A six-genotype genetic prognostic model for papillary thyroid cancer

Genetic trio of BRAF and TERT alterations and rs2853669TT in papillary thyroid cancer aggressiveness

BACKGROUND

BRAF V600E and TERT promoter alterations are core components in current genetics-based risk assessment for precision management of papillary thyroid cancer. It remains unknown whether this approach could achieve even better precision through a widely recognized prognostic single-nucleotide variation (SNV, formerly SNP), rs2853669T>C, in the TERT promoter.

METHODS

The genetic status of alterations and SNV were examined by sequencing genomic DNA from papillary thyroid cancer in 608 patients (427 women and 181 men) aged 47 years (interquartile range = 37-57), with a median follow-up time of 75 months (interquartile range = 36-123), and their relationship with clinical outcomes was analyzed. A luciferase reporter assay was performed to examine TERT promoter activities.

RESULTS

TERT promoter alterations showed a strong association with papillary thyroid cancer recurrence in the presence of genotype TT of rs2853669 (adjusted hazard ratio [HR] = 2.12, 95% confidence interval [CI] = 1.10 to 4.12) but not TC/CC (adjusted HR = 1.17, 95% CI = 0.56 to 2.41). TERT and BRAF alterations commonly coexisted and synergistically promoted papillary thyroid cancer recurrence. With this genetic duet, TT of rs2853669 showed a robustly higher disease recurrence than TC/CC (adjusted HR = 14.26, 95% CI = 2.86 to 71.25). Patients with the genetic trio of BRAF V600E, TERT alteration, and TT of rs2853669 had a recurrence of 76.5% vs recurrence of 8.4% with neither variation and with TC/CC (HR = 13.48, 95% CI = 6.44 to 28.21). T allele of rs2853669 strongly increased TERT promoter activities, particularly the variant promoters.

CONCLUSIONS

The SNV rs2853669T>C dramatically refines the prognostic power of BRAF V600E and TERT promoter alterations to a higher precision, suggesting the need for including this SNV in the current genetics-based risk prognostication of papillary thyroid cancer.

BRAFV600E mutation does not predict lymph node metastases and recurrence in Chinese papillary thyroid microcarcinoma patients

OBJECT

Previous studies suggest BRAFV600E mutation is a marker for poor prognosis in papillary thyroid cancer, however, its ability to further risk stratify papillary thyroid microcarcinoma (PTMC) remains controversial. We aimed to explore the association between BRAFV600E mutation and the clinicopathological features and recurrence in Chinese PTMC patients.

METHODS

We retrospectively reviewed 2094 PTMC patients who underwent surgery and had a valid BRAFV600E mutation test result. Among them, 1292 patients had complete follow-up data. The mutation incidence was determined. Moreover, the clinicopathological characteristics, disease-free survival (DFS), and response to therapy distribution were compared between the mutation and non-mutation groups.

RESULTS

BRAFV600E mutation was observed in 90.6 % of all patients and 89.2 % of patients with complete follow-up data. No significant difference was observed in lymph node metastases (LNM) number categories between the mutation and non-mutation groups among all patients (P = 0.329) and 1292 patients (P = 0.408). Neither the 3-year DFS (97.9 % vs. 98.0 %, P = 0.832) nor the response to therapy distribution (P > 0.05) indicated a significant difference between the mutation and non-mutation groups. The 3-year DFS differs among patients having different LNM number categories (99.8 % vs. 98.5 % vs. 77.3 %, P < 0.001). Multivariate analysis revealed that high-volume (over 5) LNM (Total thyroidectomy (TT): OR = 4.000, 95 % CI 2.390-6.694, P < 0.001; Unilateral thyroidectomy (UT): OR = 4.183, 95 % CI 1.565-11.190, P = 0.004), rather than BRAFV600E mutation (P > 0.05), was an independent risk factor of response to therapy.

CONCLUSIONS

Our results suggested that BRAFV600E mutation could not accurately predict LNM or the recurrence of Chinese PTMC patients. Moreover, high-volume LNM is significantly associated with PTMC prognosis.

Risk stratification by combining common genetic mutations and TERT promoter methylation in papillary thyroid cancer

PURPOSE

Risk stratification based on somatic mutations in TERT promoter and BRAF/RAS has been well established for papillary thyroid cancer (PTC), and there is emerging evidence showed that TERT promoter methylation was frequently observed in thyroid cancer patients with adverse features. This study was aimed to comprehensive explore the prognostic value of BRAF/RAS mutations, TERT promoter mutations, and TERT promoter methylation in PTC.

METHODS

The relationships of BRAF/RAS mutations, TERT promoter mutations, and TERT promoter methylation with clinical characteristics and outcomes of PTC were analyzed in 382 patients with PTC.

