Oncogenic alterations in papillary thyroid cancers of young patients

Application value of multi-gene mutation detection in the clinical management of pediatric papillary thyroid carcinoma: a preliminary exploration

Objectives

Thyroid cancer rarely occurs in children and adolescents. Molecular markers such as BRAF, RAS, and RET/PTC have been widely used in adult PTC. It is currently unclear whether these molecular markers have equivalent potential for application in pediatric patients. This study aims to explore the potential utility of a multi-gene conjoint analysis based on next-generation targeted sequencing for pediatric papillary thyroid carcinoma (PTC).

Materials and methods

The patients diagnosed with PTC (aged 18 years or younger) in the pediatrics department of Lishui District Hospital of Traditional Chinese Medicine were retrospectively screened. A targeted enrichment and sequencing analysis of 116 genes associated with thyroid cancer was performed on paraffin-embedded tumor tissues and paired paracancerous tissue of fifteen children (average age 14.60) and nine adults (average age 49.33) PTC patients. Demographic information, clinical indicators, ultrasonic imaging information and pathological data were collected. The Kendall correlation test was used to establish a correlation between molecular variations and clinical characteristics in pediatric patients.

Results

A sample of 15 pediatric PTCs revealed a detection rate of 73.33% (11/15) for driver gene mutations BRAF V600E and RET fusion. Compared to adult PTCs, the genetic mutation landscape of pediatric PTCs was more complex. Six mutant genes overlap between the two groups, and an additional seventeen unique mutant genes were identified only in pediatric PTCs. There was only one unique mutant gene in adult PTCs. The tumor diameter of pediatric PTCs tended to be less than 4cm (p<0.001), and the number of lymph node metastases was more than five (p<0.001). Mutations in specific genes unique to pediatric PTCs may contribute to the onset and progression of the disease by adversely affecting hormone synthesis, secretion, and action mechanisms, as well as the functioning of thyroid hormone signaling pathways. But, additional experiments are required to validate this hypothesis.

Conclusion

BRAF V600E mutation and RET fusion are involved in the occurrence and development of adolescent PTC. For pediatric thyroid nodules that cannot be determined as benign or malignant by fine needle aspiration biopsy, multiple gene combination testing can provide a reference for personalized diagnosis and treatment by clinical physicians.

Genetic alterations landscape in paediatric thyroid tumours and/or differentiated thyroid cancer: Systematic review

Differentiated thyroid cancer (DTC) is a rare disease in the paediatric population (≤ 18 years old. at diagnosis). Increasing incidence is reflected by increases in incidence for papillary thyroid carcinoma (PTC) subtypes. Compared to those of adults, despite aggressive presentation, paediatric DTC has an excellent prognosis. As for adult DTC, European and American guidelines recommend individualised management, based on the differences in clinical presentation and genetic findings. Therefore, we conducted a systematic review to identify the epidemiological landscape of all genetic alterations so far investigated in paediatric populations at diagnosis affected by thyroid tumours and/or DTC that have improved and/or informed preventive and/or curative diagnostic and prognostic clinical conduct globally. Fusions involving the gene RET followed by NTRK, ALK and BRAF, were the most prevalent rearrangements found in paediatric PTC. BRAF V600E was found at lower prevalence in paediatric (especially ≤ 10 years old) than in adults PTC. We identified TERT and RAS mutations at very low prevalence in most countries. DICER1 SNVs, while found at higher prevalence in few countries, they were found in both benign and DTC. Although the precise role of DICER1 is not fully understood, it has been hypothesised that additional genetic alterations, similar to that observed for RAS gene, might be required for the malignant transformation of these nodules. Regarding aggressiveness, fusion oncogenes may have a higher growth impact compared with BRAF V600E. We reported the shortcomings of the systematized research and outlined three key recommendations for global authors to improve and inform precision health approaches, glocally.

Ultrasound-Based Nomogram for Predicting the Aggressiveness of Papillary Thyroid Carcinoma in Adolescents and Young Adults

RATIONALE AND OBJECTIVES

Assessing the aggressiveness of papillary thyroid carcinoma (PTC) preoperatively might play an important role in guiding therapeutic strategy. This study aimed to develop and validate a nomogram that integrated ultrasound (US) features with clinical characteristics to preoperatively predict aggressiveness in adolescents and young adults with PTC.

MATERIALS AND METHODS

In this retrospective study, a total of 2373 patients were enrolled and randomly divided into two groups with 1000 bootstrap sampling. The multivariable logistic regression (LR) analysis or least absolute shrinkage and selection operator LASSO regression was applied to select predictive US and clinical characteristics in the training cohort. By incorporating most powerful predictors, two predictive models presented as nomograms were developed, and their performance was assessed with respect to discrimination, calibration, and clinical usefulness.

RESULTS

The LR_model that incorporated gender, tumor size, multifocality, US-reported cervical lymph nodes (CLN) status, and calcification demonstrated good discrimination and calibration with an area under curve (AUC), sensitivity and specificity of 0.802 (0.781-0.821), 65.58% (62.61%-68.55%), and 82.31% (79.33%-85.46%), respectively, in the training cohort; and 0.768 (0.736-0.797), 60.04% (55.62%-64.46%), and 83.62% (78.84%-87.71%), respectively, in the validation cohort. Gender, tumor size, orientation, calcification, and US-reported CLN status were combined to build LASSO_model. Compared with LR_model, the LASSO_model yielded a comparable diagnostic performance in both cohorts, the AUC, sensitivity, and specificity were 0.800 (0.780-0.820), 65.29% (62.26%-68.21%), and 81.93% (78.77%-84.91%), respectively, in the training cohort; and 0.763 (0.731-0.792), 59.43% (55.12%-63.93%), and 84.98% (80.89%-89.08%), respectively, in the validation cohort. The decision curve analysis indicated that using the two nomograms to predict the aggressiveness of PTC provided a greater benefit than either the treat-all or treat-none strategy.

CONCLUSION

Through these two easy-to-use nomograms, the possibility of the aggressiveness of PTC in adolescents and young adults can be objectively quantified preoperatively. The two nomograms may serve as a useful clinical tool to provide valuable information for clinical decision-making.

More aggressive biological behavior in pediatric than in adult papillary thyroid carcinoma

OBJECTIVE

Papillary thyroid carcinoma (PTC) remains a common malignancy of the endocrine system in children and adolescents. This study aimed to investigate the differences in clinical characteristics between children and adults with PTC.

METHODS

A total of 360 patients [ 308 adults (≥20 years) and 52 children and adolescents (<20 years)] with PTC who underwent thyroid surgery in our center from 2017 to 2022 were retrospectively analyzed. Statistical analysis and comparisons of the clinicopathological data and tumor characteristics between children and adults were performed.

RESULTS

Among all enrolled patients, the mean tumor diameter was 26.21 ± 12.72 mm in the pediatric group, while that in the adult group was 11.62 ± 10.21 mm, which was a significant difference (p < 0.001). Pediatric patients were more prone to central lymph node metastasis (90.38% vs. 49.35%, p<0.001), lateral lymph node metastasis (78.85% vs. 45.7%, p<0.001), capsular invasion (90.38% vs. 63.96%, p<0.001) and extrathyroidal extension (61.54% vs. 15.26%, p＜0.001) than adult patients. However, the pediatric group had a lower BRAFV600E mutation rate (54.76% vs. 87.7%, p < 0.001) and lower incidence of Hashimoto's thyroiditis (15.38% vs. 30.84%, p = 0.023) than the adult group. There were no significant differences in clinicopathological factors, such as sex, multifocality and hypothyroidism.

CONCLUSIONS

Pediatric patients were more likely to present with advanced disease at diagnosis, including larger tumor volume, more lymph node metastasis, more extensive local invasion, and lower rates of BRAF mutation and concomitant Hashimoto's thyroiditis. Therefore, appropriate surgical management and comprehensive treatment decisions are needed for pediatric patients with PTC.

BRAFV600E Positivity-Dependent Effect of Age on Papillary Thyroid Cancer Recurrence Risk

BRAFV600E positivity is associated with increased aggressiveness of papillary thyroid cancer (PTC), and age is an important prognostic factor. However, the association between age and BRAFV600E positivity and the recurrence risk has not been investigated. This study aimed to investigate the impact of age on recurrence between patients with BRAFV600E-positive and -negative PTC. Patients with PTC who underwent initial thyroid surgery between January 2010 and December 2018 at Seoul St. Mary's Hospital (Seoul, Republic of Korea) were retrospectively reviewed. The BRAFV600E-positive (n = 1768) and BRAFV600E-negative groups (n = 428) were divided into two subgroups: younger (<35 years) and older groups (≥55 years). In the BRAFV600E-positive group, the younger group exhibited higher lymphatic and vascular invasion rates, more positive lymph nodes, higher lymph node ratios, and higher recurrence rates than the older group (5.9% vs. 2.1%). Multivariate analysis revealed that age, lymphatic invasion, and N category were significant risk factors in the BRAFV600E-positive group. In the BRAFV600E-positive group, the younger group had a higher recurrence risk than the older group (OR, 2.528; 95% confidence interval, 1.443-4.430; p = 0.001). In the BRAFV600E-negative group, age had no impact on recurrence risk. These results contribute to tailored treatment strategies and informed patient management.

