TROP-2 expression in papillary thyroid cancer: a preliminary cyto-histological study

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.

The Relationship between Trop-2, Chemotherapeutic Drugs, and Chemoresistance

Trop-2 is a highly conserved one-pass transmembrane mammalian glycoprotein that is normally expressed in tissues such as the lung, intestines, and kidney during embryonic development. It is overexpressed in many epithelial cancers but is absent in non-epithelial tumors. Trop-2 is an intracellular calcium signal transducer that participates in the promotion of cell proliferation, migration, invasion, metastasis, and probably stemness. It also has some tumor suppressor effects. The pro-tumoral actions have been thoroughly investigated and reported. However, Trop-2's activity in chemoresistance is less well known. We review a possible relationship between Trop-2, chemotherapy, and chemoresistance. We conclude that there is a clear role for Trop-2 in some specific chemoresistance events. On the other hand, there is no clear evidence for its participation in multidrug resistance through direct drug transport. The development of antibody conjugate drugs (ACD) centered on anti-Trop-2 monoclonal antibodies opened the gates for the treatment of some tumors resistant to classic chemotherapies. Advanced urothelial tumors and breast cancer were among the first malignancies for which these ACDs have been employed. However, there is a wide group of other tumors that may benefit from anti-Trop-2 therapy as soon as clinical trials are completed.

Targeting Trop-2 in cancer: Recent research progress and clinical application

The development of new antitumor drugs depends mainly upon targeting tumor cells precisely. Trophoblast surface antigen 2 (Trop-2) is a type I transmembrane glycoprotein involved in Ca2+ signaling in tumor cells. It is highly expressed in various tumor tissues than in normal tissues and represents a novel and promising molecular target for caner targeted therapy. Up to now, the mechanisms and functions associated with Trop-2 have been extensively studied in a variety of solid tumors. According to these findings, Trop-2 plays an important role in cell proliferation, apoptosis, cell adhesion, epithelial-mesenchymal transition, as well as tumorigenesis and tumor progression. In addition, Trop-2 related drugs are also being developed widely. There are a number of Trop-2 related ADC drugs that have demonstrated potent antitumor activity and are currently been studied, such as Sacituzumab Govitecan (SG) and Datopotamab Deruxtecan (Dato-Dxd). In this study, we reviewed the progress of Trop-2 research in solid tumors. We also sorted out the composition and rationale of Trop-2 related drugs and summarized the related clinical trials. Finally, we discussed the current status of Trop-2 research and expanded our perspectives on its future research directions. Importantly, we found that Trop-2 targeted ADCs have great potential for combination with other antitumor therapies. Trop-2 targeted ADCs can reprogramme tumor microenvironment through multiple signaling pathways, ultimately activating antitumor immunity.

TROP2 is a Good Indicator for Infiltrative Nature of Carcinoma Rather than Diagnosing Malignancy in Thyroid

TROP2 is a glycoprotein which is expressed in carcinomas rather than normal tissues and associated with poor prognosis. Immunohistohemical TROP2 staining was determined to be useful for diagnosing papillary thyroid carcinoma (PTC). In this study, we aimed to find out relationship between TROP-2 expression and the diagnosis of PTC, and clinico pathological parameters. This retrospective study was conducted on 270 cases (145 malignant and 124 benign). All histopathological parameters were re-evaluated blindly. We used 3 different scores for positivity for TROP2 expression (TES: Total estimation score, 5%, IRS:Immunoreactive score). Sensitivity was respectively according to TES, 5%and IRS; 55.5%, 54.1%, 51.4%. Specificity was 98.4% in all different scores. TROP2 positivity was correlated with older age in 5% score and TES. Absence of encapsulation, presence of infiltrating spreading, perineural invasion, extra thyroidal extension, tall cell and/or hobnail differentiation were associated with TROP2 expression in three different scores. Presence of lymphatic invasion was correlated with TROP2 positivity in 5% score and IRS. TROP2 expression was inversely proportional to follicular variant PTC and tumour size in 5% score. TROP-2 is a marker for aggressive behaviour rather than detecting malignancy, but if it stained and not malignant, it may also have potential for determining precursor lesion that demands further studies. Additionally, in 3 different scores, TES was most sensitive, but most variable that had correlation with TROP2 was seen at 5% score.