RESULTS

TERT promoter mutation and hypermethylation were collectively observed in 52 (13.6%) samples and associated with BRAF/RAS mutation, aggressive clinical characteristics, and poor clinical outcomes of PTC. Coexistence of BRAF/RAS and TERT alterations was found in 45 of 382 (11.8%) PTC patients and strongly associated with old patient age, extrathyroidal extension, advanced pathologic T stage and metastasis. Importantly, patients with both BRAF/RAS and TERT alterations had higher rates of tumor recurrence (13.6% vs 1.5%, P = 0.042) and disease progression (24.4% vs 3.3%, P < 0.001) than patients without any alterations, and cox regression analysis revealed that the coexistence of BRAF/RAS and TERT alterations, but not BRAF/RAS or TERT alterations alone, increased the risk of progression-free interval with an adjusted HR of 10.35 (95% CI: 1.79-59.81, P = 0.009).

CONCLUSIONS

This study suggested that comprehensively analysis of BRAF/RAS mutations, TERT promoter mutation and methylation is an effective strategy to identify high-risk patients with PTC.

Excellent Response to Therapy Occurs for Most Patients With Thyroid Cancer Treated With Lobectomy

INTRODUCTION

American Thyroid Association (ATA) Guidelines for Management of Thyroid Nodules and Thyroid Cancer indicate that thyroid lobectomy (TL) or total thyroidectomy (TT) are appropriate surgery for low- and intermediate-risk well-differentiated thyroid carcinoma. We sought to determine outcomes of TL or TT by ATA response to therapy (RTT) classification.

METHODS

This is a single-institution retrospective cohort study of adults with unilateral suspicious or malignant thyroid nodules under 4 cm from January 2016 through December 2021. Our primary outcome was ATA RTT.

RESULTS

During the study period, 118 met inclusion criteria: 37 (31%) underwent TL and 81 (69%) TT. Of the TL patients, 7 (19%) underwent completion thyroidectomy. Response to therapy (RTT) was similar with TT versus TL: excellent response 56 (69%) versus 30 (81%), indeterminate response 20 (25%) versus 5 (14%), and biochemically incomplete response 5 (6%) versus 2 (5%), P = 0.20. There were no differences between the groups for age, sex, race or ethnicity, tumor size, histologic type, or complications. Thyroidectomy (TT) was associated with multiple nodules 47% versus 22% for TL (P = 0.009), bilateral nodules 43% versus 16% (P = 0.004), central neck lymph nodes removed median 3 (interquartile range [IQR] 1-8) versus 0 (IQR 0-2) P < 0.001, lymph node metastases median 0 (IQR 0-1) versus 0 (0-0) P = 0.02. Median follow-up was 32.5 mo (IQR 17-56 mo) and was similar between the groups.

CONCLUSIONS

Patients with TL for well-differentiated thyroid carcinoma without high-risk features have an RTT similar to patients undergoing TT. In this cohort, 81% of patients treated with TL have not required additional intervention.

The prognostic power of gene mutations in thyroid cancer

The introduction and generalization of next-generation sequencing techniques have significantly increased the identification of mutations in thyroid tumors from multiple patient cohorts. The understanding of the association between specific mutations and clinical outcomes is gradually leading to individualizing the care of patients with thyroid cancer. BRAFV600 is the most common mutation seen in thyroid cancer patients and unequivocally predicts malignancy, but when considered in isolation, it is not recommended to be used as an independent prognostic factor. Mutations in RAS are the second most common alterations in thyroid cancer but can be found in benign and malignant lesions. Rearrangements involving receptor tyrosine kinases, primarily RET, are found in a subset of thyroid tumors without mutations in either BRAF or RAS. The assessment of additional mutations is increasingly employed in thyroid cancer prognostication. The coexistence of BRAF with alterations in genes such as PIK3CA, TERT promoter, or TP53 is associated with less favorable outcomes. Similar studies have also shown that additional oncogenic mutations in RAS-mutant thyroid carcinoma, such as those affecting the EIF1AX gene, likely predict a more aggressive clinicopathologic behavior. Overall, emerging evidence suggests that the co-occurrence of specific alterations in defined genes with BRAF or RAS mutations can become prognostic tools and useful predictors of thyroid tumor aggressiveness.

Pediatric thyroid cancer: Recent developments

Thyroid cancer is rare in children but its incidence is increasing. Recent data have clarified important similarities and differences between thyroid cancers originating in childhood and in adulthood. The genetic drivers of pediatric thyroid cancers are similar to those in adult tumors but comprise more gene fusions and fewer point mutations. Clinically, despite frequent metastatic spread, pediatric thyroid cancer has an excellent prognosis and mortality is rare. Therefore, treatment approaches must weigh carefully the morbidity of thyroid cancer treatments against their benefits. Current key questions include which children require total thyroidectomy rather than more limited-and safer-lobectomy, and in which children does the benefit of radioactive iodine therapy outweigh its risk of inducing a secondary malignancy. Finally, molecular therapies targeting genetic drivers of thyroid cancer now provide effective treatment for children with progressive, radioiodine-refractory disease, as well as opportunities to explore novel neoadjuvant uses that facilitate therapeutic surgery or radioactive iodine.