Single BRAFV600E mutation is not associated with aggressive biological behavior in adolescent and pediatric papillary thyroid carcinoma

BACKGROUND

Papillary thyroid carcinoma is more likely to show aggressive biological behaviors in the majority of pediatric patients than in adult patients. The aim of this study was to investigate the mutation rate of the BRAFV600E gene in adolescents and children with papillary thyroid carcinoma and to analyze the association between BRAFV600E gene mutation and tumor-aggressive pathological factors.

METHODS

A total of 42 pediatric patients with papillary thyroid carcinoma who underwent thyroid surgery from 2017 to 2022 were studied retrospectively. Whether the BRAFV600E gene mutation in papillary thyroid carcinoma was related to aggressive biological behavior was analyzed.

RESULTS

Among the 42 pediatric patients with papillary thyroid carcinoma, the median patient age was 15.71 ± 2.51 years (mean ± SD) and the median tumor diameter was 24.95 ± 12.29 mm (mean ± SD). Among all enrolled patients, the mutation rate of the BRAFV600E gene was 54.76% (23 of 42). There were 33 patients with classic papillary thyroid carcinoma, and 22 (66.67%) with classic subtypes were BRAFV600E positive. The BRAFV600E mutation was associated with lower distant metastasis (p = .013) and less Hashimoto's thyroiditis (p = .006). There was no significant difference in clinicopathological factors such as sex, age, tumor size, capsular invasion, multifocality, hypothyroidism, recurrence, lymph node metastasis, and extrathyroidal extension.

CONCLUSIONS

The BRAFV600E mutation is not uncommon in pediatric papillary thyroid carcinoma but is not significantly associated with aggressive biological behavior. It is not possible to determine whether to adopt more active diagnosis and treatment measures on the basis of the mutation of a single BRAFV600E gene.

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.

Paediatric differentiated thyroid carcinoma: a UK National Clinical Practice Consensus Guideline

This guideline is written as a reference document for clinicians presented with the challenge of managing paediatric patients with differentiated thyroid carcinoma up to the age of 19 years. Care of paediatric patients with differentiated thyroid carcinoma differs in key aspects from that of adults, and there have been several recent developments in the care pathways for this condition; this guideline has sought to identify and attend to these areas. It addresses the presentation, clinical assessment, diagnosis, management (both surgical and medical), genetic counselling, follow-up and prognosis of affected patients. The guideline development group formed of a multi-disciplinary panel of sub-speciality experts carried out a systematic primary literature review and Delphi Consensus exercise. The guideline was developed in accordance with The Appraisal of Guidelines Research and Evaluation Instrument II criteria, with input from stakeholders including charities and patient groups. Based on scientific evidence and expert opinion, 58 recommendations have been collected to produce a clear, pragmatic set of management guidelines. It is intended as an evidence base for future optimal management and to improve the quality of clinical care of paediatric patients with differentiated thyroid carcinoma.

The clinical significance of BRAFV600E mutations in pediatric papillary thyroid carcinomas

This study aimed to review the clinical significance of BRAFV600E mutations in pediatric papillary thyroid carcinoma (PTC). From 2018 to 2021, 392 pediatric thyroid operations were performed in the first affiliated Hospital of Zhengzhou University. Of these, 169 patients underwent their first operation in our hospital and were histopathologically diagnosed as papillary thyroid carcinoma. BRAFV600E gene mutation detection was performed in these 169 pediatric patients to investigate the correlation between BRAF gene mutations and clinicopathological features. Ninety-seven of our 169 patients had a BRAFV600E mutation, with a mutation rate of 57.4%. The incidence of BRAFV600E was higher in boys than in girls, and in the 13-18-year age group as compared with the 6-12-year age group (P < 0.05). The positivity rate of BRAFV600E in unilateral PTC (67.7%) was significantly higher than the ones in bilateral PTC (28.9%). The occurrence of diffuse microcalcification of the thyroid negatively correlated with the presence of BRAFV600E mutations. BRAFV600E mutations were found more frequently in patients with smaller tumor size, a lack of multifocality, lower TSH levels and central lymph node metastasis. During the follow-up time, 70 patients were treated with iodine-131. Eight patients required a second surgery (All had cervical lymph node recurrence). BRAFV600E mutations do not suggest a more aggressive course in papillary thyroid carcinoma in pediatric patients in the short term.

Mutational analysis using next generation sequencing in pediatric thyroid cancer reveals BRAF and fusion oncogenes are common

BACKGROUND

We previously described mutation rates of BRAF^V600E, RAS, RET-PTC and PAX8-PPARγ in pediatric subjects with well-differentiated thyroid cancer (WDTC). We expanded the cohort adding next-generation sequencing (NGS) and assessed genotype-phenotype correlations.

METHODS

Single-center retrospective cohort examining thyroidectomy tissue blocks from consecutive pediatric WDTC patients between 2001 and 2015. Tissues were analyzed at Quest Diagnostics for BRAF, RAS mutations, RET-PTC and PAX8-PPARγ, and additional fusions, using standalone and NGS tests. WDTC included papillary (PTC), follicular (FTC) and follicular-variant PTC (FVPTC).

RESULTS

We genotyped 46 samples (36 females). Mean age at diagnosis was 14.7 years and the cohort comprised of mostly Hispanic (60.9%) and Caucasian (26.1%) patients. Mean follow-up was 3.5 years. Genetic alterations (GA) were noted in 69.6%, with BRAF^V600E (n = 11), and RET-PTC (n = 8) detected only in PTC. GA were detected in 2/7 FTC (1 PAX8-PPARγ, 1 NRAS) and 6/10 FVPTC (3 PAX8-PPARγ, 1 STRN-ALK, 1 BRAF^K601E, 1 NRAS). Patients with BRAF^V600E were predominantly Hispanic (81.8%) and >15 years (81.8%), whereas 87.5% RET-PTC and 50% other-fusions occurred in patients ≤15 years (p = 0.044). Of the 29 PTC patients, 82.8% had GA: BRAF^V600E (37.9%), RET-PTC (27.6%), 17.2% other fusion-oncogenes (2 -ALK, 3 -NTRK). Non-RET fusions had the highest vascular invasion (100%, p = 0.042 vs RET-PTC) and frequent lymphatic invasion (80%). GA were most common in PTC with cervical metastasis.

CONCLUSIONS

BRAF^V600E was the most common single mutation, especially in older and Hispanic adolescents. All fusions combined are more common than BRAF^V600E. NGS reveals a genetic basis in most pediatric WDTC, which may have implications for the role of molecular testing and systemic therapy.

The promise of TRK inhibitors in pediatric cancers with NTRK fusions

NTRK fusions are rare oncogenic drivers that occur across a range of pediatric cancers. These include infantile fibrosarcoma and secretory breast cancer in which such fusions are nearly pathognomonic, and a spectrum of more common pediatric cancers in which NTRK fusions occur at a lower frequency. Within the last 5 years, two TRK inhibitors, larotrectinib and entrectinib, have demonstrated histology-agnostic activity against NTRK fusion driven cancers and achieved FDA approval. Here the data supporting the use of these TRK inhibitors for the treatment of cancers harboring NTRK fusions is reviewed, with a particular focus on the pediatric experience. Mechanisms of acquired resistance to these first generation TRK inhibitors are discussed and investigational second generation TRK inhibitors that may overcome some of these mechanisms of resistance are highlighted.

The BRAFV600E Mutation Is Not a Risk Factor for More Aggressive Tumor Behavior in Radiogenic and Sporadic Papillary Thyroid Carcinoma at a Young Age

Simple Summary

Analysis of the groups of young Ukrainian patients (aged ≤28 years) with radiogenic and sporadic papillary thyroid carcinomas (PTCs) showed that the frequency of BRAF^V600E was increasing with patient age, consistently remaining lower in radiogenic PTCs. In both etiopathogenic groups, the BRAF^V600E-positive PTCs more frequently had a dominant papillary growth pattern, smaller tumor size, higher Ki67 labeling index, and a frequency of the major indicators of tumor invasiveness that is lower than or equal to that of the BRAF^V600E-negative tumors. Comparison of the BRAF^V600E-positive PTCs across the groups found a virtual absence of differences, while the BRAF^V600E-negative tumors differed markedly and displayed a higher frequency of invasive tumor features in the radiogenic PTCs. Hence, there is evidence that BRAF^V600E does not confer a more aggressive course of PTC in young patients regardless of tumor etiology.

