Andrey Bychkov

The FOXE1 and NKX2-1 loci are associated with susceptibility to papillary thyroid carcinoma in the Japanese population

Background FOXE1 and NKX2-1 are two known genetic risk factors for the predisposition to sporadic papillary thyroid carcinoma (PTC) in Europeans, but their association in other ethnicities is still unknown. Objective We aim to examine the association of the two genes with Japanese sporadic PTC, which exhibits high BRAFV600E mutation rate. Methods 507 Japanese sporadic PTC cases and 2766 controls were genotyped for rs965513 (FOXE1) and rs944289 (NKX2-1). PTC cases were also examined for their BRAFV600E mutational status. Results The association of both rs965513 (p=1.27×10−4, OR=1.69, 95% CI 1.29 to 2.21) and rs944289 (p=0.0121, OR=1.21, 95% CI 1.04 to 1.39) with the risk of sporadic PTC was confirmed. Subgroup analysis based on the BRAF mutational status showed strong association of rs965513 with BRAFV600E-positive cases (p=2.26×10−4, OR=1.72, 95% CI 1.29 to 2.29), but not with BRAFV600E-negative cases (p=0.143, OR=1.52, 95% CI 0.87 to 2.65). However, there was no difference in the observed effect size between both subgroups. For rs944289, both subgroups showed marginal association (p=0.0585, OR=1.17, 95% CI 0.99 to 1.37 for BRAFV600E-positive cases; p=0.0492, OR=1.35, 95% CI 1.00 to 1.81 for BRAFV600E-negative cases). Conclusions Both FOXE1 and NKX2-1 were associated with the increased risk of sporadic Japanese PTC. No clear associations were observed for either SNP with BRAFV600E status.

Low Rate of Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features in Asian Practice

Th is p ap er h as b ee n pe er -r ev ie w ed a nd a cc ep te d fo r p ub lic at io n, b ut h as y et to u nd er go c op ye di tin g an d pr oo f c or re ct io n. T he fi na l p ub lis he d ve rs io n m ay d iff er fr om th is p ro of . Low rate of NIFTP in Asian practice Andrey Bychkov, Mitsuyoshi Hirokawa, Chan Kwon Jung, Zhiyan Liu, Yun Zhu, SoonWon Hong, Shinya Satoh, Chiung‐Ru Lai, Lien Huynh, Kennichi Kakudo Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand Department of Diagnostic Pathology and Cytology, Kuma Hospital, Kobe, Japan Department of Hospital Pathology, College of Medicine, The Catholic University of Korea, Seoul, South Korea Department of Pathology, Shandong University School of Medicine, Shandong, China Department of Pathology, Jiangsu Institution of Nuclear Medicine, Wuxi, Jiangsu Province, China Department of Pathology, Yonsei University, College of Medicine, Seoul, South Korea Department of Endocrine Surgery, Yamashita Thyroid and Parathyroid Clinic, Fukuoka, Japan Department of Pathology, Taipei Veterans General Hospital, Taipei, Taiwan Department of Pathology, Da Nang Hospital, Danang, Vietnam Department of Pathology, Nara Hospital, Kindai University Faculty of Medicine, Nara, Japan Author information Andrey Bychkov, MD, PhD Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; andrey.b@chula.ac.th Mitsuyoshi Hirokawa, MD, PhD Department of Diagnostic Pathology and Cytology, Kuma Hospital, Kobe, Japan; mhirokawa@kuma‐h.or.jp Chan Kwon Jung, MD, PhD Department of Hospital Pathology, College of Medicine, The Catholic University of Korea, T hy ro id

The Common Genetic Variant rs944289 on Chromosome 14q13.3 Associates with Risk of Both Malignant and Benign Thyroid Tumors in the Japanese Population