Systematic Review and Meta-Analysis to Identify the Immunocytochemical Markers Effective in Delineating Benign from Malignant Thyroid Lesions in FNAC Samples

Conventional cytology-based diagnosis for thyroid cancer is limited with more than 30-45% of nodules categorized as indeterminate, necessitating surgery for confirming or refuting the diagnosis. This systematic review and meta-analysis were aimed at identifying immunocytochemical markers effective in delineating benign from malignant thyroid lesions in fine needle aspiration cytology (FNAC) samples, thereby improving the accuracy of cytology diagnosis. A systematic review of relevant articles (2000-2021) from online databases was carried out and the search protocol registered in PROSPERO database (CRD42021229121). The quality of studies was assessed using QUADAS-2. Review Manager 5.4.1 from Cochrane collaboration and MetaDisc Version 1.4 was used to conduct the meta-analysis. Bias in the studies were visually analyzed using funnel plots, and statistical significance was evaluated by Egger's test. Systematic review identified 64 original articles, while meta-analysis in eligible articles (n = 41) identified a panel of 5 markers, Galectin-3, HBME-1, CK-19, CD-56, and TPO. Assessment of the diagnostic performance revealed that Gal-3 (sensitivity: 0.81; CI: 0.79-0.83; specificity: 0.84; CI: 0.82-0.85) and HBME-1 (sensitivity: 0.83; Cl: 0.81-0.86; specificity: 0.85; CI: 0.83-0.86) showed high accuracy in delineating benign from malignant thyroid nodules. Efficacy analysis in indeterminate nodules showed Gal-3 and HBME-1 have high specificity of 0.86 (CI 0.84-0.89) and 0.82 (CI 0.78-0.86), respectively, and low sensitivity of 0.76 (CI 0.72-0.80) and 0.75 (CI 0.70-0.80), respectively. Diagnostic odds ratio (DOR) of Galectin-3 and HBME-1 were 39.18 (CI 23.38-65.65) and 24.44 (CI 11.16-53.54), respectively. Significant publication bias was observed for the markers Galectin-3 and CK-19 (p < 0.05). The panel of 5 markers identified from this meta-analysis are high-confidence candidates that need to be validated in thyroid cytology to establish their efficacy and enable clinical applicability.

TROP-2 and 5hmC expression in follicular-patterned thyroid neoplasm emphasizing tiny well-formed papillae

BACKGROUND

Follicular-patterned thyroid neoplasms (FPTNs), characterized by predominantly follicular growth pattern, represent diverse pathological entities. We aimed to study the nuclear features and the immunoexpression of trophoblast cell-surface antigen 2 (TROP-2) and 5-hydroxymethylcytosine (5hmC) in FPTNs.

DESIGN

FPTNs were divided into 4 groups: I) noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), II) encapsulated follicular variant of papillary thyroid carcinoma (FVPTC) with capsular invasion, III) infiltrative FVPTC, and IV) PTC with a predominantly follicular pattern and well-formed papillae (<1%). Nuclear characteristics were evaluated by image analysis. TROP-2 and 5hmC immunostains were analyzed correlating with histological features using QuPath.

RESULTS

From the group I to II, III, and IV, there is a gradual increase in nuclear atypia in terms of the nuclear area, max caliper, perimeter, circularity, and hematoxylin OD means (corresponding to nuclear enlargement, membrane irregularity, and clearing). A similar trend is observed in the TROP-2 expression. 5hmC expression is highly preserved in groups I, II, and III in contrast to a significant loss in group IV. Group IV tumors show more frequent regional lymph node involvement and the highest BRAF V600E mutation rate.

CONCLUSION

Among FPTNs, group IV tumors exhibit the most advanced nuclear atypia, highest TROP-2 expression, significant 5HMC expression loss, frequent regional lymph node involvement, and the highest BRAF V600E mutation rate. Our data further support that the presence of any true papillae should be an exclusion criterion for NIFTP. Therefore, well-formed papillae even if very minute (<1% of the tumor) should not be overlooked.

TROP-2, 5hmC, and IDH1 Expression in Anaplastic Thyroid Carcinoma

BACKGROUND

Anaplastic thyroid carcinoma (ATC), a highly aggressive malignancy, has no effective treatment to date. Trophoblast cell-surface antigen 2 (TROP-2), a transmembrane glycoprotein, has been suggested to be a promising novel target for sacituzumab govitecan, an antibody-drug conjugate. 5-Hydroxymethylcytosine (5hmC) has a role in tumor suppression and promoting modification. Additionally, isocitrate dehydrogenase 1 (IDH1) mutations are strongly associated with increased overall survival in gliomas and worse prognosis in leukemias. This study attempts to evaluate the immunoexpression of TROP-2, 5hmC, and IDH1 in ATCs and to determine their potential impact in targeted therapy.

METHODS

Twenty-four ATCs were retrieved, with 9 cases that occurred de novo and 15 cases derived from either papillary thyroid carcinoma (PTC) or follicular thyroid carcinoma (FTC). Sections were immunostained with TROP-2, 5hmC, and IDH1 antibodies, and evaluated using the QuPath program. The t tests were performed using SPSS software.

RESULTS

TROP-2 was detected in 12 ATCs with 9 cases demonstrating a high expression and in all PTC components, and absent in all FTC components of secondary ATCs. 5hmC expression was moderately reduced in PTC and FTC components and markedly reduced in ATC. The entire cohort showed a total absence of IDH1.

