the relationship between SPHK-1 and Gal 3 IHC expression in these thyroid lesions. Patients and Methods: 56 individuals underwent IHC analysis to evaluate the expression of the SPHK-1 and Gal-3 proteins. Results: The findings showed a significant correlation between FVPTC and elevated expression of SPHK-1 and Gal-3 (p < 0.001 for both markers). Gal-3 expression did not vary statistically significantly between FA and NIFTP patients (p = 0.271). The difference in the expression of SPHK-1 in FA and NIFTP patients was statistically significant (p < 0.001). Conclusions: Our results showed that both SPHK-1 and Gal-3 expression have diagnostic value for FVPTC. As an innovative strategy, only SPHK-1 could be used as a diagnostic factor for NIFTP.