Update on the cytologic features of papillary thyroid carcinoma variants

Macrofollicular Architecture in Invasive Encapsulated Follicular Variant of Papillary Thyroid Carcinoma: A Pitfall in Thyroid Practice

BACKGROUND

Predominantly macrofollicular architecture in invasive encapsulated follicular variant of papillary thyroid carcinoma (IEFVPTC-MF) is rare and often a cause of misinterpretation during pre-operative work-up and histopathology evaluation. We comprehensively evaluated the radiological, cytological, gross, microscopic, molecular and follow-up characteristics of four such cases, intending to increase its recognition and add our experience to the limited literature available.

METHODS

All such histopathologically-proven cases of IEFVPTC-MF were retrieved from the departmental archives. The clinical details, thyroid ultrasound, cytology and thyroid scan findings were reviewed. Allele-specific PCR for BRAF p.V600E, KRAS, NRAS, and HRAS mutations, and FISH assays for ETV6::NTRK3 fusion and RET fusions were performed.

RESULTS

There were four cases of IEFVPTC-MF diagnosed between 2021 and 2022, involving two males and two females. The median age at presentation was 27 years, and the duration of the disease was 1-10 years. Thyroid ultrasound was TR1 (benign; n = 1), TR2 (not suspicious; n = 2), or TR4 (moderately suspicious; n = 1). Cytology was categorized as nondiagnostic (n = 1), benign (n = 1), and atypia of undetermined significance (n = 1). The three nodules with available cytology smears showed abundant colloid. Cells were arranged as sheets/microfollicles/clusters. Nuclei were predominantly round with minimal/focal elongation, membrane irregularity, and cellular crowding. On gross examination, cut surfaces of the tumors showed variable amounts of colloid. The tumors were solid-cystic. Histopathology revealed partially encapsulated multinodular tumors. There were prominent pseudopapillae projecting into the lumina of macrofollicles. Nuclei were predominantly round with variable nuclear atypia, including chromatin clearing and multifocal presence of nuclear grooves. Pseudoinclusions were identified in two. Molecular analysis revealed NRAS codon 61 mutation and ETV6::NTRK3 fusion in one case each. Two patients had cervical lymph node and hematogenous metastases. Post-radio-active iodine, the response was structurally incomplete (n = 2), indeterminate (n = 1) and excellent (n = 1).

CONCLUSIONS

Macrofollicular architecture in invasive encapsulated follicular variant of papillary thyroid carcinoma is a major pitfall in thyroid oncology practice. Long-standing disease, and ultrasonographic and cytological features that overlap with benign disease, often lead to underdiagnosis during pre-operative evaluation. As patients may consequently develop distant metastases and have inadequate treatment response, there is a need for more vigilant understanding of the spectrum of macrofollicular thyroid disease for accurate diagnosis. ETV6::NTRK3 or other fusions, when found, present opportunities for targeted therapy.

Advances and challenges in thyroid cancer: The interplay of genetic modulators, targeted therapies, and AI-driven approaches

Thyroid cancer continues to exhibit a rising incidence globally, predominantly affecting women. Despite stable mortality rates, the unique characteristics of thyroid carcinoma warrant a distinct approach. Differentiated thyroid cancer, comprising most cases, is effectively managed through standard treatments such as thyroidectomy and radioiodine therapy. However, rarer variants, including anaplastic thyroid carcinoma, necessitate specialized interventions, often employing targeted therapies. Although these drugs focus on symptom management, they are not curative. This review delves into the fundamental modulators of thyroid cancers, encompassing genetic, epigenetic, and non-coding RNA factors while exploring their intricate interplay and influence. Epigenetic modifications directly affect the expression of causal genes, while long non-coding RNAs impact the function and expression of micro-RNAs, culminating in tumorigenesis. Additionally, this article provides a concise overview of the advantages and disadvantages associated with pharmacological and non-pharmacological therapeutic interventions in thyroid cancer. Furthermore, with technological advancements, integrating modern software and computing into healthcare and medical practices has become increasingly prevalent. Artificial intelligence and machine learning techniques hold the potential to predict treatment outcomes, analyze data, and develop personalized therapeutic approaches catering to patient specificity. In thyroid cancer, cutting-edge machine learning and deep learning technologies analyze factors such as ultrasonography results for tumor textures and biopsy samples from fine needle aspirations, paving the way for a more accurate and effective therapeutic landscape in the near future.

The Correlation between Proliferative Immunohistochemical Markers and Papillary Thyroid Carcinoma Aggressiveness

Background and Objectives: Papillary thyroid carcinoma (PTC) is one of the most common malignancies of the endocrine system. In order to improve the ability to predict tumor behavior, several studies have been conducted to search for surrogate prognostic immunohistochemical tumor markers. Objective: To evaluate the correlation between the intensity of different immunohistochemical marker staining in PTC and the risk for extrathyroidal extension and metastases. Materials and Methods: The study comprised patients who underwent hemi- or total thyroidectomy. Thyroid tissues were immunohistochemically stained for different tumor proliferative markers: Minichromosome maintenance proteins 2 (MCM2), Ki-67 labeling index, E-Cadherin, Neuropilin-1 and Metallothionein. The correlation between the intensity of each marker staining and the final diagnosis (benign neoplasm and PTC) and the correlation between the intensity of each staining and tumor extrathyroidal extension and metastases were evaluated. Results: The study included 66 patients. Staining for Metallothionein, E-Cadherin and MCM2 significantly differed between benign neoplasm (n = 22) and thyroid-confined PTC (n = 21) (p = 0.002, 0.004 and 0.005, respectively), between benign neoplasm and PTC with extrathyroidal extension (n = 11) (p = 0.001, 0.006 and 0.01, respectively), and between benign neoplasm and PTC with metastases (n = 12) (p = 0.01, <0.001 and 0.037, respectively). No staining correlated with extrathyroidal extension. The intensity of E-Cadherin staining was significantly lower in PTC with metastases than thyroid confined PTC and PTC with extrathyroidal extension (p = 0.028 and 0.021, respectively). Conclusions: Immunohistochemical staining for Metallothionein, E-Cadherin and MCM2 significantly distinguished between benign thyroid tumor and PTC. E-Cadherin staining significantly and inversely correlated with the presence of metastases.

