TROP-2 immunohistochemistry: a highly accurate method in the differential diagnosis of papillary thyroid carcinoma

An electrochemical biosensor to assay Trop-2 of breast cancer cells fabricated by methylene blue-assisted assembly of DNA nanoparticles

Human trophoblast surface cell antigen 2 (Trop-2) on the tumor cell membrane can not only serve as the target for chemotherapy drugs, but also as a biomarker for typing and prognosis of breast cancer; however, assay of Trop-2 is seriously hampered due to the limitations of available tool. Herein, we have designed and fabricated an electrochemical biosensor for the assay of Trop-2 based on methylene blue (MB)-assisted assembly of DNA nanocomposite particles (DNPs). Specially, the recognition between Trop-2 and its aptamer may activate the primer exchange reaction (PER) on an electrode surface to produce long single-strand DNA (ssDNA) which can be self-assembled into DNPs by electrostatic interaction between negative charged DNA and positive charged and electro-active MB molecules which can also be used to give electrochemical signal. By using this electrochemical biosensor, ultrasensitive detection of tumor cells with high Trop-2 expressions can be conducted, with the limit of detection (LOD) of 1 cell/mL. Moreover, this biosensor can be further used for accurately profiling Trop-2 expression of tumor cells in mouse tissues, suggesting its great potential in the precise definition of breast cancer.

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.

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.

Trop-2 and Nectin-4 immunohistochemical expression in metastatic colorectal cancer: searching for the right population for drugs' development

BACKGROUND

Trop-2 and Nectin-4 are transmembrane proteins overexpressed in many tumours and targets of antibody-drug conjugates (ADC). In metastatic colorectal cancer (mCRC), the role of Trop-2 and Nectin-4 has been poorly investigated.

METHODS

Tumour samples of patients randomised in the phase III TRIBE2 were assessed for Trop-2 and Nectin-4 expression.

RESULTS

Three hundred eighty-six tumours were assessed for Trop-2 expression. 90 (23%), 115 (30%) and 181 (47%) were Trop-2 high, medium and low, respectively. Patients with low Trop-2 tumours achieved longer PFS (12 versus 9.9 months, p = 0.047) and OS (27.3 versus 21.3 months, p = 0.015) than those with high/medium Trop-2 tumours. These findings were confirmed in multivariate analysis (p = 0.022 and p = 0.023, respectively). A greater OS benefit from treatment intensification with FOLFOXIRI/bevacizumab was observed in patients with high/medium Trop-2 tumours (p-for-interaction = 0.041). Two hundred fifty-one tumours were assessed for Nectin-4 expression. Fourteen (5%), 67 (27%) and 170 (68%) were high, medium and low, respectively. No prognostic impact was observed based on Nectin-4 expression and no interaction effect was reported between Nectin-4 expression groups and treatment arm.

CONCLUSIONS

In mCRC, expression levels of Trop-2 and Nectin-4 are heterogeneous, suggesting a target-driven development of anti-Trop2 and anti-Nectin-4 ADCs. Medium/high Trop-2 expression is associated with worse prognosis and higher benefit from chemotherapy intensification.

TROP2: a potential marker in diagnosis of thyroid neoplasms

BACKGROUND AND OBJECTIVES

The human trophoblast cell surface antigen (TROP-2), a transmembrane glycoprotein, has recently been investigated as a valuable marker of thyroid epithelial neoplasms. In this study, we aimed to demonstrate the diagnostic utility of TROP2 in thyroid neoplasms.

METHODS

A total of 308 cases, including 170 cases of different PTC variants, 50 cases of benign and non-neoplastic lesions, and 86 cases of other neoplasms (NIFT-P, poorly differentiated thyroid carcinoma, anaplastic thyroid carcinoma, follicular thyroid carcinoma, Hürthle cell carcinoma, and medullary thyroid carcinoma), were included in this study. Only membranous staining with TROP2 was considered positive.

