Diagnostic value Of Human Trophoblastic Transmembrane Glycoprotein (TROP-2) Expression In Diagnosing Papillary Thyroid Carcinoma Immunohistochemical Study

Background: Diagnosis of papillary thyroid carcinoma (PTC) depends on characteristic histopathological features. However, there may be cases with inconsistent features, necessitating the use of immunohistochemical markers. IHC stains, such as HBME-1, galectin-3, and CK19, aid in the diagnosis of PTC; however, varying degrees of sensitivity and specificity have been reported. Recent studies have identified TROP-2 as a novel promising marker in the diagnosis of PTC. Aim: This study aimed to investigate the value of TROP-2 expression in the diagnosis of PTC and its differentiation from benign thyroid lesions and low-risk neoplasms (NIFTP). Material and methods: This retrospective study was carried out on 51 cases classified according to the 5th edition of the WHO classification 2022 as follows: 13 benign thyroid lesion cases, 12 low-risk neoplasms (NIFTP) cases, and 26 papillary thyroid carcinoma cases. 6 cases of breast carcinoma were taken as a control. Clinicohistopathological parameters were correlated with TROP-2 expression. Results: In the current study, there was a positive, significant statistical correlation(P<0.01) between TROP-2 expression and the studied cases, as 7.7% of benign cases, 50% of low-risk neoplasms cases, and 92.3% of malignant cases were positive. Conclusion: TROP-2 may be a potentially valuable marker that can aid in the diagnosis of PTC and differentiate it from its benign mimics and low-risk neoplasms (NIFTP) with high sensitivity and specificity.