BACKGROUND Several single nucleotide polymorphisms (SNP) have been identified to be associated with the risk for differentiated thyroid cancer in populations of distinct ethnic background. The relationship of these genetic markers to a benign tumor of the thyroid, follicular adenoma (FA), is not well established. METHODS In a multicenter retrospective case-control study, five thyroid cancer-related SNPs-rs966513 (9q22.33, FOXE1), rs944289 (14q13.3, PTCSC3), rs2439302 (8p12, NRG1), rs1867277 (9q22.23, FOXE1), and rs6983267 (8q24, POU5F1B)-were genotyped in 959 cases of histologically verified FA, 535 papillary thyroid carcinomas (PTC), and 2766 population controls. RESULTS A significant association was found between FA and rs944289 (p=0.002; OR 1.176 [CI 1.064-1.316]), and suggestively with rs2439302 (p=0.033; OR 1.149 [CI 1.010-1.315]). In PTC, significant associations were confirmed for rs965513 (p=4.21E-04; OR 1.587 [CI 1.235-2.000]) and rs944289 (p=0.003; OR 1.234 [CI 1.075-1.408]), newly found for rs2439302 (p=0.003; OR 1.266 [CI 1.087-1.493]) and rs1867277 (p=1.17E-04; OR 1.492 [CI 1.235-1.818]), and was not replicated for rs6983267 (p=0.082; OR 1.136 [CI 0.980-1.316]) in this series. A significant correlation between rs2439302 genotype and relative expression of NRG1 was detected in normal and tumor counterparts of PTC (about 10% decrease per each risk allele). NRG1 expression also significantly correlated with that of PTCSC3. CONCLUSIONS Association of rs944289, which was previously known to confer risk for thyroid cancer, with FA, and the correlation between PTCSC3 and NRG1 expression demonstrates that predisposing genetic factors are partly common for benign and malignant thyroid tumors, and imply broader roles of the pathways they underlie in thyroid tumorigenesis, not limited to carcinogenesis.

Thyroid FNA cytology in Asian practice—Active surveillance for indeterminate thyroid nodules reduces overtreatment of thyroid carcinomas

Although Asian thyroid practices have implemented the American Thyroid Association guidelines, significant deviations in actual risk of malignancy (ROM) have been reported. With review of the literature from Asia, the authors examine the underlining reasons for actual ROMs reported in Asia being so different from western practice based on the authors perspective. Although the most popular diagnostic system for thyroid cytology used in Asian countries is the Bethesda system, the Japan Thyroid Association published clinical guidelines, including a national reporting system for thyroid cytology, to adapt conservative clinical management (active surveillance and strict triage patients for surgery) for low‐risk thyroid carcinomas. As less aggressive clinical management is favoured in Asian societies, strict triage of patients with indeterminate thyroid nodules for surgery is usually applied, which ultimately reduces overtreatment of indolent thyroid tumours. As a result, low resection rates and high ROMs for indeterminate nodules were achieved in Asian practices using the same Bethesda system. Recently, borderline thyroid tumours were introduced in the thyroid tumour classification and significant decreases in ROMs have been reported in the indeterminate categories in western practice. However, ROM of indeterminate nodules remained high in Asian practice even after borderline tumours were deemed benign. These results suggested that the diagnostic threshold of papillary thyroid carcinoma‐type nuclear features varied among practices (stricter in Asia than in western practice), and diagnostic surgery was not performed for a significant number of indeterminate nodules with benign clinical features in Asian practice, resulting in low rates of borderline tumours in surgically‐treated patients.

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

We aimed to evaluate the diagnostic utility of the novel immunohistochemical marker TROP-2 on thyroid specimens (226 tumours and 207 controls). Whole slide immunohistochemistry was performed and scored by automated digital image analysis. Non-neoplastic thyroid, follicular adenomas, follicular carcinomas, and medullary carcinomas were negative for TROP-2 immunostaining. The majority of papillary thyroid carcinoma (PTC) specimens (94/114, 82.5%) were positive for TROP-2; however, the pattern of staining differed significantly between the histopathological variants. All papillary microcarcinomas (mPTC), PTC classic variant (PTC cv), and tall cell variant (PTC tcv) were TROP-2 positive, with mainly diffuse staining. In contrast, less than half of the PTC follicular variant specimens were positive for TROP-2, with only focal immunoreactivity. TROP-2 could identify PTC cv with 98.1% sensitivity and 97.5% specificity. ROC curve analysis found that the presence of >10% of TROP-2 positive cells in a tumour supported a diagnosis of PTC. The study of intratumoural heterogeneity showed that low-volume cytological samples of PTC cv could be adequately assessed by TROP-2 immunostaining. The TROP-2 H-score (intensity multiplied by proportion) was significantly associated with PTC variant and capsular invasion in encapsulated PTC follicular variant (p<0.001). None of the baseline (age, gender) and clinical (tumour size, nodal disease, stage) parameters were correlated with TROP-2 expression. In conclusion, TROP-2 membranous staining is a very sensitive and specific marker for PTC cv, PTC tcv, and mPTC, with high overall specificity for PTC.