RESULTS

In PTC, classical (n = 35), tall cell (n = 41), follicular (n = 39), solid (n = 19), hobnail (n = 10), Warthin-like (n = l0), columnar (n = 7), and oncocytic variant (n = 9) were 100%, 97.6%, 5.1%, 42.1%, 90%, 90%, 28.6%, and 33.3% positive, respectively. A negative reaction was observed in all 50 cases of benign and non-neoplastic lesions and also in surrounding normal thyroid tissue in all cases. Negative reactions were observed in 83 (n = 86) of other thyroid neoplasms including NIFT-P (n = 20), poorly differentiated thyroid carcinoma (n = 10), anaplastic thyroid carcinoma (n = 10), follicular thyroid carcinoma (n = 18), Hürthle cell carcinoma (n = 18), and medullary thyroid carcinoma (n = 10). Only focal positivity was observed in three Hürthle cell carcinoma cases.

CONCLUSION

TROP2 was a helpful marker for differentiating PTC, especially in the classic, tall cell, hobnail, and Warthin-like variants, benign and non-neoplastic lesions, and other neoplasms of the thyroid.

Advances in Trop2-targeted therapy: Novel agents and opportunities beyond breast cancer

Trop2 is a transmembrane glycoprotein and calcium signal transducer with limited expression in normal human tissues. It is consistently overexpressed in a variety of malignant tumors and participates in several oncogenic signaling pathways that lead to tumor development, invasion, and metastasis. As a result, Trop2 has become an attractive therapeutic target in cancer treatment. The anti-Trop2 antibody-drug conjugate (Trodelvy™, sacituzumab govitecan) has been approved to treat metastatic triple-negative breast cancer. However, it is still unclear whether the success observed in Trop2-positive breast cancer could be replicated in other tumor types, owing to the differences in the expression levels and functions of Trop2 across cancer types. In this review, we summarize the recent progress on the structures and functions of Trop2 and highlight the potential diagnostic and therapeutic value of Trop2 beyond breast cancer. In addition, the promising novel Trop2-targeted agents in the clinic were discussed, which will likely alter the therapeutic landscape of Trop2-positive tumors in the future.

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.

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.

Whole-Slide Imaging: Updates and Applications in Papillary Thyroid Carcinoma

Whole-slide imaging (WSI) has wide spectrum of application in histopathology, especially in the study of cancer including papillary thyroid carcinoma. The main applications of WSI system include research, teaching, and assessment and recently pathology practices. The other major advantages of WSI over histological sections on glass slides are easier storage and sharing of information as well as adaptation of use in artificial intelligence. The applications of WSI depend on factors such as volume of services requiring WSI, physical factors (computer server, bandwidth limitation of networks, storages requirements for data), adaption of the WSI images with the laboratory workflow, personnel (IT expert, pathologist, technicians) adaptation to the WSI workflow, validation studies, ethics, and cost efficiency of the application(s).

Recent advances in trophoblast cell-surface antigen 2 targeted therapy for solid tumors

Trophoblast cell-surface antigen 2 (Trop 2) is a transmembrane glycoprotein that is highly expressed in various cancer types with relatively low or no baseline expression in most normal tissues. Its overexpression is associated with tumor growth and poor prognosis; Trop 2 is, therefore, an ideal therapeutic target for epithelial cancers. Several Trop 2 targeted therapeutics have recently been developed for the treatment of cancers, such as anti-Trop 2 antibodies and antibody-drug conjugates (ADCs), as well as Trop 2-specific cell therapy. In particular, the safety and clinical benefit of Trop 2-based ADCs have been demonstrated in clinical trials across multiple tumor types, including those with limited treatment options, such as triple-negative breast cancer, platinum-resistant urothelial cancer, and heavily pretreated non-small cell lung cancer. In this review, we elaborate on recent advances in Trop 2 targeted modalities and provide an overview of novel insights for future developments in this field.