CONCLUSIONS

Increased TROP-2 immunoexpression in some ATCs supports that these patients may potentially benefit from an antibody-drug conjugate therapy targeting TROP-2. Markedly reduced 5hmC expression suggests that 5hmC may be used as potential therapeutic targets for ATC. The total lack of IDH1 R132H mutation by immunostain indicates that it has no prognostic and therapeutic value in ATC.

Diagnostic Value of TROP2 Expression in Papillary Thyroid Carcinoma

Papillary thyroid carcinoma (PTC) represents the most common primary malignant thyroid lesion in all age groups. As diagnosis of PTC could be challenging in some cases and borderline nuclear features could be seen in some benign mimickers, several immunohistochemical markers are proposed to be helpful for making the correct diagnosis. In this study the authors investigated the diagnostic value of transmembrane glycoprotein (TROP2) for differentiating PTC from other thyroid follicular lesions. A total of 155 total thyroidectomy specimens including 84 cases of PTC and 71 cases of non-PTC were investigated. Among non-PTC group, 45 cases were follicular neoplasms and 26 cases were Hashimoto thyroiditis. TROP2 expression was observed in 82 of 84 cases of PTC group. In contrast only 5 cases of non-PTC group, all from Hashimoto thyroiditis specimens, showed positive expression. The sensitivity, specificity, positive predictive value, and negative predictive value of TROP2 for diagnosis of PTC was 98%, 93%, 94%, and 97%, respectively. The authors concluded that high sensitivity and specificity of TROP2 as well as its uniform negative reaction in follicular adenoma and carcinoma makes it a valuable immunohistochemical marker for diagnosis of PTC.

Trop2: Jack of All Trades, Master of None

Trophoblast cell surface antigen 2 (Trop2) is a widely expressed glycoprotein and an epithelial cell adhesion molecule (EpCAM) family member. Although initially identified as a transmembrane protein, other subcellular localizations and processed forms were described. Its congenital mutations cause a gelatinous drop-like corneal dystrophy, a disease characterized by loss of barrier function in corneal epithelial cells. Trop2 is considered a stem cell marker and its expression associates with regenerative capacity in various tissues. Trop2 overexpression was described in tumors of different origins; however, functional studies revealed both oncogenic and tumor suppressor roles. Nevertheless, therapeutic potential of Trop2 was recognized and clinical studies with drug-antibody conjugates have been initiated in various cancer types. One of these agents, sacituzumab govitecan, has been recently granted an accelerated approval for therapy of metastatic triple-negative breast cancer. In this article, we review the current knowledge about the yet controversial function of Trop2 in homeostasis and pathology.

Diagnostic Value of TROP-2 and CK19 Expression in Papillary Thyroid Carcinoma in Both Surgical and Cytological Specimens

Papillary thyroid carcinoma (PTC) represents the most common primary malignant thyroid tumor and its diagnosis is dependent on the presence of classic nuclear features that are sometimes seen in some non-neoplastic and benign lesions. Several immunohistochemical markers are used individually or in combination to help in differentiation of PTC from mimickers. The aim of the current study was to assess the diagnostic value of TROP-2 and cytokeratin 19 (CK19) expression in differentiating PTC from other mimickers both singly and in combination. The current study was carried out on 77 surgical specimens (56 PTC and 21 non-neoplastic cases) and 12 cytological specimens (4 THY2, 6 THY4, and 2 THY5). TROP-2 was negative in 81% of non-neoplastic surgical specimens and in 100% of THY2 cytological specimens while it was positive in 71.4% of PTC surgical specimens and 100% of THY4/THY5 cytological specimens. Sensitivity and specificity of TROP-2 positive expression for diagnosis of PTC in surgical specimens reached 71% and 81%, respectively, while it reached 100% for both in cytological specimens. Cytokeratin 19 showed positive expression in 85.7% of non-neoplastic surgical specimens and in 92.9% of PTC surgical specimens. Cytokeratin 19 showed negative expression in 75% of Thy2 cases while it was positive in all studied Thy4 and Thy5 cases. Sensitivity and specificity of CK19 total estimated score for diagnosis of PTC in surgical specimens were 78.6% and 66.7%, respectively, while it reached 100% and 75% in cytological specimens. Positive TROP-2 and CK19 expression in PTC were associated with lymph node metastasis. TROP-2 is a specific rather than sensitive marker while CK19 is a sensitive rather than specific marker in differentiating PTC from other mimickers in surgical specimens. The diagnostic validity of both markers was superior in diagnosis of classic PTC compared with follicular variant PTC. TROP-2 is superior to CK19 in diagnosis of PTC in cytological specimens. Both TROP-2 and CK19 could be used preoperatively in adjunct to hematoxylin and eosin for more confident diagnosis of thyroid cytology and along with radiology as predictors of lymph node metastasis.