Thyrotropin Signaling Confers More Aggressive Features with Higher Genomic Instability on BRAFV600E-Induced Thyroid Tumors in a Mouse Model

BACKGROUND The BRAF(V600E) mutation is the most common genetic alteration in papillary thyroid carcinomas (PTCs). Transgenic mice overexpressing BRAF(V600E) in their thyroids under control of the thyroglobulin promoter (Tg-BRAF2 mice) developed invasive PTCs with high penetrance. However, these mice showed elevated thyrotropin (TSH) levels, which also stimulate the proliferation of thyrocytes and tumorigenesis. The purpose of the present study was to investigate how TSH signaling cooperates with BRAF(V600E) in the process of thyroid carcinogenesis. METHODS We crossed Tg-BRAF2 mice with TSH receptor knockout (TshR(-/-)) mice. Four genetically distinct mice groups-Braf(wt)/TshR(+/-) (group 1), Braf(wt)/TshR(-/-) (group 2), Tg-BRAF2/TshR(+/-) (group 3), and Tg-BRAF2/TshR(-/-) (group 4)--were sacrificed at 12 and 24 weeks of age. We performed histopathological analysis. Genomic instability was evaluated by immunofluorescence for p53-binding protein 1 (53BP1) and γH2AX. Invasiveness and genomic instability were also evaluated using thyroid PCCL3 cells expressing BRAF(V600E). RESULTS Groups 3 and 4 developed distinct neoplasias comparable to human PTCs. Group 3 developed typically larger, more aggressive, invasive tumors compared to group 4. The frequency of 53BP1 and γH2AX foci-indicators of genomic instability--in group 3 was higher than that in group 4. TSH also enhanced invasiveness and genomic instability in PCCL3 cells with BRAF(V600E) expression. CONCLUSIONS These data demonstrate that the TSH signaling confers more aggressive features in BRAF(V600E)-induced thyroid tumors in mice. This might be due, in part, to accelerated genomic instability.

Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features in Asian Practice: Perspectives for Surgical Pathology and Cytopathology

The introduction of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was initiated and promoted by pathologists. Recent Asian studies added new knowledge to the existing literature to aid a better understanding of NIFTP. Our original data and the results of a meta-analysis suggest that the initial rate of NIFTP has been overestimated, averaging 9.1% (95% confidence interval [CI] 6.0–12.7%) of all papillary thyroid cancers worldwide. The incidence of NIFTP in the Asian population (1.6%, 95% CI 0.9–2.5%; 7 studies) is significantly lower than that reported in the non-Asian series (13.3%, 95% CI 9.0–18.3%; 18 studies). Such difference could be attributed to various perceptions of histological diagnostic thresholds, different nature of papillary thyroid carcinoma, and different approaches in the management of thyroid nodules. The active surveillance for indeterminate nodules and NIFTP, largely represented in the indeterminate cytologic categories, promoted by Japanese institutions establishes a new paradigm to reduce overtreatment of these patients. The lower prevalence of NIFTP in the Asian series indicates a low impact on the risk of malignancy in cytopathology, as it was demonstrated in our original multi-institutional cohort of thyroid nodules, and may predict a low impact on the performance of commercial molecular tests. Several Korean studies addressed the issue of BRAF mutation in NIFTP, which prompted the current refinement of the diagnostic criteria for NIFTP. Our survey of Asian pathologists found that the term NIFTP has not been universally adopted in the local practice. Endocrine pathologists must promote the new entity through provision of educational activities.

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.

Current Practices of Thyroid Fine-Needle Aspiration in Asia: A Missing Voice

© 2017 The Korean Society of Pathologists/The Korean Society for Cytopathology This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. pISSN 2383-7837 eISSN 2383-7845 Current Practices of Thyroid Fine-Needle Aspiration in Asia: A Missing Voice

The Use of Fine-Needle Aspiration (FNA) Cytology in Patients with Thyroid Nodules in Asia: A Brief Overview of Studies from the Working Group of Asian Thyroid FNA Cytology

Ultrasound-guided fine-needle aspiration (FNA) cytology is the most widely used screening and diagnostic method for thyroid nodules. Although Western guidelines for managing thyroid nodules and the Bethesda System for Reporting Thyroid Cytopathology are widely available throughout Asia, the clinical practices in Asia vary from those of Western countries. Accordingly, the Working Group of Asian Thyroid FNA Cytology encouraged group members to publish their works jointly with the same topic. The articles in this special issue focused on the history of thyroid FNA, FNA performers and interpreters, training programs of cytopathologists and cytotechnicians, staining methods, the reporting system of thyroid FNA, quality assurance programs, ancillary testing, and literature review of their own country’s products. Herein, we provide a brief overview of thyroid FNA practices in China, India, Japan, Korea, the Philippines, Taiwan, and Thailand.