A new molecular subclassification and in silico predictions for diagnosis and prognosis of papillary thyroid cancer by alternative splicing profile

Introduction: Papillary thyroid cancer (PTC) is the most common endocrine malignancy. However, different PTC variants reveal high heterogeneity at histological, cytological, molecular and clinicopathological levels, which complicates the precise diagnosis and management of PTC. Alternative splicing (AS) has been reported to be potential cancer biomarkers and therapeutic targets. Method: Here, we aim to find a more sophisticated molecular subclassification and characterization for PTC by integrating AS profiling. Based on six differentially expressed alternative splicing (DEAS) events, a new molecular subclassification was proposed to reclassify PTC into three new groups named as Cluster0, Cluster1 and Cluster2 respectively. Results: An in silico prediction was performed for accurate recognition of new groups with the average accuracy of 91.2%. Moreover, series of analyses were implemented to explore the differences of clinicopathology, molecular and immune characteristics across them. It suggests that there are remarkable differences among them, but Cluster2 was characterized by poor prognosis, higher immune heterogeneity and more sensitive to anti-PD1 therapy. The splicing correlation networks proved the complicated regulation relationships between AS events and splicing factors (SFs). An independent prognostic indicator for PTC overall survival (OS) was established. Finally, three compounds (orantinib, tyrphostin-AG-1295 and AG-370) were discovered to be the potential therapeutic agents. Discussion: Overall, the six DEAS events are not only potential biomarkers for precise diagnosis of PTC, but also the probable prognostic predictors. This research would be expected to highlight the effect of AS events on PTC characterization and also provide new insights into refining precise subclassification and improving medical therapy for PTC patients.

FN1 Promotes Thyroid Carcinoma Cell Proliferation and Metastasis by Activating the NF-Κb Pathway

BACKGROUND

Thyroid cancer (THCA) is a common endocrine tumor. This study aims to identify the THCA-related key gene Fibronectin 1 (FN1) by bioinformatics methods and explore its function and regulatory mechanism.

METHODS

Gene Expression Omnibus database (GSE3678, GSE33630, and GSE53157 datasets) was searched for the analysis of differentially expressed genes (DEGs) in THCA tissues v.s. (normal tissues). The enrichment of DEGs was investigated by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways using the DAVID database. Screening the hub gene was performed with the STRING database and Cytoscape software. The expression and survival analyses of these hub genes in THCA were studied with the Gene Expression Profiling Interactive Analysis database. LinkedOmics database was searched for the related signaling pathways regulated by FN1 in THCA. Real-time quantitative reverse transcriptase polymerase chain reaction was adopted to detect the mRNA expression of Fibromodulin, microfibril-associated protein 4, Osteoglycin, and FN1. The cell viability, growth, migration and aggressiveness were examined by Cell counting kit-8, 5-Ethynyl-2 '- deoxyuridine assay, scratch assay, and Transwell assay. The expression levels of NF-κB signaling pathway-related proteins (p-IκB-α, p-IKK-β, NF-κB p65) were detected by Western blot.

RESULTS

FN1 mRNA was up-regulated in THCA tissues and cell lines (MDA-T85 and MDA-T41). The high expression of FN1 is relevant to larger tumor diameters and lymph node metastasis in sufferers with THCA. Functional experiments showed that overexpression of FN1 in the MDA-T85 cell line promoted growth, migration and aggressiveness; knockdown of FN1 in MDA-T41 cells inhibited these malignant behaviors. In mechanism, FN1 promoted the expression levels of proteins related with NF-κB signaling pathway and activated NF-κB signaling pathway.

CONCLUSION

FN1 is up-regulated in THCA and facilitates cell growth, migration and invasion by activating the NF-κB signaling pathway. FN1 will be a promising biomarker of THCA and may become a molecular target for THCA treatment.

Metastatic lung carcinoma in thyroid aspirates: A case series and literature review illustrating diagnostic challenges

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most common primary malignant thyroid neoplasm and malignant diagnosis in thyroid aspirates. Metastatic adenocarcinoma of lung is an under-recognized mimicker which overlaps cytomorphologically and immunocytochemically with PTC. This case series reviews thyroid aspirates of metastatic lung carcinomas, aiming to address the similarities and methods of differentiating this entity from PTC.

METHODS

Thyroid aspirates of metastatic lung carcinomas were obtained by a computerized search. Clinico-cytological features and ancillary test results were reviewed. Literature review was performed for published cases of metastatic lung carcinomas in thyroid aspirates.

RESULTS

A total of 14 cases were found, including nine adenocarcinomas, three TTF1-positive non-small cell lung carcinomas (NSCLCs), one small cell carcinoma and one squamous cell carcinoma. The adenocarcinomas and TTF1-positive NSCLCs displayed PTC-like features including papillae/papillary-like fronds (n=6/12, 50%), nuclear grooves (n=5/12, 41.7%) and inclusions (n=1/12, 8.3%), chromatin clearing (n=3/12, 25%), calcifications (n=3/12, 25%) and multinucleated giant cells (n=2/12, 16.7%). Useful distinguishing features observed were prominent nucleoli, coarse chromatin, mitosis, and necrosis. TTF-1 immunocytochemistry was positive in most cases (n=5/6, 83.3%), while PAX8 and thyroglobulin were consistently negative. EGFR exon 19 deletion was detected on cell block preparation in a single case, corresponding to its lung primary. Literature search yielded 84 cases of metastatic malignancies, with lung carcinomas comprising of 3.6%-33.3% in case series of metastatic malignancies.