Biomarker analyses in the phase III ASCENT study of sacituzumab govitecan versus chemotherapy in patients with metastatic triple-negative breast cancer

BACKGROUND

The pivotal phase III ASCENT trial demonstrated improved survival outcomes associated with sacituzumab govitecan (SG), an anti-trophoblast cell-surface antigen 2 (anti-Trop-2) antibody-drug conjugate linked with the topoisomerase-inhibitor SN-38, over single-agent chemotherapy treatment of physician's choice (TPC) in previously treated metastatic triple-negative breast cancer (mTNBC). This prespecified, exploratory biomarker analysis from the ASCENT trial evaluates the association between tumor Trop-2 expression and germline BRCA1/2 mutation status with clinical outcomes.

PATIENTS AND METHODS

Patients with mTNBC refractory to or progressing after two or more prior chemotherapies, with one or more in the metastatic setting, were randomized to receive SG (10 mg/kg intravenously days 1 and 8, every 21 days) or TPC (capecitabine, eribulin, vinorelbine, or gemcitabine) until disease progression/unacceptable toxicity. Biopsy or surgical specimens were collected at study entry to determine Trop-2 expression level using a validated immunohistochemistry assay and histochemical scoring. Germline BRCA1/2 mutation status was collected at baseline.

RESULTS

Of 468 assessable patients, 290 had Trop-2 expression data [64% (n = 151 SG) versus 60% (n = 139 TPC)] and 292 had known BRCA1/2 mutation status [63% (n = 149 SG) versus 61% (n = 143 TPC)]. Median progression-free survival in SG- versus TPC-treated patients was 6.9, 5.6, and 2.7 months versus 2.5, 2.2, and 1.6 months for high, medium, and low Trop-2 expression, respectively. Median overall survival (14.2, 14.9, and 9.3 months versus 6.9, 6.9, and 7.6 months) and objective response rates (44%, 38%, and 22% versus 1%, 11%, and 6%) were numerically higher with SG versus TPC in patients with high, medium, and low Trop-2 expression, respectively. Efficacy outcomes were numerically higher with SG versus TPC in patients with and without germline BRCA1/2 mutations.

CONCLUSIONS

SG benefits patients with previously treated mTNBC expressing high/medium Trop-2 compared with standard-of-care chemotherapy and regardless of germline BRCA1/2 mutation status. The small number of patients with low Trop-2 expression precludes definitive conclusions on the benefit of SG in this subgroup.

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.

An affordable immunohistochemical approach to estimate the prevalence of BRAFV600E in large cohort studies-establishing the baseline rate of BRAF mutation in an institutional series of papillary thyroid carcinoma from Thailand

Background

Papillary thyroid carcinoma (PTC) accounts for the majority of diagnoses of thyroid carcinoma. BRAF^V600E mutation is the most common genetic alteration in PTC, which has diagnostic and prognostic significance. The rate of BRAF^V600E mutation in PTC from Thailand has not been reported. Our purpose was to estimate the prevalence of BRAF mutation in a large institutional series using an affordable approach, which combined mutation-specific immunohistochemistry (IHC) with VE1 antibody and tissue microarray (TMA).

Methods

A total of 476 PTC cases plotted on TMA were employed for determining the mutation status in this study. The cancer tissue of initial 100 cases (pilot study) were analyzed for BRAF^V600E mutation by using both direct sequencing and VE1 immunostaining. For the subsequent PTC cases, VE1 IHC was used as an alternative to direct sequencing for the detection of mutation. Univariate and multivariate analyses were done to determine the association of clinicopathological variables with BRAF^V600E mutation.

Results

In the pilot study, VE1 IHC showed excellent analytical performance (κ=0.884) for detecting BRAF^V600E mutation in PTC TMA as compared to direct sequencing. The prevalence of BRAF^V600E in the whole cohort was 60.9% by using VE1 IHC. The mutation was commonly seen in tall cell (92.9%) and classic (70.2%) variants of PTC. Multivariate analysis (P<0.05) showed association of BRAF^V600E with histological type of tumor, extrathyroidal extension, and absence of Hashimoto's thyroiditis.