Abstract

Histopathological changes in the fusion oncogene-driven papillary thyroid carcinomas (PTCs) from children and adolescents exposed to Chernobyl fallout have been extensively studied. However, characteristics of the radiogenic BRAF^V600E-positive PTCs, whose proportion is growing with time, are not well described yet. We analyzed the relationship between the BRAF^V600E status (determined immunohistochemically with the VE1 antibody) and the clinicopathological features of 247 radiogenic and 138 sporadic PTCs from young Ukrainian patients aged ≤28 years. The frequency of BRAF^V600E was increasing with patient age, consistently remaining lower in radiogenic PTCs. In both etiopathogenic groups, the BRAF^V600E-positive PTCs more frequently had a dominant papillary growth pattern, smaller tumor size, higher Ki67 labeling index, and a frequency of the major indicators of tumor invasiveness that is lower than or equal to that of the BRAF^V600E-negative tumors. Comparison of the BRAF^V600E-positive PTCs across the groups found a virtual absence of differences. In contrast, the BRAF^V600E-negative radiogenic PTCs displayed less frequent dominant papillary and more frequent solid growth patterns, lower Ki67 labeling index, and higher invasiveness than the BRAF^V600E-negative sporadic tumors. Thus, BRAF^V600E is not associated with a more aggressive course of PTC in young patients regardless of etiology. The major clinicopathological differences between the radiogenic and sporadic PTCs are observed among the BRAF^V600E-negative tumors.

Diverse Oncogenic Fusions and Distinct Gene Expression Patterns Define the Genomic Landscape of Pediatric Papillary Thyroid Carcinoma

Pediatric papillary thyroid carcinoma (PPTC) is clinically distinct from adult-onset disease. Although there are higher rates of metastasis and recurrence in PPTC, prognosis remains highly favorable. Molecular characterization of PPTC has been lacking. Historically, only 40% to 50% of childhood papillary thyroid carcinoma (PTC) were known to be driven by genomic variants common to adult PTC; oncogenic drivers in the remainder were unknown. This contrasts with approximately 90% of adult PTC driven by a discrete number of variants. In this study, 52 PPTCs underwent candidate gene testing, followed in a subset by whole-exome and transcriptome sequencing. Within these samples, candidate gene testing identified variants in 31 (60%) tumors, while exome and transcriptome sequencing identified oncogenic variants in 19 of 21 (90%) remaining tumors. The latter were enriched for oncogenic fusions, with 11 nonrecurrent fusion transcripts, including two previously undescribed fusions, STRN-RET and TG-PBF. Most fusions were associated with 3' receptor tyrosine kinase (RTK) moieties: RET, MET, ALK, and NTRK3. For advanced (distally metastatic) tumors, a driver variant was described in 91%. Gene expression analysis defined three clusters that demonstrated distinct expression of genes involved in thyroid differentiation and MAPK signaling. Among RET-CCDC6-driven tumors, gene expression in pediatric tumors was distinguishable from that in adults. Collectively, these results show that the genomic landscape of pediatric PTC is different from adult PTC. Moreover, they identify genomic drivers in 98% of PPTCs, predominantly oncogenic fusion transcripts involving RTKs, with a pronounced impact on gene expression. Notably, most advanced tumors were driven by a variant for which targeted systemic therapy exists. SIGNIFICANCE: This study highlights important distinctions between the genomes and transcriptomes of pediatric and adult papillary thyroid carcinoma, with implications for understanding the biology, diagnosis, and treatment of advanced disease in children.

Major Oncogenic Drivers and Their Clinicopathological Correlations in Sporadic Childhood Papillary Thyroid Carcinoma in Belarus

Childhood papillary thyroid carcinoma (PTC) diagnosed after the Chernobyl accident in Belarus displayed a high frequency of gene rearrangements and low frequency of point mutations. Since 2001, only sporadic thyroid cancer occurs in children aged up to 14 years but its molecular characteristics have not been reported. Here, we determine the major oncogenic events in PTC from non-exposed Belarusian children and assess their clinicopathological correlations. Among the 34 tumors, 23 (67.6%) harbored one of the mutually exclusive oncogenes: 5 (14.7%) BRAFV600E, 4 (11.8%) RET/PTC1, 6 (17.6%) RET/PTC3, 2 (5.9%) rare fusion genes, and 6 (17.6%) ETV6ex4/NTRK3. No mutations in codons 12, 13, and 61 of K-, N- and H-RAS, BRAFK601E, or ETV6ex5/NTRK3 or AKAP9/BRAF were detected. Fusion genes were significantly more frequent than BRAFV600E (p = 0.002). Clinicopathologically, RET/PTC3 was associated with solid growth pattern and higher tumor aggressiveness, BRAFV600E and RET/PTC1 with classic papillary morphology and mild clinical phenotype, and ETV6ex4/NTRK3 with follicular-patterned PTC and reduced aggressiveness. The spectrum of driver mutations in sporadic childhood PTC in Belarus largely parallels that in Chernobyl PTC, yet the frequencies of some oncogenes may likely differ from those in the early-onset Chernobyl PTC; clinicopathological features correlate with the oncogene type.

Transforming approaches to treating TRK fusion cancer: historical comparison of larotrectinib and histology-specific therapies

OBJECTIVE

The results from basket trials utilized to gain regulatory approval of tumor-agnostic therapies can be difficult to interpret without the context of a comparator arm. We describe the role and efficacy of histology-based treatments to provide a historical comparison with larotrectinib.

METHODS

A systematic literature review (SLR) was conducted on the clinical outcomes of current histology-based standard of care treatments used in non-small cell lung cancer, colorectal cancer, thyroid cancer, gliomas, soft tissue sarcoma, salivary gland cancer, and infantile fibrosarcoma (7 of the 21 tumor histologies in the larotrectinib trials). The review focused on advanced stage/metastatic disease to make a historical comparison with larotrectinib.

RESULTS

Larotrectinib provides positive outcomes in both adult and pediatric patients with advanced or metastatic solid tumors known to harbor NTRK gene fusions across a wide range of tumor types. Although the numbers of patients per tumor type are limited, the results of this historical comparison demonstrated that larotrectinib is an efficacious treatment option when naïvely indirectly compared with historical treatments across all 7 reviewed tumor types, especially in comparison to later lines of therapy.

CONCLUSIONS

Utilizing larotrectinib as a case example across these types of historical comparisons shows that larotrectinib provides positive efficacy outcomes in TRK fusion cancer across tumor histologies known to harbor NTRK gene fusions that may be preferable to historical treatments.

Integrated DNA and RNA sequencing reveals targetable alterations in metastatic pediatric papillary thyroid carcinoma

BACKGROUND

Pediatric papillary thyroid carcinoma (PTC) is clinically and biologically distinct from adult PTC. We sequenced a cohort of clinically annotated pediatric PTC cases enriched for high-risk tumors to identify genetic alterations of relevance for diagnosis and therapy.

METHODS

Tumor DNA and RNA were extracted from FFPE tissue and subjected to next-generation sequencing (NGS) library preparation using a custom 124-gene hybridization capture panel and the 75-gene Archer Oncology Research Panel, respectively. NGS libraries were sequenced on an Illumina MiSeq.

RESULTS

Thirty-six pediatric PTC cases were analyzed. Metastases were frequently observed to cervical lymph nodes (29/36, 81%), with pulmonary metastases less commonly found (10/36, 28%). Relapsed or refractory disease occurred in 18 patients (18/36, 50%). DNA sequencing revealed targetable mutations in 8 of 31 tumors tested (26%), most commonly BRAF p.V600E (n = 6). RNA sequencing identified targetable fusions in 13 of 25 tumors tested (52%): RET (n = 8), NTRK3 (n = 4), and BRAF. Mutually exclusive targetable alterations were discovered in 15 of the 20 tumors (75%) with both DNA and RNA analyzed. Fusion-positive PTC was associated with multifocal disease, higher tumor staging, and higher American Thyroid Association risk levels. Both BRAF V600E mutations and gene fusions were correlated with the presence of cervical metastases.

CONCLUSIONS

Targetable alterations were identified in 75% of pediatric PTC cases with both DNA and RNA evaluated. Inclusion of RNA sequencing for detection of fusion genes is critical for evaluation of these tumors. Patients with fusion-positive tumors were more likely to have features of high-risk disease.

BRAF V600E and TERT promoter mutations in paediatric and young adult papillary thyroid cancer and clinicopathological correlation

Objectives The primary objective of this study was to determine the prevalence of BRAF V600E and TERTpromoter mutations in paediatric and young adult patients with papillary thyroid carcinoma (PTC) and the secondary objective, to assess their association with clinicopathological features. Methods Patients ≤20 years who underwent surgery for differentiated thyroid cancer (DTC) from 2005 to 2018 were consecutively enrolled for BRAF V600E and TERTpromoter mutations analysis and records analysed for the association of aggressive features. Univariate analysis and multivariate logistic regression were used to identify the independent predictors of BRAF V600E mutations. Results Among 100 patients with DTC, 68 patients were ≤18 years and the remaining 30 patients were >18 years of age with a median age of 17 years (IQR 14-19 years) 98 patients had PTC and 2 had FTC. BRAF V600E mutation was present in 14/98 (14.3%) PTC and TERTpromoter mutation noted in none. Multivariate analysis identified RAI refractoriness (OR:10.57, 95% CI: 2.6 to 41.6, P-0.0008) as an independent factor associated with BRAF V600E mutation. 17 patients with distant metastases were negative for both BRAF V600E or TERTpromoter mutation. No significant association was observed between age, gender, PTC variants, extra-thyroidal extension, lymphovascular invasion, multifocality, RAI administration and event rate with BRAF V600E mutation. Irrespective of BRAF V600E mutation, radioiodine refractory status (p-0.0001) had a reduced EFS probability. Conclusion In paediatric & young adult PTC, TERTpromoter mutation is absent and BRAFV600E mutation is not associated with distant metastasis. The prevalence rate of the BRAF V600E mutation is much lower compared to adult PTC patients.