CONCLUSION

Metastatic adenocarcinoma of lung and PTC share significant cytomorphological and immunocytochemical similarities. A high degree of caution, meticulous clinico-cytological assessment and prudent use of ancillary techniques is necessary to avoid potential misdiagnosis.

Fine-needle aspiration cytology of metastatic carcinomas with papillary architecture: a systemic assessment of clinical, cytologic and immunohistochemical parameters

BACKGROUND

Papillary structures are frequently encountered in metastatic carcinomas from various organs and tumors of different histotypes. This study aims to investigate the predictive value of fine-needle aspiration cytology (FNAC), immunohistochemistry (IHC) and clinical parameters in assessment of primary sites of metastatic carcinomas with papillary architecture.

METHODS

FNAC of metastatic carcinomas with papillary architecture were evaluated for overall cellularity, epithelial cohesion, background features, architecture of papillae, cytology and IHC. The corresponding clinical information were also reviewed.

RESULTS

Totally 130 cases were included. The most common primaries were thyroid (38.5%), lung (30.8%) and gynecological organs (22.3%) with the remainders being pancreaticobiliary, urothelial, colorectal, and esophageal. Age (p=.039), biopsy site (p<.001) and laterality (p=.006) correlated with primary site. Papillary structures were confirmed on biopsy/excision of most cases (n=85/87, 97.7%). Thyroid primaries demonstrated broad papillary stalks, thin lining epithelium, fewer epithelial polymorphs, and presence of background giant cells and histiocytes (p=.021-<.001). Low-grade cytologic features, nuclear grooves and inclusions (p<.001) were seen in thyroid primaries. High-grade features (p<.001-0.49), multinucleated tumor cells, apoptotic bodies and mitoses (p<.001-0.49) were more common in lung/gynecological primaries. Multivariate analysis identified nuclear/cytoplasmic ratio, chromatin character, presence of nuclear groove and mitosis as independent features (p=0.001-.024). TTF1/TGB/PAX8 panel demonstrated good agreement with cytologic assessment and primary site.

CONCLUSION

Papillary structures and cytologic features are reproducible in FNACs of metastases and corresponding primaries. Cytologic features, IHC and clinical information are invaluable in determining the primary site.

Diagnostic Efficacy of Ultrasound, Cytology, and BRAFV600E Mutation Analysis and Their Combined Use in Thyroid Nodule Screening for Papillary Thyroid Microcarcinoma

Background

Ultrasound, cytology, and BRAF^V600E mutation analysis were applied as valuable tools in the differential diagnosis of thyroid nodules. The aim of the present study was to evaluate the diagnostic efficiency of the three methods and their combined use in screening for papillary thyroid microcarcinoma (PTMC).

Methods

A total of 1,081 patients with 1,157 thyroid nodules (0.5–1 cm in maximum diameter) classified as thyroid imaging reporting and data system (TIRADS) 4–5 were recruited. All patients underwent ultrasound, fine-needle aspiration (FNA) examination, and an additional BRAF^V600E mutation test. TIRADS and Bethesda System for Reporting Thyroid Cytopathology (BSRTC) were adopted to judge the ultrasound and cytological results. The receiver operating characteristic (ROC) curve was established to assess the diagnostic values of different methods.

Results

Of the 1,157 nodules, 587 were benign and 570 were PTMCs. BRAF^V600E mutation test had highest sensitivity (85.4%), specificity (97.1%), accuracy (91.4%), and area under the ROC curve (Az) value (0.913) among the three methods. The combination of BSRTC and BRAF^V600E mutation analysis yielded a considerably high sensitivity (96.0%), accuracy (94.3%), and negative predictive value (95.9%) than either BSRTC or BRAF^V600E mutation alone (P < 0.0001 for all comparisons). Of all the methods, the combined use of the three methods produced the best diagnostic performance (Az = 0.967), which was significantly higher than that (Az = 0.943) for the combination of BSRTC and BRAF^V600E mutation (P < 0.0001). The diagnostic accuracy of the molecular method in the 121 nodules with indeterminate cytology was 90.1% (109/121), which was significantly higher than that of TIRADS classification, 74.4% (90/121) (P = 0.002).

Conclusion

The combined use of ultrasound, cytology, and BRAF^V600E mutation analysis is the most efficient and objective method for diagnosing PTMC. Both BRAF^V600E mutation and TIRADS classification are potentially useful adjuncts to differentiate thyroid nodules, especially indeterminate samples classified as BSRTC III.

Diffuse sclerosing variant of papillary thyroid carcinoma: outcomes of 33 cases

INTRODUCTION

Diffuse sclerosing variant of PTC (DSV-PTC) is an uncommon subtype of thyroid cancer. Although an aggressive behavior is often recognized, prognostic significance is still under debate.

OBJECTIVES

To describe the clinicopathological features and outcomes of a series of DSV-PTC patients.

METHODS

Retrospective data collection involving 33 patients diagnosed with DSV-PTC followed at the Endocrine Department of the Portuguese Institute of Oncology in Lisbon between 1981 and 2020.

RESULTS

Twenty-six patients (78.8%) were females with a mean age at presentation of 29.4 ± 11.7 years old. Mean time of follow-up was 19.5 ± 10.6 years (range 0.5-39). Histologically, bilateral tumors were present in 72.7% patients (n = 24), thyroid capsular invasion was documented in 57.6% (n = 19), 45.4% (n = 15) had extrathyroidal extension, and 42.4% (n = 14) had lymphovascular invasion. Most patients were staged pT3 (42.4%, n = 14) and pN1 (81.8%, n = 27). Median lymph nodes resected were 16. None of the patients showed distant metastases at presentation. All patients were treated at least once with 131I. During follow-up, four patients (14.8%), with persistent neck disease, were diagnosed with distant metastases, all of them in the lung. Two patients (1.8%) presented recurrent disease in the neck after being considered with no evidence of disease. At the last appointment, 18 patients (54.5%) were in remission, 4 (12.1%) had biochemical evidence of disease, 6 had structural disease, and for 5 patients disease status was considered as undetermined. There was no disease related mortality.