Development of a Risk Predictive Model for Evaluating Immune Infiltration Status in Invasive Thyroid Carcinoma

Aims

This study aimed to reveal the molecular characteristics and potential biomarker of immune-activated and immunosuppressive invasive thyroid carcinoma.

Methods

Expression and clinical data for invasive thyroid carcinoma were obtained from the TCGA database. Tumor samples were divided into immune-activated or immunosuppressive groups based on the immune enrichment score calculated by ssGSEA. Differentially expressed genes (DEGs) between tumor vs. normal groups or between immune-activated vs. immunosuppressive groups were screened, followed by functional enrichment. Immune infiltration was evaluated using the ESTIMATE, CIBERSORTx, and EPIC algorithms, respectively. A random forest algorithm and Lasso cox analysis were used to identify gene signatures for risk model construction.

Results

Totally 1171 DEGs were screened between tumor vs. normal groups, and multiple tumorigenesis-associated pathways were significantly activated in invasive thyroid carcinoma. Compared to immune-activated samples, immunosuppressive samples showed higher tumor purity, lower immune/stromal scores, and lower expression of immune markers, as well as lower infiltration abundance of CD4+ T cells and CD8+ T cells. A risk model based on a 12-immune signature (CCR7, CD1B, CD86, CSF2RB, HCK, HLA-DQA1, LTA, LTB, LYZ, NOD2, TNFRSF9, and TNFSF11) was developed to evaluate the immune infiltration status (AUC = 0.998; AUC of 0.958 and 0.979 in the two external validation datasets), which showed a higher clinical benefit and high accuracy. Immune-activated samples presented lower IC50 value for bortezomib, MG.132, staurosporine, and AZD8055, indicating sensitivity to these drugs.

Conclusion

A 12-gene-based immune signature was developed to predict the immune infiltration status for invasive thyroid carcinoma patients and then to identify the subsets of invasive thyroid carcinoma patients who might benefit from immunotherapy.

Papillary Thyroid Cancer Prognosis: An Evolving Field

Simple Summary

Over the last couple of decades, the prognostic stratification systems of differentiated thyroid cancer (DTC) patients have been revised several times in an attempt to achieve a tailored clinical management reflecting the single patients’ needs. Such revisions are likely to continue in the near future, since the prognostic value of a number of promising clinicopathological features and new molecular biomarkers are being evaluated. Here, we will review the current staging systems of thyroid cancer patients and discuss the most relevant clinicopathological parameters and new molecular markers that are potentially capable of refining the prognosis.

Abstract

Over the last few years, a great advance has been made in the comprehension of the molecular pathogenesis underlying thyroid cancer progression, particularly for the papillary thyroid cancer (PTC), which represents the most common thyroid malignancy. Putative cancer driver mutations have been identified in more than 98% of PTC, and a new PTC classification into molecular subtypes has been proposed in order to resolve clinical uncertainties still present in the clinical management of patients. Additionally, the prognostic stratification systems have been profoundly modified over the last decade, with a view to refine patients’ staging and being able to choose a clinical approach tailored on single patient’s needs. Here, we will briefly discuss the recent changes in the clinical management of thyroid nodules, and review the current staging systems of thyroid cancer patients by analyzing promising clinicopathological features (i.e., gender, thyroid auto-immunity, multifocality, PTC histological variants, and vascular invasion) as well as new molecular markers (i.e., BRAF/TERT promoter mutations, miRNAs, and components of the plasminogen activating system) potentially capable of ameliorating the prognosis of PTC patients.

Significance of DMBT1 in Papillary Thyroid Carcinoma Concurrent With Hashimoto's Thyroiditis

Background

Papillary thyroid carcinoma (PTC) concurrent with Hashimoto’s thyroiditis (HT) was associated with a better clinical prognosis. This study aimed to investigate a potential mRNA gene that affects the development of PTC, which helps PTC concurrent with HT patients have a better prognosis.