Genetic Alterations in Pediatric Thyroid Cancer Using a Comprehensive Childhood Cancer Gene Panel

CONTEXT

Pediatric differentiated thyroid cancer (DTC) differs from adult DTC in its underlying genetics and clinicopathological features. In this report, we studied these aspects in 48 cases of pediatric DTC.

PATIENTS AND METHODS

We used the comprehensive Oncomine Childhood Cancer Gene panel on Ion Torrent next-generation sequencing platform. We included 48 patients (37 girls and 11 boys) with pediatric DTC (median age 17 years; range, 5-18 years) and studied the association between these genetic alterations and the clinicopathological features and outcome.

RESULTS

Of 48 tumors, 33 (69%) had somatic genetic alterations that were mutually exclusive except in one tumor. BRAFV600E and RET-PTC1 were the most common, occurring in 9 different tumors (19%) each. RET-PTC3 and ETV6-NTRK3 were the next most common, with each occurring in 4 different tumors (8%). Other genetic alterations including EML4-NTRK1, EML4-ALK, NRAS, KRAS, PTEN, and CREBBP occurred once each. There were no differences between those who had mutations and those without mutations with respect to age, sex, tumor multifocality, extrathyroidal extension, vascular invasion, lymph node or distant metastasis, and American Thyroid Association response to therapy status at the last follow-up visits. Similarly, none of these factors was different between those with fusion genes vs single-point mutations vs no mutations.

CONCLUSIONS

In pediatric DTC, fusion genes are more common than single-point mutations. The most common genetic alterations are RET-PTC1, BRAFV600E, RET-PTC3, and ETV6-NTRK3. Other alterations occur rarely. Genetic alterations do not correlate with the clinicopathological features or the outcome.

Predominant DICER1 Pathogenic Variants in Pediatric Follicular Thyroid Carcinomas

Background: Pediatric thyroid cancer has characteristics that are distinct from adulthood thyroid cancer. Due to its very low prevalence, little is known about the genetic characteristics of pediatric follicular thyroid cancer (FTC). Methods: We investigated genetic alterations in tumor tissues from 15 patients aged <20 years (median: 14.3 years; range: 2.4 - 19.0 years) using multifaceted approaches. Whole-exome sequencing, targeted next-generation sequencing using a cancer gene panel, and Sanger sequencing of the major exons of the H/K/N-RAS and DICER1 genes and the promoter region of the TERT gene were performed. Normal tissues or blood of patients with DICER1- or PTEN-positive tumors was also evaluated to determine whether the variant is germ line. Results: The median tumor size was 3.1 cm (range: 0.6 - 6.4 cm). Four patients exhibited angioinvasion and one extensive capsular invasion; none showed evidence of disease over a median of 8.1 years. Eight patients (53.3%) had DICER1 variants, including four with DICER1 syndrome (three patients were <10 years of age). One patient had a germ line PTEN frameshift variant with the diagnosis of PTEN hamartoma tumor syndrome. One patient had a PAX8/PPARγ rearrangement, and two patients had no genetic driver alteration other than multiple loss of heterozygosity with or without copy number alterations in their tumors. No RAS or TERT variants were found. Nodular hyperplasia and follicular adenoma (FA) coexisted in DICER1 variant-positive FTCs more frequently than variant-negative FTCs (p = 0.026). All DICER1 variant-positive FTCs had a somatic missense variant at metal binding sites (six at codon p.E1813 and two at codon p.D1709) within the RNase IIIb domain; seven had other missense, nonsense, or frameshift variants in the DICER1 gene. Six coexisting FAs of two patients with DICER1 syndrome (three of each) had additional somatic variants at metal binding sites within the RNase IIIb domain (codon p.E1705, p.D1709, p.D1810, or p.E1813), different from each other and from the indexed FTC tumor. Conclusions: Pediatric FTCs have distinct genomic alterations and pathogenesis compared with adults, particularly those characterized by DICER1 variants. The DICER1 variant should be considered in pediatric FTCs, especially in cases <10 years of age. In all DICER1 variant-positive FTCs and FAs, recurrent hotspot variants were found at metal binding sites within the RNase IIIb domain, suggesting they impact tumorigenesis.

The application of current classification systems in pediatric cytopathology: Perspectives from the pediatric cytopathology symposium at the 20th International Congress of Cytology 2019

A pediatric cytopathology symposium was held at the recent 20th International Congress of Cytology, which convened in Sydney, Australia, in May 2019. This educational event brought together cytopathologists from different countries and different institutions to discuss some of the practical considerations when applying current diagnostic classification systems to cytopathology specimens from young (pediatric and adolescent) patients. Within the past decade, various classification systems have been developed to create more standardized terminology for cytopathology specimen reporting among institutions, which can lead to improved management guidelines based on evidence-based medicine. It is well known that a majority of the peer-reviewed publications in cytopathology discussing the usefulness of these classification schemes predominantly contain case cohorts of adult patients. Although pediatric cases are not excluded from following these diagnostic guidelines, there is less of an emphasis on this age group with respect to unique findings and management differences. Thus, discussing the role of these guidelines and their applications in pediatric cases at an international educational gathering can not only be beneficial in educating the cytopathology community about the value of applying these classification systems to pediatric populations, but also can raise awareness of unique entities in cytologic specimens obtained from young patients.

Thyroid Cancer in the Pediatric Population

Thyroid cancer is rare in the pediatric population, but thyroid carcinomas occurring in children carry a unique set of clinical, pathologic, and molecular characteristics. In comparison to adults, children more often present with aggressive, advanced stage disease. This is at least in part due to the underlying biologic and molecular differences between pediatric and adult thyroid cancer. Specifically, papillary thyroid carcinoma (which accounts for approximately 90% of pediatric thyroid cancer) has a high rate of gene fusions which influence the histologic subtypes encountered in pediatric thyroid tumors, are associated with more extensive extrathyroidal disease, and offer unique options for targeted medical therapies. Differences are also seen in pediatric follicular thyroid cancer, although there are few studies of non-papillary pediatric thyroid tumors published in the literature due to their rarity, and in medullary carcinoma, which is most frequently diagnosed in the pediatric population in the setting of prophylactic thyroidectomies for known multiple endocrine neoplasia syndromes. The overall shift in the spectrum of histotypes and underlying molecular alterations common in pediatric thyroid cancer is important to recognize as it may directly influence diagnostic test selection and therapeutic recommendations.

AGK-BRAF is associated with distant metastasis and younger age in pediatric papillary thyroid carcinoma

BACKGROUND

The incidence of thyroid carcinoma has increased in most populations, including pediatric patients. The increase is almost exclusively due to an increase in the incidence of papillary thyroid carcinoma (PTC). Genetic alterations leading to mitogen-activated protein kinase (MAPK) pathway activation are highly prevalent in PTC, with BRAF V600E mutation being the most common event in adult PTC. Although a lower prevalence of BRAF V600E had been reported among pediatric patients, a higher prevalence of BRAF fusion has been identified in both radiation-exposed and sporadic pediatric PTC. However, little is known about the prognostic implications of BRAF fusions in pediatric PTC.

PROCEDURE

In this study, we investigated the prevalence of BRAF alterations (AGK-BRAF fusion and BRAF V600E mutation) in a large set of predominantly sporadic pediatric PTC cases and correlate with clinicopathological features. Somatic AGK-BRAF fusion was investigated by RT-PCR and confirmed by FISH break-apart. The BRAF V600E mutation was screened using Sanger sequencing.

RESULTS

AGK-BRAF fusion, found in 19% of pediatric PTC patients, was associated with distant metastasis and younger age. Conversely, the BRAF V600E, found in 15% of pediatric PTC patients, was correlated with older age and larger tumor size.

CONCLUSION

Collectively, our results advance knowledge concerning genetic bases of pediatric thyroid carcinoma, with potential implications for diagnosis, prognosis, and therapeutic approaches.

TRK Fusion Cancers in Children: A Clinical Review and Recommendations for Screening

Chromosomal translocations involving the NTRK1, NTRK2, and NTRK3 genes (TRK fusions), which encode the neurotrophin tyrosine kinase receptors TRKA, TRKB, and TRKC, can result in constitutive activation and aberrant expression of TRK kinase. Certain cancers almost universally harbor TRK fusions, including infantile fibrosarcoma, cellular congenital mesoblastic nephroma, secretory breast cancer, and mammary analog secretory carcinoma of the salivary gland. TRK fusions have also been identified at lower frequencies across a broad range of other pediatric cancers, including undifferentiated sarcomas, gliomas, papillary thyroid cancers, spitzoid neoplasms, inflammatory myofibroblastic tumors, and acute leukemias. Here we review the prevalence and diseases associated with TRK fusions and methods of detection of these fusions in light of the recent development of selective TRK inhibitors, such as larotrectinib, which demonstrated a 75% response rate across children and adults with TRK fusion cancers. We provide recommendations for screening pediatric tumors for the presence of TRK fusions, including the use of immunohistochemistry or fluorescence in situ hybridization for patients with tumors likely to harbor TRK fusions. Further, we recommend next-generation sequencing for tumors that have a relatively low prevalence of TRK fusions, both to identify patients who may benefit from TRK inhibition and to identify other targetable oncogenic drivers that exist in the same tumor types.