DISCUSSION/CONCLUSION

Our study confirms that DSV-PTC is diagnosed more often in young patients and exhibits a local extensive disease at presentation. On the other hand, even in the presence of distant metastases, no patient died during follow-up.

Identifying potential metabolic tissue biomarkers for papillary thyroid cancer in different iodine nutrient regions

PURPOSE

To investigate the applicability of metabolomics to select thyroid cancer-associated biomarkers and discover the effects of iodine on metabolic changes in thyroid cancer.

METHODS

In this study, a total of 33 papillary thyroid cancer (PTC) patients from areas with iodine excess and 32 PTC patients from areas with adequate iodine were recruited, and their cancerous tissue and paracancerous tissue were collected. These specimens were analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/QTOF/MS) in conjunction with multivariate statistical analysis.

RESULTS

Good separations were obtained for PTC tissue vs. paracancerous tissue, and 15 metabolites, including L-octanoylcarnitine, N-arachidonoylglycine, and others were found to be disturbed in PTC tissue. Moreover, the metabolic profile presented considerable separation between PTC tissue from different iodine areas, and 15 metabolomic biomarkers were found to be differentially expressed. Among them, 10 metabolites, including arachidonoylcarnitine and LysoPCs, were related to thyroid cancer and excess iodine. These biomarkers play a role in arachidonic acid metabolism pathways and others. In addition, biomarkers such as 3,5-tetradecadiencarnitine and oxidized glutathione were significantly correlated with thyroid function, and biomarkers such as L-octanoylcarnitine and arachidonic acid were significantly correlated with the clinical characteristics of PTC.

CONCLUSIONS

Distinct differences in metabolic profiles were found to exist between PTCs from areas with different levels of iodine nutrition. The identified biomarkers have significant potential for diagnosing PTC and investigating its underlying mechanisms.

Comparison of Korean vs. American Thyroid Imaging Reporting and Data System in Malignancy Risk Assessment of Indeterminate Thyroid Nodules

BACKGROUND

The management of cytologically indeterminate thyroid nodules is challenging for clinicians. This study aimed to compare the diagnostic performance of the Korean Thyroid Imaging Reporting and Data Systems (K-TIRADS) with that of the American College of Radiology (ACR)-TIRADS for predicting the malignancy risk of indeterminate thyroid nodules.

METHODS

Thyroid nodules diagnosed by fine-needle aspiration (FNA) followed by surgery or core needle biopsy at a single referral hospital were enrolled.

RESULTS

Among 200 thyroid nodules, 78 (39.0%) nodules were classified as indeterminate by FNA (Bethesda category III, IV, and V), and 114 (57.0%) nodules were finally diagnosed as malignancy by surgery or core needle biopsy. The area under the curve (AUC) was higher for FNA than for either TIRADS system in all nodules, while all three methods showed similar AUCs for indeterminate nodules. However, for Bethesda category III nodules, applying K-TIRADS 5 significantly increased the risk of malignancy compared to a cytological examination alone (50.0% vs. 26.5%, P=0.028), whereas applying ACR-TIRADS did not lead to a change.

CONCLUSION

K-TIRADS and ACR-TIRADS showed similar diagnostic performance in assessing indeterminate thyroid nodules, and K-TIRADS had beneficial effects for malignancy prediction in Bethesda category III nodules.

Nicotinic ganglionic acetylcholine receptor autoantibodies associated with paraneoplastic disease in a neuropsychiatric patient

Nicotinic ganglionic acetylcholine receptor autoantibodies (alpha-3-AChR Ab) are associated with paraneoplastic syndromes when present in low elevations. These antibodies can be tested for as part of an autoimmune encephalopathy panel in neuropsychiatric patients; a mildly elevated titre of alpha-3-AChR Ab that may start as an incidental finding can lead to the diagnosis of a previously undetected cancer. While alpha-3-AChR Ab are most typically associated with thymomas and small cell lung cancer, the presence of these antibodies can suggest a diverse range of other cancers. This case presents a patient with longstanding neuropsychiatric symptoms and possible functional hypothyroidism for whom a low elevation in alpha-3-AChR Ab led to the finding of papillary thyroid carcinoma.

Papillary thyroid carcinoma with hobnail features showing rapid progression and therapy resistance

BACKGROUND

Hobnail variant of papillary thyroid carcinoma (HVPTC), also designated as a micropapillary variant, is a rare but aggressive variant of PTC, representing <2% of all PTC. It was adopted in the newest World Health Organization classification. HVPTC is strongly associated with higher mortality in comparison to classic PTC and a high propensity for disease progression. This paper aimed to investigate the clinical course, cytological and histopathological features, and mutational profile of the hobnail variant from a unique case.

CASE REPORT

A case of a 38-year-old female patient with HVPTC is presented. Total thyroidectomy with central and bilateral, lateral lymphadenectomy was performed. The clinical course showed aggressive features, as lymph node metastasis and extrathyroidal extension were present at the presentation. Molecular and immunohistochemical features are addressed along with a review of the literature.

DISCUSSION

The cytological examination of FNA was in consonance with published literature. The cells showed hobnail features in several segments of both thyroidal lobes on histological examination. The tumour displayed a typical BRAF mutation and Gly12Ala mutation in the KRAS gene, previously not associated with PTC.

CONCLUSION

We aimed to highlight the aggressive, clinicopathological features of this high-risk variant. We emphasise the need to evaluate suspicious thyroid nodules as an adequate diagnosis can prevent delayed therapy. It directly impacts the tumour's stage and prognosis. In fine-needle aspiration cytology showing papillary architecture carcinomas, HVPTC has to be part of the differential diagnosis.

Hobnail variant of papillary thyroid carcinoma: a systematic review and meta-analysis

OBJECTIVE

The hobnail variant of papillary thyroid carcinoma (HVPTC) has emerged as a rare and aggressive variant of papillary thyroid carcinoma (PTC). We aim to determine the prevalence and clinicopathologic factors of HVPTC.