Diagnostic Utility of Molecular and Imaging Biomarkers in Cytological Indeterminate Thyroid Nodules

Indeterminate thyroid cytology (Bethesda III and IV) corresponds to follicular-patterned benign and malignant lesions, which are particularly difficult to differentiate on cytology alone. As ~25% of these nodules harbor malignancy, diagnostic hemithyroidectomy is still custom. However, advanced preoperative diagnostics are rapidly evolving.This review provides an overview of additional molecular and imaging diagnostics for indeterminate thyroid nodules in a preoperative clinical setting, including considerations regarding cost-effectiveness, availability, and feasibility of combining techniques. Addressed diagnostics include gene mutation analysis, microRNA, immunocytochemistry, ultrasonography, elastosonography, computed tomography, sestamibi scintigraphy, [18F]-2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET), and diffusion-weighted magnetic resonance imaging.The best rule-out tests for malignancy were the Afirma® gene expression classifier and FDG-PET. The most accurate rule-in test was sole BRAF mutation analysis. No diagnostic had both near-perfect sensitivity and specificity, and estimated cost-effectiveness. Molecular techniques are rapidly advancing. However, given the currently available techniques, a multimodality stepwise approach likely offers the most accurate diagnosis, sequentially applying one sensitive rule-out test and one specific rule-in test. Geographical variations in cytology (e.g., Hürthle cell neoplasms) and tumor genetics strongly influence local test performance and clinical utility. Multidisciplinary collaboration and implementation studies can aid the local decision for one or more eligible diagnostics.

The Significance of TROP2 Expression in Predicting BRAF Mutations in Papillary Thyroid Carcinoma

BACKGROUND

Trophoblast antigen 2 (TROP2) is a human trophoblast cell-surface glycoprotein that is overexpressed in several types of epithelial cancers, and is suggested to be associated with an unfavorable prognosis. BRAF mutations are the most common genetic alteration in papillary thyroid carcinoma (PTC). We evaluated the correlation between TROP2 expression and BRAF mutation in PTC.

METHODS

First, we carried out pyrosequencing for BRAF mutations and immunohistochemistry for TROP2 expression with a tissue microarray consisting of 52 PTC cases. Membranous staining in at least 5% of tumor cells was designated as positive staining and we analyzed the relationship between TROP2 expression and diverse clinicopathological factors, including BRAF mutation. Second, we tested TROP2 mRNA expression in three thyroid cancer cell lines with BRAF mutations (BCPAP, SNU790, and 8505C) and a normal thyroid cell line. Additionally, we checked TROP2 protein levels in a normal thyroid cell line after introduction of the BRAF V600E mutation.

RESULTS

In this study, 21 of 26 cases with BRAF mutation showed TROP2 immunoreactivity, whereas all 26 cases without BRAF mutation showed no immunoreactivity for TROP2 with a statistically significant difference (p<.001). Upregulation of TROP2 mRNA was observed in all three thyroid cancer cell lines, but not in the normal thyroid cell line. Interestingly, however, the TROP2 expression was increased in the normal thyroid cell line after introduction of the BRAF V600E mutation.

CONCLUSIONS

Based on these results, we concluded that TROP2 expression is significantly associated with BRAF mutation and that TROP2 immunohistochemistry could be used for predicting BRAF mutations or diagnosing papillary thyroid carcinoma.

Trop2 enhances invasion of thyroid cancer by inducing MMP2 through ERK and JNK pathways

Background

Mounting evidence has showed that Tumor-associated calcium signal transducer 2 (Trop2) is upregulated in various kinds of human cancers and plays important roles in tumorigenesis. However, the expression status and functional significance of Trop2 in thyroid cancer are largely unknown.

Methods

We first determined the expression of Trop2 by using RNAseqV2 data sets for thyroid cancer deposited on The Cancer Genome Atlas (TCGA) website. The expression of Trop2 was then confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry assays. Cell invasion and migration were assessed by conducting Transwell and wound healing assays. Furthermore, we explored the underlying mechanisms by using real-time RT-PCR, Western blot, zymography, and luciferase reporter assays.

Results

In this study, we demonstrated that the expression of Trop2 was significantly elevated in thyroid cancer and that its expression level was correlated with the tumor-node-metastasis (TNM) staging and N classification. Dysregulation of Trop2 altered the invasive capability of thyroid cancer cells. Further mechanistic study revealed that MMP2 expression was upregulated by Trop2. Moreover, we found that the effects of Trop2 were dependent on ERK and JNK pathways. The results from clinical specimens showed that Trop2 expression correlated with MMP2 expression in primary thyroid cancer.

Conclusion

The current study suggests that elevated expression of Trop2 may represent an important molecular hallmark that is biologically and clinically relevant to the progression of thyroid cancer.