Conclusions

In conclusion, BRAF^V600E mutation was detected in 60.9% of Thai PTC and it was associated with several aggressive clinicopathological variables of thyroid cancer. VE1 IHC proved as a reliable method able to replace direct sequencing for detection of the mutation. A combination of mutation-specific IHC and TMA allows conducting large cohort studies more labor-saving and cost-efficiently.

Impact of image analysis and artificial intelligence in thyroid pathology, with particular reference to cytological aspects

OBJECTIVE

Thyroid pathology has great potential for automated/artificial intelligence algorithm application as the incidence of thyroid nodules is increasing and the indeterminate interpretation rate of fine-needle aspiration remains relatively high. The aim of the study is to review the published literature on automated image analysis and artificial intelligence applications to thyroid pathology with whole-slide imaging.

METHODS

Systematic search was carried out in electronic databases. Studies dealing with thyroid pathology and use of automated algorithms applied to whole-slide imaging were included. Quality of studies was assessed with a modified QUADAS-2 tool.

RESULTS

Of 919 retrieved articles, 19 were included. The main themes addressed were the comparison of automated assessment of immunohistochemical staining with manual pathologist's assessment, quantification of differences in cellular and nuclear parameters among tumour entities, and discrimination between benign and malignant nodules. Correlation coefficients with manual assessment were higher than 0.76 and diagnostic performance of automated models was comparable with an expert pathologist diagnosis. Computational difficulties were related to the large size of whole-slide images.

CONCLUSIONS

Overall, the results are promising and it is likely that, with the resolution of technical issues, the application of automated algorithms in thyroid pathology will increase and be adopted following suitable validation studies.

Evaluation of Diagnostic Utility of Immunohistochemistry Markers of TROP-2 and HBME-1 in the Diagnosis of Thyroid Carcinoma

OBJECTIVE

The diagnosis of thyroid tumors is based on histologic features, but the distinction between benign and malignant thyroid lesions is somehow difficult, especially in lesions with a follicular pattern. Thus, ancillary studies, such as immunohistochemistry (IHC), may be helpful. In this study, we aimed to evaluate the diagnostic value of 2 IHC markers, TROP-2 and HBME-1, in the diagnosis of thyroid cancers.

STUDY DESIGN

A total of 102 cases of thyroid lesions, including papillary thyroid carcinoma (classic variant) (29 cases), follicular variant of papillary thyroid carcinoma (21 cases), multinodular goiter (22 cases), follicular adenoma (24 cases), and follicular carcinoma (6 cases) were selected. The hematoxylin-eosin slides were reviewed for confirmation of diagnosis, and IHC examination for TROP-2 and HBME-1 was performed.

RESULT

HBME-1 had 84% sensitivity and 98% specificity with a positive predictive value (PPV) of 98% and a negative predictive value (NPV) of 83%. TROP-2 had 93% sensitivity and 74% specificity with a PPV of 81% and an NPV of 90% in malignant thyroid lesions.

CONCLUSION

IHC panel consisting of TROP-2 and HBME-1 can be used in equivocal follicular patterned lesions for the diagnosis of thyroid carcinomas.

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.

The diagnostic value of TROP-2, SLP-2 and CD56 expression in papillary thyroid carcinoma

OBJECTIVE

The study aimed to explore some novel diagnostic biomarkers for papillary thyroid carcinoma (PTC) by identifying the different expression of TROP-2, SLP-2 and CD56 in benign and malignant thyroid lesions.