METHODS

A systematic review of the literature for studies examining HVPTC was performed. Four databases (PubMed, Scopus, OVID, Cochrane library) were queried from inception of databases through March 20th, 2020.

RESULTS

Sixteen studies with 124 cases of HVPTC were included. The mean age for all patients was 52.3 years. HVPTC had a prevalence of 1.08% out of all PTC cases, with a mean tumor size of 3.1 cm. In 62% and 50% of cases, lymphovascular invasion and extrathyroidal extension were present, respectively. Follow-up data, with a mean of 49.9 months, revealed a 66% rate of lymph node metastasis and 23% rate of distant metastasis. Tumors with ≥30% hobnail morphology had a 2.6-fold increased odds of developing lymph node metastasis compared with <30% hobnail morphology, however did not differ in rates of distant metastasis. Patients ≥55 years old had a 4.5-fold increased odds of distant metastasis and a 4.7-fold increased odds of lymphovascular invasion over patients <55.

CONCLUSIONS

High rates of locoregional and distant disease as well as high-risk pathological factors reveal the aggressive nature of HVPTC. Diagnostic criteria regarding percentage of hobnail morphology requires further refinement. Further studies are warranted in order to better understand how recognition of this high-risk variant impacts clinical treatment.

Identification of key genes of papillary thyroid carcinoma by integrated bioinformatics analysis

BACKGROUND

Papillary thyroid carcinoma (PTC) is one of the fastest-growing malignant tumor types of thyroid cancer. Therefore, identifying the interaction of genes in PTC is crucial for elucidating its pathogenesis and finding more specific molecular biomarkers.

METHODS

Four pairs of PTC tissues and adjacent tissues were sequenced using RNA-Seq, and 3745 differentially expressed genes were screened (P<0.05, |logFC|>1). The enrichment analysis indicated that the vast majority of differentially expressed genes (DEGs) may play a positive role in the development of cancer. Then, the significant modules were analyzed using Cytoscape software in the protein-protein interaction network. Survival analysis, TNM analysis, and immune infiltration analysis of key genes were analyzed. And the expression of ADORA1, APOE, and LPAR5 genes were verified by qPCR in PTC compared with matching adjacent tissues.

RESULTS

Twenty-five genes were identified as hub genes with nodes greater than 10. The expression of 25 genes were verified by the GEPIA database, and the overall survival and disease-free survival analyses were conducted with Kaplan-Meier plotter. We found only three genes were confirmed with our validation and were statistically significant in PTC, namely ADORA1, APOE, and LPAR5. Further analysis found that the mRNA levels and methylation degree of these three genes were significantly correlated with the TNM staging of PTC. And these three genes were related to PTC immune infiltration. Verification of the expression of these three genes by RT-qPCR and Western blot further confirmed the reliability of our results.

CONCLUSION

Our study identified three genes that may play key regulatory roles in the development, metastasis, and immune infiltration of papillary thyroid carcinoma.

Comprehensive evaluation of risk factors for lymph node metastasis in patients with papillary thyroid carcinoma

With the increasing incidence of papillary thyroid cancer (PTC), it is important to risk-stratify patients who may have a more aggressive tumor biology. The present study aimed to evaluate the risk factors for lymph node metastasis (LNM) in patients with PTC, which may provide a significant reference for clinical diagnosis and treatment. In total, 1,045 patients with PTC [313 with PT microcarcinoma (PTMC) and 732 with non-PTMC] between August 2016 and August 2019 were investigated. The B-type Raf kinase (BRAF) V600E mutation was tested in all samples. The clinical data (sex, age, tumor location, sample type and pathological features) were retrospectively analyzed. Logistic regression analysis was performed to evaluate independent risk factors for LNM. A total of 181/313 (57.8%) PTMC cases and 145/732 (19.8%) non-PTMC cases had a BRAF V600E mutation. In the PTMC cases, significant differences in sex and sample type were identified (BRAF V600E mutation vs. wild-type). In the non-PTMC cases, significant differences in sex and age were identified (BRAF V600E mutation vs. wild-type). Female sex and tumor diameter ≤1 cm were significant independent predictors of LNM in PTC. In PTMC, female sex was a significant independent predictor of LNM. A bilateral tumor was an independent protective factor for LNM in PTC, PTMC and non-PTMC. The BRAF V600E mutation rate of ultrasound-guided fine-needle aspiration cytology was higher compared with FFPE in PTMC (P=0.018). In contrast to previous studies, the results of the present study suggested that being female and having a tumor of diameter ≤1 cm were risk factors for LNM, and that the BRAF wild-type of PTMC may be more aggressive than other types. Notably, the position of the tumor in the bilateral thyroid was also an independent protective factor for LNM. Therefore, ultrasound-guided fine-needle aspiration should be recommended for gene analysis (BRAF V600E) in PTMC. In addition, clinicians should consider an individualized treatment according to gene mutations, sex, age, tumor size and the location of the tumor, in order to achieve an improved therapeutic efficacy.

Thyroid Carcinoma: Phenotypic Features, Underlying Biology and Potential Relevance for Targeting Therapy

Thyroid carcinoma consists a group of phenotypically heterogeneous cancers. Recent advances in biological technologies have been advancing the delineation of genetic, epigenetic, and non-genetic factors that contribute to the heterogeneities of these cancers. In this review article, we discuss new findings that are greatly improving the understanding of thyroid cancer biology and facilitating the identification of novel targets for therapeutic intervention. We review the phenotypic features of different subtypes of thyroid cancers and their underlying biology. We discuss recent discoveries in thyroid cancer heterogeneities and the critical mechanisms contributing to the heterogeneity with emphases on genetic and epigenetic factors, cancer stemness traits, and tumor microenvironments. We also discuss the potential relevance of the intratumor heterogeneity in understanding therapeutic resistance and how new findings in tumor biology can facilitate designing novel targeting therapies for thyroid cancer.