Material/Methods

PTC data were obtained from The Cancer Genome Atlas (TCGA) database. And the validation data of tissue specimens were collected from Guangzhou First People’s Hospital. The thyroid tissue sections were hybridized with deleted in malignant brain tumor 1 (DMBT1) probes by situ hybridization. Survival rates were analyzed using Kaplan-Meier curves, and the log-rank test was used to compare group survival rates. Prognosis clinicopathological factors were analyzed by Cox regression. Gene Ontology (GO) and Kyoto Gene and Genomic Encyclopedia (KEGG) pathway enrichment analyses were performed using single-sample gene set enrichment analysis (ssGSEA). Finally, the correlation of deletion in DMBT1 expression with overall immune status, tumor purity, and human leukocyte antigen (HLA) gene expression profile was analyzed.

Results

HT was significantly associated with sex, tumor foci, extrathyroidal extension (ETE), residual tumor, and tumor stage (T stage). Moreover, PTC concurrent with HT had a lower risk of recurrence versus non-HT groups. A total of 136 differentially expressed mRNAs (DEMs) were identified between HT and non-HT groups. Among them, the expression level of DMBT1 in HT groups was statistically higher than that in non-HT groups. A significant association with ETE and recurrence was revealed in the high expression and the low expression of DMBT1. Furthermore, DMBT1 was an independent predictor of survival. The overall immune activity of high expression of DMBT1 was higher than that of the low-expression group.

Conclusions

The PTC patients with HT had better behavior features and prognosis than those with simple PTC. DMBT1 in PTC-HT patients was a potential possible factor that inhibits tumors. High expression of DMBT1 may improve PTC prognosis by immune-related pathways.

Significance of RAS Mutations in Thyroid Benign Nodules and Non-Medullary Thyroid Cancer

Simple Summary

Only about 4% of thyroid nodules are carcinomas and require surgery. Fine-needle aspiration cytology is the most accurate tool to distinguish benign from malignant thyroid nodules, however it yields an indeterminate result in about 30% of the cases, posing diagnostic and prognostic dilemmas. Testing for genetic mutations, including those of RAS, has been proposed for indeterminate cytology to solve these dilemmas and support the clinician decision making process. A passionate debate is ongoing on the biological and clinical significance of RAS mutations, calling into question the utility of RAS as tumor marker. Recently, the description of a new entity of non-invasive follicular thyroid neoplasm and the accurate review of more recent analyses demonstrate that RAS mutations have limited utility in both the diagnostic and prognostic setting of thyroid nodular disease.

Abstract

Thyroid nodules are detected in up to 60% of people by ultrasound examination. Most of them are benign nodules requiring only follow up, while about 4% are carcinomas and require surgery. Malignant nodules can be diagnosed by the fine-needle aspiration cytology (FNAC), which however yields an indeterminate result in about 30% of the cases. Testing for RAS mutations has been proposed to refine indeterminate cytology. However, the new entity of non-invasive follicular thyroid neoplasm, considered as having a benign evolution and frequently carrying RAS mutations, is expected to lower the specificity of this mutation. The aggressive behavior of thyroid cancer with RAS mutations, initially reported, has been overturned by the recent finding of the cooperative role of TERT mutations. Although some animal models support the carcinogenic role of RAS mutations in the thyroid, evidence that adenomas harboring these mutations evolve in carcinomas is lacking. Their poor specificity and sensitivity make the clinical impact of RAS mutations on the management of thyroid nodules with indeterminate cytology unsatisfactory. Evidence suggests that RAS mutation-positive benign nodules demand a conservative treatment. To have a clinical impact, RAS mutations in thyroid malignancies need not to be considered alone but rather together with other genetic abnormalities in a more general context.

The ETS Inhibitor YK-4-279 Suppresses Thyroid Cancer Progression Independent of TERT Promoter Mutations

Hotspot mutations in the core promoter region of the telomerase reverse transcriptase (TERT) gene have been well established to associate with aggressive clinical characteristics, radioiodine refractory, tumor recurrence, and mortality in thyroid cancer. Several E-twenty-six (ETS) transcription factors were reported to selectively bound to the mutant TERT promoter and activated TERT expression. In this study we aimed to investigate whether TERT promoter mutations confer sensitivity to ETS inhibitor YK-4-279 in thyroid cancer cells and whether this inhibitor could be served as a potential therapeutic agent for thyroid cancer. In vitro assays showed that YK-4-279 treatment sharply suppressed cell viability, colony formation, migration, and invasion, as well as induced cell cycle arrest and apoptosis in a panel of thyroid cancer cells. The cell viability after YK-4-279 treatment was similar between cell lines harboring mutant and wild-type TERT promoters. Furthermore, YK-4-279 treatment reduced both luciferase activity and mRNA expression of TERT independent of TERT promoter mutation status. Data from RNA-seq further revealed that YK-4-279 significantly affected biological processes including DNA replication and cell cycle. Reduced DNA helicase activity and decreased expression of several helicase genes were observed after YK-4-279 treatment. Moreover, YK-4-279 significantly inhibited tumor growth and induced apoptosis in a xenograft mice model. Thus, ETS inhibitor YK-4-279 suppressed TERT expression and conferred anti-tumor activity in a TERT promoter mutation-independent manner, and it could be a potential agent for the treatment of advanced thyroid cancers.