Role of ultrasonographic features and quantified BRAFV600E mutation in lymph node metastasis in Chinese patients with papillary thyroid carcinoma

The association between cervical lymph node metastasis (LNM) and ultrasonographic features as well as BRAF^V600E mutations in patients with papillary thyroid carcinoma (PTC) remained controversial. This study investigated the association between LNM and ultrasonographic features as well as BRAF^V600E mutation in Chinese patients with PTC. A total of 280 patients with PTC in China were included in this study. 108 had cervical lymph node metastasis, while 172 had not. Younger age (<45years) and several ultrasonographic features were significantly associated with cervical LNM (Ps < 0.05). The BRAF^V600E mutation was detected in 81.0% of patients with PTC (226/280). The status of BRAF^V600E mutation was not associated with cervical LNM. However, Ct values by PCR and intensity of reactions by immunohistochemistry (IHC) for BRAF^V600E expression had shown significant difference between group with and without LNM. Furthermore, an increased proportion of LNM was also found with the incremental intensity of IHC for BRAF^V600E expression from weak to strong reaction after adjusted potential confounders. Further studies are required to verify this association and explore the intrinsic mechanism.

RET EXPRESSION AND ITS CORRELATION WITH CLINICOPATHOLOGIC DATA IN PAPILLARY THYROID CARCINOMA

SUMMARY – The purpose of this study was to analyze the possible prognostic value of RET mutation in papillary thyroid carcinoma and its incidence in the past few decades in our population, due to the increasing incidence of papillary thyroid carcinoma. The present study included 180 patients operated for papillary thyroid carcinoma. The clinical and histopathologic characteristics were analyzed. Paraffin sections of the selected histologic slides were cut again and immunohistochemically stained by the Clone 3F8 P (HIER) from Novocastra (Vision Bio Systems Europe, Newcastle upon Tyne, UK) monoclonal antibody to RET oncoprotein. Univariate analysis indicated sex (p=0.01), histologic subtype (p=0.075) and capsular invasion (p=0.010) to be statistically significant predictors of lymph node metastases, whereas age (p=0.796), tumor size (p=0.556) and intraglandular dissemination (p=0.131) showed no such correlation. The presence of RET mutation (p=0.704) was not a statistically significant predictor of the tumor metastasizing potential. RET mutation (p=0.500) showed no statistically significant correlation with papillary thyroid carcinoma classifed into prognostic groups according to clinicopathologic features either. RET mutation was detected in 30% of 180 papillary thyroid carcinomas. This is the first large study demonstrating that RET mutation incidence in papillary thyroid carcinoma in Croatian population is consistent with the classic distribution of sporadic cases, despite the increased prevalence of papillary thyroid carcinoma in the past few decades.

Predictive Value of BRAFV600E Mutation for Lymph Node Metastasis in Papillary Thyroid Cancer: A Meta-analysis

BRAF^V600E mutation has been thought to be a valuable molecular marker that may predict a worse prognosis for papillary thyroid cancer (PTC). But whether BRAF^V600E mutation is associated with lymph node metastasis (LNM) remains controversial. Different surgical strategies may bring a bias in demonsstrating the association between them. In order to delineate a risk stratification to guide a tailored initial approach to tumors that express BRAF^V600E mutation, we performed this meta-analysis by using the articles in which total or near-total thyroidectomy plus bilateral central lymph node dissection was routinely performed to avoid the bias from the surgical strategy. We searched the Medline, Embase and CNKI database for eligible studies from January 2003 to May 2018. Meta-analysis was performed using the STATA 12.0 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated under fixed-effects or randomeffects models. Fifteen clinical studies were included with a total of 4909 PTC patients. Our meta-analysis results reported that BRAFV600E mutation was associated with LNM (OR=1.34; 95% CI: 1.09-1.65; P=0.005), as well as central LNM (OR=1.59; 95% CI: 1.35-1.88; P<0.00001). Moreover, in patients with papillary thyroid microcarcinoma, we also confirmed the predictive value of BRAF^V600E mutation for LNM (OR=3.49; 95% CI: 2.02-6.02; P<0.00001). This meta-analysis demonstrates that BRAF^V600E mutation is closely related to LNM in PTC patients. The results suggest that BRAF^V600E mutation can be considered as a risk factor for LNM in PTC. Moreover, combining BRAF^V600E mutation with other risk factors to determine the initial surgical treatment may bring benefits for PTC patients.

65 YEARS OF THE DOUBLE HELIX: Endocrine tumour syndromes in children and adolescents

As medicine is poised to be transformed by incorporating genetic data in its daily practice, it is essential that clinicians familiarise themselves with the information that is now available from more than 50 years of genetic discoveries that continue unabated and increase by the day. Endocrinology has always stood at the forefront of what is called today 'precision medicine': genetic disorders of the pituitary and the adrenal glands were among the first to be molecularly elucidated in the 1980s. The discovery of two endocrine-related genes, GNAS and RET, both identified in the late 1980s, contributed greatly in the understanding of cancer and its progression. The use of RET mutation testing for the management of medullary thyroid cancer was among the first and one of most successful applications of genetics in informing clinical decisions in an individualised manner, in this case by preventing cancer or guiding the choice of tyrosine kinase inhibitors in cancer treatment. New information emerges every day in the genetics or system biology of endocrine disorders. This review goes over most of these discoveries and the known endocrine tumour syndromes. We cover key genetic developments for each disease and provide information that can be used by the clinician in daily practice.

Anaplastic lymphoma kinase (ALK) gene rearrangements in radiation-related human papillary thyroid carcinoma after the Chernobyl accident

Childhood radiation exposure has been associated with increased papillary thyroid carcinoma (PTC) risk. The role of anaplastic lymphoma kinase (ALK) gene rearrangements in radiation‐related PTC remains unclear, but STRN‐ALK fusions have recently been detected in PTCs from radiation exposed persons after Chernobyl using targeted next‐generation sequencing and RNA‐seq. We investigated ALK and RET gene rearrangements as well as known driver point mutations in PTC tumours from 77 radiation‐exposed patients (mean age at surgery 22.4 years) and PTC tumours from 19 non‐exposed individuals after the Chernobyl accident. ALK rearrangements were detected by fluorescence in situ hybridisation (FISH) and confirmed with immunohistochemistry (IHC); point mutations in the BRAF and RAS genes were detected by DNA pyrosequencing. Among the 77 tumours from exposed persons, we identified 7 ALK rearrangements and none in the unexposed group. When combining ALK and RET rearrangements, we found 24 in the exposed (31.2%) compared to two (10.5%) in the unexposed group. Odds ratios increased significantly in a dose‐dependent manner up to 6.2 (95%CI: 1.1, 34.7; p = 0.039) at Iodine‐131 thyroid doses >500 mGy. In total, 27 cases carried point mutations of BRAF or RAS genes, yet logistic regression analysis failed to identify significant dose association. To our knowledge we are the first to describe ALK rearrangements in post‐Chernobyl PTC samples using routine methods such as FISH and IHC. Our findings further support the hypothesis that gene rearrangements, but not oncogenic driver mutations, are associated with ionising radiation‐related tumour risk. IHC may represent an effective method for ALK‐screening in PTCs with known radiation aetiology, which is of clinical value since oncogenic ALK activation might represent a valuable target for small molecule inhibitors.

Molecular testing of BRAF, RAS and TERT on thyroid FNAs with indeterminate cytology improves diagnostic accuracy

OBJECTIVE

Liquid-based (LB)-FNA is widely recognized as a reliable diagnostic method to evaluate thyroid nodules. However, up to 30% of LB-FNA remain indeterminate according to the Bethesda system. Use of molecular biomarkers has been recommended to improve its pathological accuracy but implementation of these tests in clinical practice may be difficult. Here, we evaluated feasibility and performance of molecular profiling in routine practice by testing LB-FNA for BRAF, N/HRAS and TERT mutations.

METHODS

We studied a large prospective cohort of 326 cases, including 61 atypia of undetermined significance, 124 follicular neoplasms, 72 suspicious for malignancy and 69 malignant cases. Diagnosis of malignancy was confirmed by histology on paired surgical specimen.

RESULTS

Mutated LB-FNAs were significantly associated with malignancy regardless of the cytological classification. Overall sensitivity was 60% and specificity 89%. Importantly, in atypia of undetermined significance and follicular neoplasm patients undergoing surgery according to the Bethesda guidelines, negative predictive values were 85.4% and 90% respectively. TERT promoter mutation was rare but very specific for malignancy (5.5%) suggesting that it could be of interest in patients with indeterminate cytology.

CONCLUSIONS

Mutation profiling can be successfully performed on thyroid LB-FNA without any dedicated sample in a pathology laboratory. It is an easy way to improve diagnostic accuracy of routine LB-FNA and may help to better select patients for surgery and to avoid unnecessary thyroidectomies.