METHODS

We evaluated the mRNA expressions of TROP-2 and SLP-2 in fine needle aspirates (FNAs) which contained 10 PTCs and 10 benign follicular adenomas (FAs) using quantitative real-time PCR (qRT-PCR). Immunohistochemical (IHC) staining of TROP-2, SLP-2 and CD56 was also performed on postoperative samples of 30 PTCs and 29 FAs. Membranous or cytoplasmic staining in > 10% of cells was considered as positive. Diagnostic sensitivity, specificity, positive predictive value, negative predictive value (NPV) and diagnostic accuracy of these three biomarkers were carried out. We further analyzed the associations between the clinical features and the expressions of markers in PTCs.

RESULTS

The mRNA expressions of both TROP-2 and SLP-2 were increased substantially in PTCs in comparison with those in FAs (P < 0.05). Similarly, IHC for these two proteins demonstrated higher positive staining in PTCs than in FAs (96.5% vs. 12.5% for TROP-2, 83.3% vs. 20.7% for SLP-2, P < 0.05). Conversely, CD56 expression was lost with 86.7% of PTCs. In identifying malignancy, TROP-2 was the most sensitive marker and CD56 was the most specific one. When the markers were combined, the sensitivity and NPV increased to 100% and had better diagnostic accuracy. However, no association was found between biomarker expressions and clinicopathological factors in PTCs.

CONCLUSIONS

We found that TROP-2, SLP-2 and CD56 were effective diagnostic markers for PTC, especially when they were combined to use.

HBME-1 expression in differentiated thyroid carcinoma and its correlation with the ultrasonic manifestation of thyroid

We investigated expression of the protein human bone marrow endothelial cell marker-1 (HBME-1) in differentiated thyroid carcinoma tissues, and analyzed its correlation with ultrasonic manifestation of thyroid. The immunohistochemistry (IHC) staining method was used to measure the expression of HBME-1 in patient with nodular goiter (control group), papillary differentiated thyroid carcinoma (papillary carcinoma group) and follicular differentiated thyroid carcinoma (follicular carcinoma group) to investigate the differences in expression of HBME-1. We further analyzed the correlation of the expression of HBME-1 in the papillary carcinoma group and the follicular carcinoma group with ultrasonic manifestation of thyroid. In both the papillary carcinoma group and the follicular carcinoma group, the levels of HBME-1 in affected tissues and the IHS score of HBME-1 expression were higher than those in the control group (p<0.05). In the papillary carcinoma group, the mean IHS score of HBME-1 expression in affected tissues was higher than in the follicular carcinoma group (p<0.05). There were no statistically significant differences in comparison to HBME-1 expression in affected tissues between the papillary carcinoma group and the follicular carcinoma group (p>0.05). Between the papillary carcinoma group and the follicular carcinoma group, the differences in the comparison of the nodule diameter, echo, shape, boundary, calcification and blood flow signal were statistically significant (p<0.05), but incidence rate of enlargement of cervical lymph nodules between the groups were not statistically significant (p>0.05). Among patients in the papillary carcinoma group, the comparison of the nodule diameter, echo, shape, boundary, calcification and blood flow signal between the HBME-1-positive patients and the HBME-1-negative patients showed no statistical significance (p>0.05), but in the nodules of HBME-1-positive patients, the proportion of blood flow signal was higher than that in the nodules of HBME-1-negative patients. Among patients in the follicular carcinoma group, there was no statistically significant differences in the comparison of ultrasonic manifestation of thyroid (p>0.05). Therefore, there are difference in HBME-1 expression and ultrasonic manifestations of thyroid in patients with papillary carcinoma and follicular differentiated thyroid carcinoma.