Genetic Determinants for Prediction of Outcome of Patients with Papillary Thyroid Carcinoma

Papillary thyroid carcinoma (PTC) usually presents an excellent prognosis, but some patients present with aggressive metastatic disease. BRAF, RAS, and TERT promoter (TERTp) genes are altered in PTC, and their impact on patient outcomes remains controversial. We aimed to determine the role of genetic alterations in PTC patient outcomes (recurrent/persistent disease, structural disease, and disease-specific mortality (DSM)). The series included 241 PTC patients submitted to surgery, between 2002-2015, in a single hospital. DNA was extracted from tissue samples of 287 lesions (primary tumors and metastases). Molecular alterations were detected by Sanger sequencing. Primary tumors presented 143 BRAF, 16 TERTp, and 13 RAS mutations. Isolated TERTpmut showed increased risk of structural disease (HR = 7.0, p < 0.001) and DSM (HR = 10.1, p = 0.001). Combined genotypes, BRAFwt/TERTpmut (HR = 6.8, p = 0.003), BRAFmut/TERTpmut (HR = 3.2, p = 0.056) and BRAFmut/TERTpwt (HR = 2.2, p = 0.023) showed increased risk of recurrent/persistent disease. Patients with tumors BRAFwt/TERTpmut (HR = 24.2, p < 0.001) and BRAFmut/TERTpmut (HR = 11.5, p = 0.002) showed increased risk of structural disease. DSM was significantly increased in patients with TERTpmut regardless of BRAF status (BRAFmut/TERTpmut, log-rank p < 0.001; BRAFwt/TERTpmut, log-rank p < 0.001). Our results indicate that molecular markers may have a role in predicting PTC patients' outcome. BRAFmut/TERTpwt tumors were prone to associate with local aggressiveness (recurrent/persistent disease), whereas TERTpmut tumors were predisposed to recurrent structural disease and DSM.

Thyroid cancer and its associated factors: A population-based case-control study

Considering the rising incidence and mortality of thyroid cancer (TC) worldwide, the aim of our study was to determine the risk factors for TC in a province with the highest incidence of TC in the country located at the South of Iran. A population-based case-control study was performed on 708 participants (361 new cases and 347 controls). The case participants were selected from the Iranian National Cancer Registry database. Frequency matched for gender and age, and the control participants were selected randomly from the neighborhood of the cases. Based on the results of multiple logistic regression analysis, benign thyroid diseases (eg, hyperthyroidism OR_yes/no = 14.06, 95% CI: 5.13-38.51), family history of TC (OR_yes/no = 3.54, 95% CI: 1.51-8.26), radiation exposure of the head (OR_yes/no = 1.92, 95% CI: 1.03-3.60), family history of thyroid diseases (OR_yes/no = 1.76, 95% CI: 1.19-2.62) and family history of other types of cancer (OR_yes/no = 1.67, 95% CI: 1.01-2.74), significantly increased the risk of developing TC. On the other hand, high blood pressure (OR_yes/no = 0.35, 95% CI: 0.19-0.64), higher education (OR_{college/illiterate} = 0.54, 95% CI: 0.30-0.96), consumption of unsaturated fat (OR_{unsaturated/saturated} = 0.59, 95% CI: 0.39-0.87) and being married (OR_{married/single} = 0.60, 95% CI 0.37-0.98) were found to be protective factors. Some community-based interventions, for example, reduction in radiation exposure and screening members of families with underlying thyroid diseases may help in preventing or early diagnosis of TC. More studies on the health effects of local herbs are highly recommended.

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.

Risk assessment for distant metastasis in differentiated thyroid cancer using molecular profiling: A matched case-control study

Background

Risk stratification for patients with differentiated thyroid cancer (DTC) is based primarily on pathologic tumor characteristics. Accurate preoperative prognostication could allow for more informed initial surgical recommendations, particularly among patients at a higher risk for distant metastasis (DM). The objective of this study was to characterize the genetic profile of DTC with DM and to validate a molecular‐based risk stratification.

Methods

A case‐control study design was used to analyze patients who had DTC with DM (n = 62) and a propensity matched cohort of patients who had DTC without DM after at least 5 years of follow‐up using the ThyroSeq version 3 targeted next‐generation sequencing assay. The results were classified into high‐risk, intermediate‐risk, and low‐risk of aggressive disease.