Role of molecular markers to predict distant metastasis in papillary thyroid carcinoma: Promising value of TERT promoter mutations and insignificant role of BRAF mutations—a meta-analysis

The presence of distant metastasis is associated with an adverse outcome in papillary thyroid cancer. We performed a meta-analysis to investigate the role of molecular markers as predictors for distant metastasis in papillary thyroid cancer. Four electronic databases including PubMed, Web of Science, Scopus, and Virtual Health Library were searched, and odds ratio and its 95% confidence interval concerning the association of BRAF, RAS, and TERT promoter mutations and RET/PTC rearrangements with distant metastasis were calculated using random-effects model. In total, 42 studies with 11,109 papillary thyroid cancers were included for meta-analyses. Overall, the presence of TERT promoter (odds ratio = 5.95; 95% confidence interval = 2.95–11.99), RAS mutations (odds ratio = 2.5; 95% confidence interval = 1.00–6.22), and RET/PTC rearrangements (odds ratio = 1.92; 95% confidence interval = 1.03–3.56) were found to be associated with a significantly increased risk for distant metastasis. BRAF mutations were not associated with an elevated risk for distant metastasis (odds ratio = 0.79; 95% confidence interval = 0.54–1.16). In conclusion, our study demonstrated the promising value of few molecular biomarkers, especially TERT promoter mutations in predicting distant metastasis in papillary thyroid cancers, while BRAF mutations showed no association with distant metastasis. Our study affirms the value of selected mutations for tumor risk stratification and assessment of patients’ prognosis.

Clinicopathological Characteristics of Papillary Thyroid Cancer in Children with Emphasis on Pubertal Status and Association with BRAFV600E Mutation

OBJECTIVE

Papillary thyroid cancer (PTC) may behave differently in prepubertal children as compared to pubertal children and adults. BRAF gene activating mutations may associate with PTC by creating aberrant activation. We aimed to evaluate the clinicopathological characteristics of PTC patients with emphasis on the pubertal status and also to investigate the association of BRAF^V600E mutation with disease characteristics.

METHODS

The medical records of 75 patients with PTC were reviewed retrospectively. BRAF^V600E mutation status was available only in the medical records of 56 patients.

RESULTS

Mean age at diagnosis was 12.4±3.8 years. There was no difference in sex, initial signs, tumor histopathology, and pathological evidence of tumor aggressiveness between prepubertal and pubertal children. Although not statistically significant, lateral neck nodal metastasis and lung metastasis at diagnosis were more prevalent in prepubertal children. After excluding patients with microcarcinoma, prepubertal children were found to require lateral neck dissection and further doses of radioactive iodine more frequently than pubertal patients. Recurrence was also more frequent in prepubertal children (p=0.016). Frequency of BRAF^V600E mutation was similar in prepubertal and pubertal patients. BRAF^V600E mutation was found in 14/56 (25%) patients and was high in the classic variant PTC (p=0.004). Multicentricity was high in BRAF^V600E mutation (p=0.01). There was no relation between BRAF^V600E mutation and lymph node and pulmonary metastasis at diagnosis, or between BRAF^V600E mutation and pathological evidence of tumor aggressiveness.

CONCLUSION

PTC is more disseminated in prepubertal children. BRAF^V600E mutation does not correlate with a more extensive or aggressive disease. BRAF^V600E mutation is not the cause of the differences in the biological behavior of PTC in prepubertal and pubertal children.

Association between BRAF V600E Mutation and Ultrasound Features in Papillary Thyroid Carcinoma Patients with and without Hashimoto's Thyroiditis

To assess the association between BRAF V600E mutation and ultrasound (US) features in papillary thyroid carcinoma (PTC) patients with and without Hashimoto’s thyroiditis (HT). We retrospectively reviewed the US features and status of BRAF V600E mutation in 438 consecutive patients with surgically confirmed PTCs. The association between BRAF mutation and US features were analyzed. In addition, we conducted subgroup analyses in terms of coexistent HT. The BRAF mutation was found in 86.5% of patients (379 of 438). Patient age (OR: 1.028, P = 0.010), age ≥ 50 y (OR: 1.904, P = 0.030), and microcalcification (OR: 2.262, P = 0.015) on US were significantly associated with BRAF mutation in PTC patients. Solid component (OR: 5.739, P = 0.019) on US was the significant predictor for BRAF mutation in patients with HT, while age (OR: 1.036, P = 0.017) and microcalcification (OR: 3.093, P = 0.017) were significantly associated with BRAF mutation in patients without HT. In conclusion, older age and microcalcification are risk factors for BRAF mutation in PTC patients, especially in those without HT. For those with HT, however, PTCs with BRAF mutation tend to be solid on ultrasound. These factors might be considered when making treatment planning or prognosis evaluation.

Correlation between BRAF V600E mutation and clinicopathological features in pediatric papillary thyroid carcinoma

In adults, the presence of the BRAF ^V600E mutation in papillary thyroid cancer (PTC) has been demonstrated to be strongly associated with aggressive cancer-cell characteristics and poor patient prognosis. In contrast, the frequency of this mutation in pediatric PTC has undergone limited study, and the few available estimates range from 0 to 63%. Furthermore, the role of the BRAF ^V600E mutation in pediatric PTC is controversial; thus, the present study aimed to investigate the prevalence and role of the BRAF ^V600E mutation in 48 pediatric patients with PTC, aged 3-13 years. Of these patients, 41 were diagnosed with classic PTC, five were found to have a follicular variant of PTC, and two to exhibit a diffuse sclerosing PTC variant. The BRAF ^V600E mutation was identified to be present in 35.4% of the 48 analyzed patients, and in 41.5% of the patients diagnosed with classical PTC. Furthermore, the presence of the BRAF ^V600E mutation was found to be associated with a patient age at diagnosis of less than ten years (P=0.011), the performance of a thyroidectomy (P=0.03), exhibited tumor multifocality (P=0.02) and/or extra-thyroidal invasion (P=0.003), and both a low MACIS (Metastases, Age, Completeness of resection, Invasion, Size)(P=0.036) and AMES (Age, Metastasis, Extent of tumor, Size)(P=0.001) score. Together, these data suggest that the presence of the BRAF ^V600E mutation may be negatively correlated with partial aggressive clinicopathological features of pediatric PTC.

Molecular Genetics of Thyroid Cancer in Children and Adolescents

There has been a steady incorporation of powerful new molecular tools into the evaluation and management of thyroid nodules and thyroid cancer. With an increasing incidence of nodules and differentiated thyroid cancer (DTC) being diagnosed in children and adolescents, oncogene data are providing insight into the clinical differences between pediatric and adult patients with histologically similar DTC. However, additional investment and efforts are needed to define the genomic landscape for pediatric DTC with the goal of improving preoperative diagnostic accuracy as well as stratifying treatment in an effort to reduce complications of therapy.

Frequent BRAF V600E and Absence of TERT Promoter Mutations Characterize Sporadic Pediatric Papillary Thyroid Carcinomas in Japan

Pediatric papillary thyroid carcinoma (PTC) has unique features but requires further genetic investigation. Moreover, there has been increasing concern about the risk for pediatric PTC in Japan after the Fukushima accident. This study aims to evaluate the frequencies of BRAF and TERT promoter mutations and to examine their significance in non-radiation-associated pediatric PTCs in Japan. We enrolled 81 pediatric PTC patients aged ≤20 years. The control group included 91 adult PTCs from patients >20 years old. BRAF and TERT mutations were analyzed by allele-specific-PCR and/or Sanger sequencing. Compared with adult PTCs, pediatric PTCs exhibited larger tumor size, more frequent lymph node metastasis, and less classical histology. The prevalence of BRAF ^V600E in pediatric PTCs was 54% and significantly lower than that in adults of 85%. In the pediatric PTCs, BRAF ^V600E was positively associated with older age, classical histology, and the lymph node metastasis but independent from other clinicopathological factors. TERT mutations were identified in 13% of adults and in none of the pediatric PTCs. In conclusion, pediatric PTCs are characterized by more advanced clinicopathological features, lower BRAF ^V600E frequency, and absence of TERT mutation. The BRAF ^V600E frequency in this study is similar to the reported BRAF ^V600E frequency in the ultrasonographically screened pediatric PTCs in Fukushima.

Indications and extent of central neck dissection for papillary thyroid cancer: An American Head and Neck Society Consensus Statement

BACKGROUND

The primary purposes of this interdisciplinary consensus statement were to review the relevant indications for central neck dissection (CND) in patients with papillary thyroid cancer (PTC) and to outline the appropriate extent and relevant techniques required to accomplish a safe and effective CND.

METHODS

A writing group convened by the American Head and Neck Society (AHNS) Endocrine Committee was tasked with identifying the important clinical elements to consider when managing the central neck compartment in patients with PTC based on available evidence in the literature, and the group's collective experience. The position statement paper was then submitted to the full Endocrine Committee, Education Committee, and AHNS Council.

RESULTS

This consensus statement was developed to inform the clinical decision-making process when managing the central neck compartment in patients with PTC from the AHNS. This document is intended to provide clarity through definitions as well as a basic guideline from which to manage the central neck. It is our hope that this improves the quality and reduces variation in management of the central neck, facilitates communication, and furthers research for patients with thyroid cancer.