CircRNA_104565 Promoted Cell Proliferation in Papillary Thyroid Carcinoma by Sponging miR-134

BACKGROUND

Thyroid cancer is one of the most common cancers with rising incidence worldwide, and papillary thyroid carcinoma (PTC) accounts for 80-85% of thyroid malignancy. Although it has been reported that many genes relate to the carcinogenesis of PTC, the molecular mechanisms remain mostly unclear.

METHODS

QRT-PCR assay was performed to detect circRNA_104565, miR-134 and ELF2 expression. CCK8 assay was exercised to examine cell proliferation. Western blot was used to detect ELF2 expression.

RESULTS

We found that circRNA_104565 was highly expressed in PTC tissue and cell and promoted cell proliferation in vitro and in vivo. In addition, circRNA_104565 promoted cell proliferation in PTC by regulating the miR-134/ELF2 axis.

CONCLUSION

Hence, revealing the function of circRNA_104565 in PTC is important for understanding the molecular mechanism of carcinogenesis and providing new biomarkers or therapeutic targets for PTC.

Cytomorphologic features as predictors of aggressiveness in patients with pT1 papillary thyroid carcinoma: a retrospective study of associations with clinicopathological parameters in 226 fine-needle aspirates

Background

Distinguishing aggressive pT1 papillary thyroid carcinomas (PTCs) from indolent PTCs before or during surgery is important. To the best of our knowledge, few reports in the literature have examined the value of the cytomorphologic features of PTC as predictors of aggressiveness.

Methods

This retrospective study included 226 pT1 PTC patients who underwent preoperative fine-needle aspiration cytology (FNAC) and surgery at Peking University Cancer Hospital between January 2018 and December 2019. Data on the clinical characteristics and pathological results were obtained from the electronic medical record database. All FNAC smears were blindly reviewed by two independent cytopathologists, and the associations between nine cytomorphologic features (lymphocytes, multinucleated giant cells, cellularity, cellular adhesiveness, nuclear size, nuclear pleomorphism, nuclear membrane regularity, intranuclear pseudoinclusions and the amount of cytoplasm) and clinicopathological parameters were statistically analyzed.

Results

Univariate analysis showed that cellularity, intranuclear pseudoinclusions, cellular adhesiveness, nuclear size, and nuclear pleomorphism were strong predictors of some clinicopathological parameters such as extracapsular invasion (ECI) and lymph node metastasis (LNM). Multivariate analysis confirmed that cellular adhesiveness was a strong independent predictor of ECI (P=0.001) and LNM (P<0.001), and the amount of cytoplasm can also predict LNM (P=0.024).

Conclusions

Cytomorphologic features including cellular adhesiveness and the amount of cytoplasm in preoperative FNAC smears could be a valuable tool for predicting ECI or LNM and may be predictors of aggressiveness in patients with pT1 PTC.

A MATHEMATICAL MODEL FOR TREATMENT OF PAPILLARY THYROID CANCER USING THE ALLEE EFFECT

The incidence of thyroid cancer is rising all over the world, and the papillary subtype (PTC) is the primary factor for this increase. The presence of thyroid tumors is commonly associated with increased levels of cytokines, such as interleukin 6 (IL-6). Considering PTC patients treated with thyroidectomy and radioactive iodine [Formula: see text]I (RAI), we propose an ordinary differential system using four variables: the RAI activity, the number of cancer cells and the serum concentrations of IL-6 and thyroglobulin (Tg). Our objective is to study the efficacy of different therapeutic doses of RAI in the treatment of thyroid cancer. The Allee effect is taken into account when modeling cancer cells growth under the influence of IL-6. From the results obtained, the main factors and conditions correlated with successful treatment, such as the RAI activity used and the tumor response are addressed. The detection of minimal doses of RAI that can cause tumor extinction is performed, though this has also meant longer periods for tumor cell elimination. The critical number of tumor cells due to the Allee effect is analyzed and linked to the immune system or biological factors that can slow the progression of the tumor but are insufficient after thyroid resection surgery.

Overexpression of novel long intergenic non‑coding RNA LINC02454 is associated with a poor prognosis in papillary thyroid cancer

It has been revealed from microarray data analysis that long intergenic non-coding RNA 02454 (LINC02454) is highly expressed in papillary thyroid cancer (PTC). The aim of the present study was to explore the potential role of LINC02454 in the tumorigenesis of PTC. The mRNA expression levels of LINC02454 were assessed using data from The Cancer Genome Atlas (TCGA) and the GSE66783 cohort in thyroid cancer, and were validated using reverse transcription-quantitative PCR in 104 patients with PTC recruited in the present study. The association between the LINC02454 mRNA expression levels and the clinicopathological features of the 104 patients with PTC were also analyzed. Functional enrichment analyses were conducted on the differentially expressed genes in the high and low LINC02454 expression groups that were identified from the TCGA cohort. RNA interference, using short interfering (si)RNA against LINC02454, was used to investigate the role of LINC02454 in the biological functions of PTC cells in vitro. The expression level of LINC02454 was significantly increased in PTC tissues (P=0.0011) and was significantly associated with a larger tumor size, T stage, an advanced TNM stage and an increased lymph node metastasis (P<0.05), which was consistent with that in the TCGA and GSE66783 cohort. High expression levels of LINC02454 were observed in patients with PTC that also had BRAF mutations (P<0.001), and were significantly associated with a poorer disease-free survival in the TCGA cohort (P<0.05). Functional enrichment analysis indicated that LINC02454-related genes were significantly enriched in Gene Ontology terms, such as ‘positive regulation of cell proliferation’, ‘positive regulation of cell division’ and ‘cell adhesion’, and the following Kyoto Encyclopedia of Genes and Genomes pathways: ‘Pathways in cancer’ ‘proteoglycans in cancer’ and ‘ECM-receptor interaction’. In vitro, the knockdown of LINC02454 markedly arrested the cells in the G₀/G₁ phase of the cell cycle, and also led to an overall increase in apoptosis, as well as to an unexpected decrease in cell proliferation. LINC02454 may thus potentially function as an oncogene, which inhibits the apoptosis and enhances proliferation of PTC cells. Thus, as suggested by the findings of the present study, LINC02454 may be used as a diagnostic and prognostic biomarker for PTC in the future.