Results

Most patients who had DTC with DM (66%) had a late‐hit mutation in TERT, TP53, or PIK3CA. After propensity matching by age, tumor size, and sex, the high‐risk molecular profile had strong association with DM (high‐risk vs intermediate‐risk: odds ratio, 25.1; 95% CI, 3.07‐204.4; P < .001; high‐risk vs low‐risk: odds ratio, 122.5; 95% CI, 14.5‐1038.4; P < .001). Overall, molecular risk categories were associated with DM risk, with a concordance index of 0.836 (95% CI, 0.759‐0.913), which remained consistent after internal validation. Within the range of 5% to 10% of DM observed in DTC, the expected probability of DM would be 0.2% to 0.4% for the low‐risk molecular profile, 4.7% to 9.4% for the intermediate‐risk molecular profile, and 19.3% to 33.5% for the high‐risk molecular profile.

Conclusions

In this matched case‐control study, genetic profiling using an available molecular assay provided accurate and robust risk stratification for DM in patients with DTC. The availability of preoperative prognostication may allow tailoring treatment for patients with DTC.

In this matched case‐control study, comprehensive genetic profiling provides accurate and robust risk stratification for distant metastasis in patients with differentiated thyroid cancer. The availability of preoperative prognostication may allow for molecular‐directed treatment recommendations to tailor care for these patients.

The Coexistence of Genetic Mutations in Thyroid Carcinoma Predicts Histopathological Factors Associated With a Poor Prognosis: A Systematic Review and Network Meta-Analysis

PURPOSE

Genetic mutations may play an important role in the progression and invasion of thyroid carcinoma (TC), and their coexistence may result in mutational synergy. The presence of the BRAFV600E mutation, as well as mutations affecting the TERT promoter, RAS, CHEK2 and RET/PTC, may all have an impact on prognosis. The aim of this study was to explore whether synergy between the coexistent mutations predicts histopathological prognostic factors that influence disease outcome.

METHODS

A comprehensive literature search of PubMed, Embase and the Cochrane Library, from their inception until January 2020. Primary outcomes included: disease stage, lymph node metastasis, extrathyroidal extension and distant metastasis; while, secondary outcomes included: tumor recurrence, mortality, invasion of thyroid capsule, multiplicity, presented as an odds ratio (OR) with 95% credible intervals (CrI).

RESULTS

27 publications (comprising 9 active intervention arms), involving 8,388 TC patients, were selected. Network meta-analytic estimates of active interventions contrasted with other active interventions, with random effects, were calculated. In terms of outcomes focus on overall TC, BRAFV600E + TERT co-mutation ranked highest for diseases stage (OR = 5.74, 95% CrI: 3.09-10.66), as well as lymph node metastasis, extrathyroidal extension (5.74, 4.06-8.10), tumor recurrence (7.21, 3.59-14.47), and invasion of the thyroid capsule (3.11, 1.95-4.95). BRAFV600E + TERT co-mutation ranked secondary in distant metastasis, mortality, and multiplicity that ranked highest was TERT+RAS or RAS. When we were limited to the study of patients with papillary TC (PTC), BRAFV600E + TERT always ranked highest for primary outcomes: disease stage (6.39, 3.13-13.04), lymph node metastasis, extrathyroidal extension (5.80,3.89-8.64) and distant metastasis (7.33, 3.00-17.89), while BRAFV600E + TERT again ranked highest in secondary outcomes: tumor recurrence (7.23,3.37-15.51), mortality (9.26, 3.02-28.42), invasion of thyroid capsule (3.20,2.01-5.11), and multiplicity.

CONCLUSIONS

In this molecular marker mutation-based systematic review and network meta-analysis, we found that coexistent BRAFV600E + TERT genetic co-mutations predicted poor histopathological prognosis, including progression, invasion, and metastasis, especially in PTC. For the overall TC, the BRAFV600E + TERT + RAS triple mutations may have a greater impact on the prognosis, and further research should related to potentially important features. This study is registered with PROSPERO, number CRD42019143242.

Hemithyroidectomy for Thyroid Cancer: A Review

Thyroid cancer incidence is on the rise; however, fortunately, the death rate is stable. Most persons with well-differentiated thyroid cancer have a low risk of recurrence at the time of diagnosis and can expect a normal life expectancy. Over the last two decades, guidelines have recommended less aggressive therapy for low-risk cancer and a more personalized approach to treatment of thyroid cancer overall. The American Thyroid Association (ATA) and National Comprehensive Cancer Network (NCCN) thyroid cancer guidelines recommend hemithyroidectomy as an acceptable surgical treatment option for low-risk thyroid cancer. Given this change in treatment paradigms, an increasing number of people are undergoing hemithyroidectomy rather than total or near-total thyroidectomy as their primary surgical treatment of thyroid cancer. The postoperative follow-up of hemithyroidectomy patients differs from those who have undergone total or near-total thyroidectomy, and the long-term monitoring with imaging and biomarkers can also be different. This article reviews indications for hemithyroidectomy, as well as postoperative considerations and management recommendations for those who have undergone hemithyroidectomy.