Current Status of Thyroid Fine-Needle Aspiration Practice in Thailand

Thyroid carcinoma is one of the leading malignancies in Thailand increasingly prevalent in the female population. Fine-needle aspiration (FNA) cytology is a widely used diagnostic tool for evaluation of thyroid nodules and thyroid cancer. Thyroid FNA is a routine procedure universally performed in Thai hospitals by a variety of clinical specialists. Manual guidance is the first-line choice complemented by ultrasound assistance in selected cases. Despite national guidelines recommendations, the diagnostic criteria and terminology of the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) was slowly adopted in the local settings. Currently, the Bethesda system is actively promoted by the local professional societies as a uniform reporting system. Experience with thyroid FNA has been rarely reported to date-only a handful of publications are available in local journals. Our review, in addition to presenting various aspects of thyroid FNA in Thailand, established for the first time national references for a certain statistical outputs of TBSRTC based on the original multi-institutional cohort. The risk of malignancy in 2,017 operated thyroid nodules collected from three tertiary thyroid cancer centers was 21.7%, 14.7%, 35.9%, 44.4%, 76.7%, and 92.6% for categories I to VI, respectively. The malignancy risk in several diagnostic categories (II to IV) was higher than the risk estimated by TBSRTC and recent meta-analysis studies. We endorse the use of uniform terminology of the Bethesda system in Thailand, which will help facilitate communication among diverse medical professionals involved in the management of patients with thyroid nodules, to share local experience with the international audience.

Aberrant expression of CD20 in thyroid cancer and its clinicopathologic significance

CD20 is the first-line diagnostic marker of B-cells, which serves as the target of the therapeutic monoclonal antibodies in B-cell lymphomas and leukemias. Recently, aberrant CD20 expression has been described in a small series of papillary thyroid carcinomas (PTCs). We aimed to evaluate CD20 immunoexpression and to perform clinicopathologic correlation in a large set of thyroid tumors, including a cohort of high-grade thyroid cancer. A total of 625 cases of thyroid tumor comprised tissue microarrays of 538 PTCs and 47 follicular adenomas, and whole-slide sections of 40 aggressive thyroid carcinomas (10 radioiodine-refractory PTCs and 8 poorly differentiated, 5 anaplastic, and 17 medullary thyroid carcinomas) were immunostained with anti-CD20 monoclonal antibody. BRAF^V600E mutation was tested by direct sequencing in 478 cancers. Our study found that a small subset of PTCs (<10%, mainly of classic variant) exhibited aberrant membranous expression of CD20. These tumors displayed less aggressive histological features and had a lower prevalence of BRAF^V600E mutation. We also discovered that CD20 expression was maintained in 6%-20% of aggressive thyroid cancers but not observed in follicular adenomas. All CD20-positive tumor cells were negative for CD79a and PAX5. Aberrant expression of CD20 by thyroid cancer cells may present a diagnostic pitfall in cytologic evaluation of thyroid and cervical masses. Residual expression of CD20 in aggressive cancers may offer promise for translational implications, which merits further experimental investigation.

PSMA expression by microvasculature of thyroid tumors - Potential implications for PSMA theranostics

Prostate-specific membrane antigen (PSMA) is overexpressed in prostate cancer epithelium, making it a promising target for molecular imaging and therapy. Recently, several studies found unexpected PSMA radiotracer uptake by thyroid tumors, including radioiodine-refractory (RAIR) cancers. PSMA expression was reported in tumor-associated endothelium of various malignancies, however it has not been systematically addressed in thyroid tumors. We found that PSMA was frequently expressed in microvessels of thyroid tumors (120/267), but not in benign thyroid tissue. PSMA expression in neovasculature was highly irregular ranging from 19% in benign tumors to over 50% in thyroid cancer. Such heterogeneity was not directly attributed to endothelial cell proliferation as confirmed by immunostaining with proliferation-associated endothelial marker CD105. PSMA expression was associated with tumor size (p = 0.02) and vascular invasion in follicular carcinoma (p = 0.03), but not with other baseline histological, and clinical parameters. Significant translational implication is that RAIR tumors and high-grade cancers maintain high level of PSMA expression, and can be targeted by PSMA ligand radiopharmaceuticals. Our study predicts several pitfalls potentially associated with PSMA imaging of the thyroid, such as low expression in oncocytic tumors, absence of organ specificity, and PSMA-positivity in dendritic cells of chronic thyroiditis, which is described for the first time.