Diagnostic and prognostic utility of TROP-2, SLP-2, and CXCL12 expression in papillary thyroid carcinoma

BACKGROUND: Papillary thyroid carcinoma (PTC) is the most frequent thyroid malignancy. Histopathological examination is widely accepted as the gold standard test for the diagnosis of PTC. However, the histopathological examination sometimes can't differentiate PTC from other thyroid diseases. Differentiating PTC from other thyroid diseases is essential for a therapeutic approach and prognosis. OBJECTIVES: The current study was performed to investigate the utility of TROP-2, SPL-2, and CXCL12 mRNA and protein expression in discriminating PTC from other thyroid diseases that mimic PTC. METHODS: The current study was performed on 75 cases of surgically resected thyroid glands. The cases were distributed in two groups: the PTC group and the non-PTC group. The PTC group consisted of 35 cases (25 patients of the classic PTC variant and 10 patients of the PTC follicular variant). The non-PTC group consisted of 40 cases (10 cases were multinodular goiter, 5 cases were Graves' disease, 5 cases were Hashimoto thyroiditis, 15 patients were follicular adenoma (FA) and 5 cases were follicular carcinoma). TROP-2 , SPL-2, and CXCL12 mRNA expression were estimated by qRT-PCR, and protein expression was estimated by immunohistochemistry. RESULTS: There were upregulated TROP-2, SPL-2, and CXCL12 mRNA and protein expressions in PTC compared to non-PTC (P < 0.001, for each). There was a statistically significant upregulation in the mRNA expression of the three genes among PTC cases with larger tumor sizes (P < 0.001, for each), those with tumor stages III and IV (P = 0.008, 0.002 and < 0.001 respectively), and those with LN metastasis (P < 0.001, for each). Moreover, there was a statistically significant upregulation in CXCL-12 gene expression among PTC cases with extra-thyroid extension (P < 0.001). CONCLUSION: mRNA expression of TROP-2, SPL-2, and CXCL12 among PTC cases increased in larger tumor size, tumor stages III and IV, and LN metastasis. Moreover, there was an increase in CXCL-12 gene expression among PTC cases with extra-thyroid extension. Thus, TROP-2, SPL-2, and CXCL12 expressions could be possible diagnostic and prognostic markers in PTC.