The Fractal and GLCM Textural Parameters of Chromatin May Be Potential Biomarkers of Papillary Thyroid Carcinoma in Hashimoto's Thyroiditis Specimens

Occasionally, Hashimoto's thyroiditis (HT) and papillary thyroid carcinoma (PTC) share similar nuclear features. The current study aims to quantify the differences between the investigated specimens of HT-associated PTC versus the HT alone, to reduce the subjective experience of an observer, by the use of fractal parameters as well as gray-level co-occurrence matrix (GLCM) textural parameters. We have analyzed 250 segmented nuclei per group (nn = 25 per patient and np = 10 patients per group) using the ImageJ software (NIH, Bethesda, MD, USA) as well as an in-house written code for the GLCM analysis. The mean values of parameters were calculated for each patient. The results demonstrated that the malignant cells from the HT-associated PTC specimens showed lower chromatin fractal dimension (p = 0.0321) and higher lacunarity (p = 0.0038) compared with the corresponding cells from the HT specimens. Also, there was a statistically significant difference between the investigated specimens, in the contrast, correlation, angular second moment, and homogeneity, of the GLCM corresponding to the visual texture of follicular cell chromatin. The differences in chromatin fractal and GLCM parameters could be integrated with other diagnostic methods for the improved evaluation of distinctive features of the HT-associated PTC versus the HT in cytology and surgical pathology specimens.

Noninvasive follicular neoplasm with papillary like nuclear features: A comprehensive analysis with a diagnostic algorithm

BACKGROUND

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) lacks the carcinoma label, avoiding aggressive therapy, physiological, social and financial impact of cancer diagnosis. Unfortunately, the preoperative diagnosis is still a challenge. Varied incidence of NIFTP has been document with limited data on preoperative cytological, radiological characteristics and the impact on risk of malignancy in each category of the Bethesda system of reporting thyroid cytopathology.

METHOD

Retrospective analysis of 20 NIFTPs with an attempt to provide a preoperative diagnostic algorithm based on the cytological and ultrasound features along with incidence and implication on risk of malignancy in various Bethesda categories with its impact on patient management.

RESULT

Incidence of NIFTP in our study was higher in comparison to that documented from other Asian countries. TIRADS 3 was the most common sonographic diagnosis. NIFTP was commonly preceded by indeterminate or benign Bethesda category. Major impact of excluding NIFTP form malignant category was seen on Bethesda categories II and IV with 20% and 27% reduction in risk of malignancy, respectively.

CONCLUSION

Retrospective analysis should not be confined only to follicular variant of papillary thyroid carcinoma but cases of follicular adenoma and adenomatous colloid nodule should always be included in review to ascertain the true incidence of NIFTP. NIFTPs are less likely to have malignant preoperative cytology. NIFTP shares major cytological and ultrasound features with follicular adenoma, adenomatous colloid nodule and minimally invasive follicular papillary carcinoma. When analyzed together, taking minor findings in consideration, can favor a diagnosis.

Variants of Papillary Thyroid Carcinoma: An Algorithmic Cytomorphology-Based Approach to Cytology Specimens

BACKGROUND

Thyroid cancer accounts for 1% of cancer cases in developed countries, in which papillary thyroid carcinoma (PTC) is the most common type. There are multiple variants of PTC described to date, some of them with aggressive behavior and poor clinical outcome. These variants are well described and accepted in recent guidelines of many international societies, and the prognostic and management implications are well laid out. Due to their established clinical importance and to guide appropriate surgical management, it is now imperative in clinical practice, including cytopathology, to differentiate aggressive variants from nonaggressive ones. This review aims to describe the variants of PTC and to provide a practical algorithmic approach to facilitate the cytological diagnosis of these variants.

SUMMARY

Subtyping PTC variants on fine needle aspiration cytology (FNAC) is challenging even for the most experienced cytopathologist. To facilitate a correct subtyping on FNAC, we propose a stepwise approach that is mainly designed for conventional smear methodology. This approach requires first to stratify the lesions into oncocytic and nononcocytic features before analyzing further details in cell morphology and pattern. Key Messages: (1) Subtyping in PTC is possible on cytopathology. (2) The main aim of the cytopathologist is to differentiate aggressive from nonaggressive variants. (3) The subtyping of PTC can help in the surgical management of the patients.

The impact of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) on the diagnosis of thyroid nodules

More than 70 years ago, Prof. Pierre Masson, a renowned French-Canadian pathologist (1880-1959), advised us that "No classification is more difficult to establish than that of thyroid carcinomas…Of all cancers, they teach, perhaps, the greatest lessons of humility to histopathologists." Almost 70 years later, the recent evidence-based reclassification of the non-invasive encapsulated follicular variant of papillary thyroid carcinoma (FVPTC) as non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), has demonstrated that this problematic is still ongoing. For about 30 years, it was wrongly assumed that the encapsulated FVPTC behaved and spread like its classical counterpart and, therefore, that it should be treated likewise. As such, the renaming of a malignant entity as a nonmalignant (albeit not benign) neoplasm has contributed to optimizing patient care by deescalating treatment and follow-up for an indolent neoplasm, decreasing medical expense and complications possibly caused by further treatment including radioactive iodine, and reassuring patients with this diagnosis. At the same time, NIFTP has significant implications not only for the practice of thyroid cytopathology but also for surgical pathology and for molecular tests, creating significant new challenges. NIFTP has rigorous histopathologic diagnostic criteria, including papillary-like nuclear features, and submission of the entire tumor capsule and content is required to exclude both invasion and presence of papillary structures. Cytologically, because of the morphological overlap with other follicular neoplasms and with papillary thyroid carcinoma (PTC), most NIFTP are diagnosed into one of the indeterminate Bethesda categories (III-V) and can be adequately triaged for surgery. From a molecular view, NIFTP are most often characterized by RAS-type mutations, similar to other follicular-patterned lesions, and molecular testing can be helpful to suggest NIFTP preoperatively. In this review, we focus on the impact of NIFTP on the diagnosis of thyroid nodules.