Telomerase reverse transcriptase promoter mutations in thyroid carcinomas: implications in precision oncology-a narrative review

Telomerase is a ribonucleoprotein enzyme with telomerase reverse transcriptase (TERT) as a catalytic component. In normal human follicular thyroid cells or thyrocytes, telomerase is silent due to the TERT gene being tightly repressed. However, during the formation of thyroid carcinoma (TC), telomerase becomes activated via TERT induction. The TERT promoter’s gain-of-function mutation has recently been identified in TCs and many other malignancies. The mutation creates a de novo ETS-binding motif through which TERT transcription is de-repressed and telomerase is activated; through this, the mutant TERT promoter promotes the development of TC, contributes to disease aggressiveness and treatment resistance, and thereby leads to poor patient outcomes. From a clinical point of view, the strong association between the TERT promoter mutation and disease malignancy and aggressiveness holds great promise for its value in TC diagnostics, risk stratification, prognostication, treatment decision, and follow-up design. In the present review article, we summarize the recent findings of studies of TERT promoter mutations in TC and underscore the implications of TERT hyperactivity driven by genetic events in the pathogenesis and management of TC. Finally, the targeting of TERT promoter mutations and the disruption of telomere maintenance are considered as potential therapeutic strategies against TC.

Potential five-mRNA signature model for the prediction of prognosis in patients with papillary thyroid carcinoma

Although the mortality rate of papillary thyroid carcinoma (PTC) is relatively low, the recurrence rates of PTC remain high. The high recurrence rates are related to the difficulties in treatment. Gene expression profiles has provided novel insights into potential therapeutic targets and molecular biomarkers of PTC. The aim of the present study was to identify mRNA signatures which may categorize PTCs into high-and low-risk subgroups and aid with the predictions for prognoses. The mRNA expression profiles of PTC and normal thyroid tissue samples were obtained from The Cancer Genome Atlas (TCGA) database. Differentially expressed mRNAs were identified using the ‘EdgeR’ software package. Gene signatures associated with the overall survival of PTC were selected, and enrichment analysis was performed to explore the biological pathways and functions of the prognostic mRNAs using the Database for Visualization, Annotation and Integration Discovery. A signature model was established to investigate a specific and robust risk stratification for PTC. A total of 1,085 differentially expressed mRNAs were identified between the PTC and normal thyroid tissue samples. Among them, 361 mRNAs were associated with overall survival (P<0.05). A 5-mRNA prognostic signature for PTC (ADRA1B, RIPPLY3, PCOLCE, TEKT1 and SALL3) was identified to classify the patients into high-and low-risk subgroups. These prognostic mRNAs were enriched in Gene Ontology terms such as ‘calcium ion binding’, ‘enzyme inhibitor activity’, ‘carbohydrate binding’, ‘transcriptional activator activity’, ‘RNA polymerase II core promoter proximal region sequence-specific binding’ and ‘glutathione transferase activity’, and Kyoto Encyclopedia of Genes and Genomes signaling pathways such as ‘pertussis’, ‘ascorbate and aldarate metabolism’, ‘systemic lupus erythematosus’, ‘drug metabolism-cytochrome P450 and ‘complement and coagulation cascades’. The 5-mRNA signature model may be useful during consultations with patients with PTC to improve the prediction of their prognosis. In addition, the prognostic signature identified in the present study may reveal novel therapeutic targets for patients with PTC.

Current and Future Role of Tyrosine Kinases Inhibition in Thyroid Cancer: From Biology to Therapy

Thyroid cancer represents a heterogenous disease whose incidence has increased in the last decades. Although three main different subtypes have been described, molecular characterization is progressively being included in the diagnostic and therapeutic algorithm of these patients. In fact, thyroid cancer is a landmark in the oncological approach to solid tumors as it harbors key genetic alterations driving tumor progression that have been demonstrated to be potential actionable targets. Within this promising and rapid changing scenario, current efforts are directed to improve tumor characterization for an accurate guidance in the therapeutic management. In this sense, it is strongly recommended to perform tissue genotyping to patients that are going to be considered for systemic therapy in order to select the adequate treatment, according to recent clinical trials data. Overall, the aim of this article is to provide a comprehensive review on the molecular biology of thyroid cancer focusing on the key role of tyrosine kinases. Additionally, from a clinical point of view, we provide a thorough perspective, current and future, in the treatment landscape of this tumor.