CONCLUSION

This represents, in our opinion, contemporary optimal surgical care for this patient population and is endorsed by the American Head and Neck Society. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1269-1279, 2017.

Radiation exposure and thyroid cancer: a review

The association between radiation exposure and the occurrence of thyroid cancer has been well documented, and the two main risk factors for the development of a thyroid cancer are the radiation dose delivered to the thyroid gland and the age at exposure. The risk increases after exposure to a mean dose of more than 0.05-0.1 Gy (50-100mGy). The risk is more important during childhood and decreases with increased age at exposure, being low in adults. After exposure, the minimum latency period before the appearance of thyroid cancers is 5 to 10 years. Papillary carcinoma (PTC) is the most frequent form of thyroid carcinoma diagnosed after radiation exposure, with a higher prevalence of the solid subtype in young children with a short latency period and of the classical subtype in cases with a longer latency period after exposure. Molecular alterations, including intra-chromosomal rearrangements, are frequently found. Among them, RET/PTC rearrangements are the most frequent. Current research is directed on the mechanism of genetic alterations induced by radiation and on a molecular signature that can identify the origin of thyroid carcinoma after a known or suspected exposure to radiation.

Pediatric, Adolescent, and Young Adult Thyroid Carcinoma Harbors Frequent and Diverse Targetable Genomic Alterations, Including Kinase Fusions

BACKGROUND

Thyroid carcinoma, which is rare in pediatric patients (age 0-18 years) but more common in adolescent and young adult (AYA) patients (age 15-39 years), carries the potential for morbidity and mortality.

METHODS

Hybrid-capture-based comprehensive genomic profiling (CGP) was performed prospectively on 512 consecutively submitted thyroid carcinomas, including 58 from pediatric and AYA (PAYA) patients, to identify genomic alterations (GAs), including base substitutions, insertions/deletions, copy number alterations, and rearrangements. This PAYA data series includes 41 patients with papillary thyroid carcinoma (PTC), 3 with anaplastic thyroid carcinoma (ATC), and 14 with medullary thyroid carcinoma (MTC).

RESULTS

GAs were detected in 93% (54/58) of PAYA cases, with a mean of 1.4 GAs per case. In addition to BRAF V600E mutations, detected in 46% (19/41) of PAYA PTC cases and in 1 of 3 AYA ATC cases, oncogenic fusions involving RET, NTRK1, NTRK3, and ALK were detected in 37% (15/41) of PAYA PTC and 33% (1/3) of AYA ATC cases. Ninety-three percent (13/14) of MTC patients harbored RET alterations, including 3 novel insertions/deletions in exons 6 and 11. Two of these MTC patients with novel alterations in RET experienced clinical benefit from vandetanib treatment.

CONCLUSION

CGP identified diverse clinically relevant GAs in PAYA patients with thyroid carcinoma, including 83% (34/41) of PTC cases harboring activating kinase mutations or activating kinase rearrangements. These genomic observations and index cases exhibiting clinical benefit from targeted therapy suggest that young patients with advanced thyroid carcinoma can benefit from CGP and rationally matched targeted therapy. The Oncologist 2017;22:255-263 IMPLICATIONS FOR PRACTICE: The detection of diverse clinically relevant genomic alterations in the majority of pediatric, adolescent, and young adult patients with thyroid carcinoma in this study suggests that comprehensive genomic profiling may be beneficial for young patients with papillary, anaplastic, or medullary thyroid carcinoma, particularly for advanced or refractory cases for which clinical trials involving molecularly targeted therapies may be appropriate.

Single Point Mutations in Pediatric Differentiated Thyroid Cancer

PURPOSE

Differentiated thyroid cancer (DTC) is rare in children. Previous studies have suggested that it has different clinicopathologic features and mutation profiles compared with adult DTC. However, those studies focused on a single or limited number of gene mutations. This study comprehensively investigated a large series of pediatric DTC for single point mutations in BRAF, HRAS, KRAS, NRAS, PIK3CA, PTEN, and TERT. It also analyzed associations between clinicopathologic features and the BRAF^V600E mutation.

PATIENTS AND METHODS

Eighty-nine consecutive cases seen in children and adolescents (≤18 years) during 1998-2015 were identified. Rare variants of DTC were excluded, and the study focused on 72 (91.1%) classical papillary thyroid carcinoma (PTC) and seven (8.9%) follicular variant PTC. These included 68 (86.1%) females and 11 (13.9%) males, with a median age of 15.5 years (range 8-18 years). The clinical and histopathological data were obtained from medical records. DNA was extracted from paraffin-embedded tumor tissue, and was PCR-amplified and directly sequenced.

RESULTS

Mutations detected included BRAF^V600E in 19/72 (26.4%) classical PTC samples, and in none of seven follicular variant PTC. Other mutations included: 1/78 (1.3%) successfully amplified tumor samples with TERT^C228T; 2/79 (2.5%) NRAS 61 (c.181C>A and c.182A>G); 1/73 (1.4%) PIK3CA exon 9 (c.1589A>G and c.1598C>T in one tumor); 1/79 (1.3%) PIK3CA exon 20 (c.2951G>A); and 1/74 (1.4%) PTEN exon 5 (c.295G>A). No mutation was found in HRAS, KRAS, NRAS12, PTEN exons 6, 7, and 8, and TERT^C250T. No significant association was found between BRAF^V600E mutation and sex, extrathyroidal invasion, tumor multifocality, vascular invasion, lymph node or distant metastases, and persistent/recurrent disease.

CONCLUSIONS

In pediatric DTC, the prevalence of the BRAF^V600E mutation is significantly less common compared with adult DTC, and there is no association between this mutation and the histopathological features and outcome of PTC. PIK3CA, PTEN, NRAS 61, and TERT^C228T mutations are rare.

Fusion Oncogenes Are the Main Genetic Events Found in Sporadic Papillary Thyroid Carcinomas from Children

BACKGROUND

Previous studies reported significant differences in the clinical presentation and outcomes of papillary thyroid carcinoma (PTC) in pediatric patients compared with adults. Previous studies have suggested that the clinicopathological differences observed between pediatric and adult PTCs may be due the existence of distinct genetic alterations. However, the knowledge of genetic events in pediatric PTCs is based primarily on studies in radiation-exposed PTCs or in the few studies that enrolled predominantly adolescent patients. The aim of this study was to characterize the known oncogenic alterations of the MAPK pathway found in adult and radiation-exposed PTCs in a cohort of predominantly sporadic pediatric PTC patients.

METHODS

Thirty-five pediatric PTCs were screened for the most prevalent fusions (RET/PTC1, RET/PTC2, RET/PTC3, ETV6-NTRK3, and AGK-BRAF) and point mutations (BRAFV600E and NRASQ61) described in sporadic pediatric PTCs. The mutational status was correlated with clinicopathological data.

RESULTS

Mutations were found in 20 out of 35 (57%) PTC cases. Fusion oncogenes were the main genetic alterations found. RET/PTC1-3 rearrangements were found in 13 (37%), ETV6-NTRK3 in 3 (9%), AGK-BRAF in 4 (11%), and BRAFV600E in 3 (9%). No mutation was found in NRASQ61. BRAFV600E was associated with older age and larger tumor size (p < 0.05), and RET/PTC3 was associated with a larger tumor size and multifocality (p < 0.05).

CONCLUSIONS

The genetic signature in this cohort was remarkably different than that observed in adults. Although observed at a lower prevalence, the spectrum of mutations was quite similar to that described in radiation-exposed pediatric PTCs. As mutations were unidentifiable in over 40% of the PTC cases, more comprehensive studies conducted in these patients will help to decipher the genetic landscape of sporadic pediatric PTCs.

Mutation in BRAF and Other Members of the MAPK Pathway in Papillary Thyroid Carcinoma in the Pediatric Population

CONTEXT

Papillary thyroid carcinoma (PTC) is an uncommon tumor in the pediatric population. A limited number of studies have examined genetic mutations affecting the mitogen-activated protein kinase (MAPK) pathway in the pediatric population.

OBJECTIVE

To examine mutations affecting this pathway in PTC in our pediatric population and compare the BRAF V600E mutation rates in pediatric and adult tumors.

DESIGN

Eighty-four patients, including 14 pediatric and 70 adult, with PTC were tested for the BRAF V600E mutation by using real-time polymerase chain reaction and sequencing. Additionally, we examined the rate of RAS point mutations with real-time polymerase chain reaction and rearrangements of RET/PTC1 and RET/PTC3 in the pediatric group with fluorescence in situ hybridization. Clinical and histologic data were compared as well.

RESULTS

Of 77 tumors that had an interpretable result, the BRAF V600E mutant was identified in 4 of 13 pediatric patients (31%) and 43 of 64 adult patients (67%), which was a significant difference (using Fisher exact test, P = .03). One pediatric and 6 adult cases did not reveal an interpretable result with melting curve analysis. One of these cases harbored a rare 3-base pair deletion mutation (c.1799_1801delTGA). Mutations in RAS genes were not seen in any pediatric tumors. One tumor with a RET/PTC1 rearrangement and another with RET/PTC3 were identified in the pediatric population (15%).