Cytologic features of aggressive variants of follicular-derived thyroid carcinoma

Certain carcinomas of the thyroid gland behave aggressively resulting in increased patient morbidity and poor patient prognosis. The diagnosis of these aggressive thyroid cancer subtypes is sometimes challenging and subject to increased interobserver variability. This review deals with the cytological features of such tumors including aggressive variants of papillary thyroid carcinoma, poorly differentiated thyroid carcinoma, and anaplastic thyroid carcinoma. These malignancies fall into 2 groups based on their cytomorphology: those that exhibit distinct microscopic features (eg, nuclear findings typical of classical papillary thyroid carcinoma or marked anaplasia) and those that present with more subtle cytologic features (eg, nuclear pseudostratification, "soap bubble" nuclei, supranuclear or subnuclear cytoplasmic vacuoles, rosette-like structures, hobnail cells). We review the literature regarding these aggressive thyroid cancers and highlight important phenotypic characteristics that can be useful for their diagnosis based on fine needle aspiration.

Prediction of novel target genes and pathways involved in tall cell variant papillary thyroid carcinoma

BACKGROUND

Tall cell variant papillary thyroid carcinoma (TCPTC) is reportedly associated with aggressive clinicopathological parameters and poor outcomes; however, the molecular mechanisms underlying TCPTC remain poorly understood.

METHODS

The gene mutation types and mRNA expression profiles of patients with TCPTC were obtained from The Cancer Genome Atlas (TCGA) database. Differentially expressed genes (DEGs) were identified. Pathways in the interaction network and the diagnostic approaches of candidate markers for TCPTC were investigated.

RESULTS

BRAF mutation was particularly prevalent in TCPTC with a mutation frequency of 78%. TCPTC was associated with a patient age >45 years, tumor multifocality, extrathyroidal extension, a higher T stage, advanced AJCC TNM stages, BRAF V600E mutation, and poor disease-free survival. We identified 4138 TCPTC-related DEGs and 301 TCPTC-specific DEGs. Intriguingly, the gene expression pattern revealed that the dysregulated levels of both putative oncogenes and tumor suppressors in TCPTC were higher than those in classical/conventional variant PTC (cPTC). Functional enrichment analyses revealed that these DEGs were involved in several cancer-related pathways. A protein-protein interaction (PPI) network was constructed from the 301 TCPTC-specific DEGs, and 3 subnetworks, and 8 hub genes were verified. Receiver operating characteristic (ROC) analyses revealed that 6 hub genes, including COL5A1, COL1A1, COL10A1, COL11A1, CCL20, and CXCL5, could be used not only for the differential diagnosis of PTC from normal samples, but also for the differential diagnosis of TCPTC from cPTC samples.

CONCLUSIONS

Our study might provide further insights into the investigations of the tumorigenesis mechanism of TCPTC and assists in the discovery of novel candidate diagnostic markers for TCPTC.

Patients with Oncocytic Variant Papillary Thyroid Carcinoma Have a Similar Prognosis to Matched Classical Papillary Thyroid Carcinoma Controls

BACKGROUND

Previous studies have suggested that oncocytic variant papillary thyroid carcinoma (PTC) may be more aggressive, with higher rates of recurrent disease. The aim of this study was to evaluate characteristics and outcomes of patients with oncocytic variant PTC compared to classical PTC.

METHODS

Patients with oncocytic variant PTC were retrospectively identified from 519 patients who underwent thyroidectomy for PTC between January 2009 and August 2015. Data collected included patient demographics, laboratory and pathology findings, imaging studies, treatment, and follow-up. Patients were matched 1:1 by age, sex, and TNM stage with patients who underwent total thyroidectomy for classical PTC during the same time period.

RESULTS

The cohort included 21 patients, of whom 18 (86%) were female, with a median age of 53 years (range 23-68 years). All patients underwent total thyroidectomy, and 17 (81%) had a central compartment neck dissection (8 [38%] prophylactic). The median tumor size was 2.0 cm (range 0.9-6.5 cm), and four (19%) patients had extrathyroidal extension. There was no significant difference in histopathologic characteristics, including extrathyroidal extension and lymphovascular invasion, between the two groups except for an increased incidence of thyroiditis in oncocytic variant PTC (90.5% vs. 57%; p = 0.01). In oncocytic variant PTC patients who underwent central compartment neck dissection, malignant lymph nodes were found in 12 (57%) patients compared to 13 (62%) classical (p = 0.75). Lateral neck dissection was performed in 5 (24%) oncocytic variant and classical PTC patients, with metastatic lymphadenopathy found in four (a median of four malignant lymph nodes; range 1-6) and five (a median of 2.5 malignant lymph nodes; range 1-9), respectively. Radioactive iodine was administered to 18 (86%) oncocytic variant PTC and 18 (86%) classical PTC patients. At a median follow-up of 51 months (interquartile range 38-61), one oncocytic variant PTC patient had recurrent disease and underwent reoperation at 24 months. In classical PTC patients with a median follow-up time of 77 months (range 56-87 months), two (9.5%) patients had detectable thyroglobulin levels indicating early recurrence, but neither has undergone reoperation.

CONCLUSIONS

Oncocytic variant PTC was present in 5% of PTC patients. Most (95%) patients remain disease-free at four years, similar to classical PTC outcomes, suggesting that oncocytic variant may not represent a more aggressive variant.