Diagnostic Value of TROP2 Expression in Papillary Thyroid Carcinoma

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.

Application of Immunohistochemistry in Papillary Thyroid Carcinoma

Immunohistochemistry (IHC) is an economic and precise method to localize the presence of specific protein at cellular level in tissue. Although many papillary thyroid carcinomas do not require IHC to render a diagnosis, there are certain scenarios in which IHC are important. The major diagnostic applications of IHC include confirmation of papillary thyroid carcinoma in sites other than the thyroid, distinguish papillary thyroid carcinoma from other primary thyroid neoplasms in thyroid, and identify papillary thyroid carcinoma from secondary tumors to the thyroid. At research level, IHC could help identify prognostic information, identify underlying genetic alterations, and predict response to treatment in papillary thyroid carcinoma. The understanding of principle and recent advances in IHC will improve the diagnosis and management of patients with thyroid lesions including papillary thyroid carcinoma.

TROP2 modulates the progression in papillary thyroid carcinoma

Background: Tumor-associated calcium signal transducer 2 (TROP2) is over expressed in various kinds of human cancers and plays important roles in the proliferation, invasion and metastasis of tumor cells. However, the expression and molecular mechanism of TROP2 in thyroid papillary carcinoma (PTC) are unclear. Methods: The expressions of TROP2 in PTC and control tissue were detected by real-time reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. The proliferation and invasion of PTC cell lines were examined by cell cloning and transwell assays. RNA sequencing analysis and public data analysis were assessed to investigate the potential mechanisms of TROP2 in PTC. Gene correlation analysis was conducted to explore the association between TROP2 and the related gene ISG15 in patients with PTC. Results: The expression of TROP2 was significantly higher in PTC than control. The high expression of TROP2 protein was associated with lymph node metastasis, tumor size and capsular infiltration (P<0.05). SiRNA-mediated TROP2 gene expression silencing can significantly inhibit proliferation and migration of PTC cells. ISG15 decreased in TROP2 siRNA PTC cells and increased in PTC patients significantly. There was a significant correlation between the expression of TROP2 and ISG15 in PTC patients. TROP2 interacted directly with ATP6V1A, CEBPA and SOX5 and then further interacted with the immune genes. TROP2 expression and tumor-infiltrating immune cells were also correlated in thyroid cancer microenvironment. Conclusions: TROP2 promotes the development of PTC. TROP2 expression was correlated with ISG15 and tumor-infiltrating immune cells in thyroid cancer.

Trop2 binding IGF2R induces gefitinib resistance in NSCLC by remodeling the tumor microenvironment

Gefitinib has shown good efficacy in treating recurrent or advanced non-small cell lung cancer (NSCLC), but the drug resistance remains a clinical challenge in medical oncology. In addition, the complex interaction between tumor cells and heterogeneous stromal cells in the adjacent tumor microenvironment (TME) is also an important contributor to drug resistance. So, it is very necessary to detect the related target genes before and after gefitinib treatment dynamically. In this study, the relationship between Trop2 and gefitinib resistance in NSCLC was investigated, and the underlying mechanism was explored. Results showed that Trop2 was associated with EGFR gene mutation and drug resistance in clinical tissues. Trop2 was confirmed to induce gefitinib resistance in NSCLC, and Trop2 binding IGF2R promoted the IGF2-IGF1R-Akt axis to enhance gefitinib resistance and remodeling the TME in NSCLC. Notably, silencing of Trop2 in cancer cells combined with IGF1R inhibitor significantly decreased the proliferation of tumor cells and reshaped the NSCLC TME in vivo and in vitro, including the recruitment of macrophages. These findings deepened the understanding of the function of Trop2 and the involved mechanisms of gefitinib resistance, and may provide new molecular targets for NSCLC with gefitinib resistance.