CONCLUSIONS

The rate of the BRAF V600E mutation in the pediatric population is significantly lower than that seen in the adult population. Mutations in RAS do not contribute significantly to pediatric PTC. This experience from our institution adds to the growing body of knowledge regarding tumor genetics in pediatric PTC.

Thyroid Carcinoma Pattern Presentation According to Age

Introduction Patients with thyroid cancer in different age groups present with different prognosis.

Objective The objective of this study is to analyze the clinicopathological pattern of thyroid carcinoma presentation according to age groups.

Methods This is a retrospective study. From 2000 to 2010, 623 patients underwent thyroidectomy for cancer in our institution, with 596 enrolled. Patients were divided into groups of 10 years and then in four age subgroups (≤ 24, 25–44, 45–64, and ≥65 years) for statistical analysis. We compared age, gender, and histopathological characteristics between groups.

Results Individuals belonging to the earlier age group presented with a highest prevalence of neuro-vascular invasion, capsular invasion and lymph node metastasis. Together with individuals of advanced age, that group also had larger tumor diameter and higher prevalence of extra-glandular disease. Even when analyzed only cases with well-differentiated carcinoma, younger individuals remain with a highest prevalence of lymph node metastasis, neuro-vascular invasion and larger tumor diameter.

Conclusion We observed a distinct pattern of clinicopathological manifestation of thyroid cancer according to age. Individuals belonging to age extremes resemble in several pathological features, and young people usually present with more aggressive disease characteristics.

AGK-BRAF gene fusion is a recurrent event in sporadic pediatric thyroid carcinoma

Thyroid cancer is the fastest increasing cancer worldwide in all age groups. Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer in both adults and children. PTC genomic landscape has been extensively studied in adults, but information regarding sporadic pediatric patients is lacking. Although BRAF V600E mutation is highly prevalent in adults, this mutation is uncommon in pediatric cases. As adult and pediatric PTC is a mitogen‐activated protein kinase‐driven cancer, this altered pathway might be activated by different genetic events. The aim of this study was to investigate the occurrence of AGK‐BRAF fusion gene, recently described in radiation‐exposed pediatric PTC, in a cohort of exclusively sporadic pediatric PTC. The series consisted of 30 pediatric PTC younger than 18 years of age at the time of diagnosis and 15 matched lymph node metastases (LNM). Primary tumors and matched LNM were screened for the presence of the AGK‐BRAF fusion transcript by RT‐PCR. To confirm the identity of the amplified products, randomly selected samples positive for the presence of the fusion transcripts were sequenced. Moreover, BRAF dual‐color, break‐apart probes confirmed BRAF rearrangement. Overall, the AGK‐BRAF fusion gene was detected in 10% (3/30) of primary tumors. For one of these cases, paired LNM was also available, which also shows the presence of AGK‐BRAF fusion gene. This study described, for the first time, the presence of AGK‐BRAF in sporadic pediatric PTC. Understanding the molecular events underlying pediatric PTC may improve preoperative diagnosis, allow molecular prognostication and define a therapeutic approach toward sporadic PTC patients.

Mutational Analysis in Pediatric Thyroid Cancer and Correlations with Age, Ethnicity, and Clinical Presentation

BACKGROUND

Well-differentiated thyroid cancer (WDTC) incidence in pediatrics is rising, most being papillary thyroid carcinoma (PTC). The objective of the study was to assess the prevalence of different mutations in pediatric WDTC and correlate the genotype with the clinical phenotype.

METHODS

This is a single-center retrospective study. Thyroid tissue blocks from 42 consecutive pediatric WDTC patients who underwent thyroidectomy between 2001 and 2013 were analyzed at Quest Diagnostics for BRAF(V600E), RAS mutations (N,K,H), and RET/PTC and PAX8/PPARγ rearrangements, using validated molecular methods. Thyroid carcinomas included PTC, follicular thyroid carcinoma (FTC), and follicular variant of PTC (FVPTC).

RESULTS

Thirty-nine samples (29 females) were genotyped. The mean age at diagnosis was 14.7 years (range 7.9-18.4 years), and most were Hispanic (56.4%) or Caucasian (35.9%). The mean follow-up period was 2.9 years. Mutations were noted in 21/39 (53.8%), with both BRAF(V600E) (n = 9), and RET/PTC (n = 6) detected only in PTC. Mutations were detected in 2/5 FTC (PAX8/PPARγ and NRAS) and 3/6 FVPTC cases (PAX8/PPARγ). Of 28 PTC patients, 57.1% had mutations: 32.1% with BRAF(V600E), 21.4% with RET/PTC, and 3.6% with NRAS. Of patients with BRAF(V600E), 77.8% were Hispanic and 88.9% were >15 years, while all RET/PTC-positive patients were ≤15 years (p = 0.003). Tumor size, lymph node involvement, and distant metastasis at diagnosis (or soon after (131)I ablation) did not vary significantly based on the mutation.

CONCLUSIONS

BRAF(V600E) was the most common mutation, especially in older and Hispanic adolescents. A larger, ethnically diverse pediatric cohort followed long term will enable the genotypic variability, clinical presentation, and response to therapy to be better assessed.

Gene signature of the post-Chernobyl papillary thyroid cancer

Purpose

Following the nuclear accidents in Chernobyl and later in Fukushima, the nuclear community has been faced with important issues concerning how to search for and diagnose biological consequences of low-dose internal radiation contamination. Although after the Chernobyl accident an increase in childhood papillary thyroid cancer (PTC) was observed, it is still not clear whether the molecular biology of PTCs associated with low-dose radiation exposure differs from that of sporadic PTC.

Methods

We investigated tissue samples from 65 children/young adults with PTC using DNA microarray (Affymetrix, Human Genome U133 2.0 Plus) with the aim of identifying molecular differences between radiation-induced (exposed to Chernobyl radiation, ECR) and sporadic PTC. All participants were resident in the same region so that confounding factors related to genetics or environment were minimized.

Results

There were small but significant differences in the gene expression profiles between ECR and non-ECR PTC (global test, p < 0.01), with 300 differently expressed probe sets (p < 0.001) corresponding to 239 genes. Multifactorial analysis of variance showed that besides radiation exposure history, the BRAF mutation exhibited independent effects on the PTC expression profile; the histological subset and patient age at diagnosis had negligible effects. Ten genes (PPME1, HDAC11, SOCS7, CIC, THRA, ERBB2, PPP1R9A, HDGF, RAD51AP1, and CDK1) from the 19 investigated with quantitative RT-PCR were confirmed as being associated with radiation exposure in an independent, validation set of samples.

Conclusion

Significant, but subtle, differences in gene expression in the post-Chernobyl PTC are associated with previous low-dose radiation exposure.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-015-3303-3) contains supplementary material, which is available to authorized users.

Identification of epistatic interactions through genome-wide association studies in sporadic medullary and juvenile papillary thyroid carcinomas

Background

The molecular mechanisms leading to sporadic medullary thyroid carcinoma (sMTC) and juvenile papillary thyroid carcinoma (PTC), two rare tumours of the thyroid gland, remain poorly understood. Genetic studies on thyroid carcinomas have been conducted, although just a few loci have been systematically associated. Given the difficulties to obtain single-loci associations, this work expands its scope to the study of epistatic interactions that could help to understand the genetic architecture of complex diseases and explain new heritable components of genetic risk.

Methods

We carried out the first screening for epistasis by Multifactor-Dimensionality Reduction (MDR) in genome-wide association study (GWAS) on sMTC and juvenile PTC, to identify the potential simultaneous involvement of pairs of variants in the disease.

Results

We have identified two significant epistatic gene interactions in sMTC (CHFR-AC016582.2 and C8orf37-RNU1-55P) and three in juvenile PTC (RP11-648k4.2-DIO1, RP11-648k4.2-DMGDH and RP11-648k4.2-LOXL1). Interestingly, each interacting gene pair included a non-coding RNA, providing thus support to the relevance that these elements are increasingly gaining to explain carcinoma development and progression.

Conclusions

Overall, this study contributes to the understanding of the genetic basis of thyroid carcinoma susceptibility in two different case scenarios such as sMTC and juvenile PTC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-015-0160-7) contains supplementary material, which is available to authorized users.

Are we really at the dawn of understanding sporadic pediatric thyroid carcinoma?

Data from the National Cancer Institute and from the literature have disclosed an increasing incidence of thyroid cancer in children, adolescents and adults. Although children and adolescents with thyroid cancer tend to present with more advanced disease than adults, their overall survival rate is excellent; however, there is no clear explanation for the differences observed in the clinicopathological outcomes in these age groups. There has been an ongoing debate regarding whether the clinicopathological differences may be due to the existence of distinct genetic alterations. Efforts have been made to identify these acquired genetic abnormalities that will determine the tumor's biological behavior and ultimately allow molecular prognostication. However, most of the studies have been performed in radiation-exposed pediatric thyroid carcinoma. Therefore, our understanding of the role of these driver mutations in sporadic pediatric differentiated thyroid cancer development is far from complete, and additionally, there is a strong need for studies in both children and adolescents. The aim of this review is to present an extensive literature review with emphasis on the molecular differences between pediatric sporadic and radiation-exposed differentiated thyroid carcinomas and adult population.