TERT Promoter Mutations and Their Impact on Gene Expression Profile in Papillary Thyroid Carcinoma

BACKGROUND

Telomerase reverse transcriptase promoter (TERTp) mutations are related to a worse prognosis in various malignancies, including papillary thyroid carcinoma (PTC). Since mechanisms responsible for the poorer outcome of TERTp(+) patients are still unknown, searching for molecular consequences of TERTp mutations in PTC was the aim of our study.

METHODS

The studied cohort consisted of 54 PTCs, among them 24 cases with distant metastases. BRAF V600E, RAS, and TERTp mutational status was evaluated in all cases. Differences in gene expression profile between TERTp(+) and TERTp(-) PTCs were examined using microarrays. The evaluation of signaling pathways and gene ontology was based on the Gene Set Enrichment Analysis.

RESULTS

Fifty-nine percent (32/54) of analyzed PTCs were positive for at least one mutation: 27 were BRAF(+), among them eight were TERTp(+), and 1 NRAS(+), whereas five other samples harbored RAS mutations. Expression of four genes significantly differed in BRAF(+)TERTp(+) and BRAF(+)TERTp(-) PTCs. Deregulation of pathways involved in key cell processes was observed.

CONCLUSIONS

TERTp mutations are related to higher PTC aggressiveness. CRABP2 gene was validated as associated with TERTp mutations. However, its potential use in diagnostics or risk stratification in PTC patients needs further studies.

Molecular Profile of Locally Aggressive Well Differentiated Thyroid Cancers

Knowledge of the genetic landscape of aggressive well differentiated thyroid cancers (WDTC) is lacking. Retrospective review of institutional database was performed to identify locally-invasive thyroid carcinomas and a comparison cohort of low-risk WDTC. ThyroSeq v2 next-generation sequencing was performed on available tissue. Survival time was analyzed by Kaplan-Meier methods and compared between groups via the log-rank test. Time to recurrence, treating death as a competing risk, was analyzed by cumulative incidence and compared between groups. Of 80 T4 tumors, 29 (36%) were met inclusion criteria, of which, 25 had genetic and clinicopathologic data. Most (24/25, 96%) harbored at least one genetic alteration, most commonly BRAF V600E (19, 76%), followed by mutations in the promoter region of TERT (14, 56%). Co-occurrence of BRAF and TERT was identified in 12 (48%) and associated with significantly higher risk of recurrence (p < 0.05). Conversely, co-occurrence of BRAF and TERT was present in only 5 of 102 (5%) patients presenting with early-stage WDTC. Compared to early-stage WDTC, co-occurrence of BRAF and TERT mutations are common in locally advanced (T4) thyroid cancer and are associated with an increased risk of recurrence. This knowledge may help predict aggressive behavior pretreatment and inform perioperative decision-making.

Contemporary considerations in adjuvant radioiodine treatment of adults with differentiated thyroid cancer

Differentiated thyroid cancer (DTC) is the most common endocrine malignancy with a growing incidence worldwide. The initial conventional management is surgery, followed by consideration of ¹³¹ I treatment that includes three options. These are termed remnant ablation (targeting benign thyroid remnant), adjuvant (targeting presumed microscopic DTC) and known disease (targeting macroscopic DTC) treatments. Some experts mostly rely on clinicopathologic assessment for recurrence risk to select patients for the ¹³¹ I treatment. Others, in addition, apply radioiodine imaging to guide their treatment planning, termed theranostics (aka theragnostics or radiotheragnostics). In patients with low-risk DTC, remnant ablation rather than adjuvant treatment is generally recommended and, in this setting, the ATA recommends a low ¹³¹ I activity. ¹³¹ I adjuvant treatment is universally recommended in patients with high-risk DTC (a primary tumor of any size with gross extrathyroidal extension) and is generally recommended in intermediate-risk DTC (primary tumor >4 cm in diameter, locoregional metastases, microscopic extrathyroidal extension, aggressive histology or vascular invasion). The optimal amount of ¹³¹ I activity for adjuvant treatment is controversial, but experts reached a consensus that the ¹³¹ I activity should be greater than that for remnant ablation. The main obstacles to establishing timely evidence through randomized clinical trials for ¹³¹ I therapy include years-to-decades delay in recurrence and low disease-specific mortality. This mini-review is intended to update oncologists on the most recent clinical, pathologic, laboratory and imaging variables, as well as on the current ¹³¹ I therapy-related definitions and management paradigms, which should optimally equip them for individualized patient guidance and treatment.

The Impact of Transcription Factor Prospero Homeobox 1 on the Regulation of Thyroid Cancer Malignancy

Transcription factor Prospero homeobox 1 (PROX1) is continuously expressed in the lymphatic endothelial cells, playing an essential role in their differentiation. Many reports have shown that PROX1 is implicated in cancer development and acts as an oncoprotein or suppressor in a tissue-dependent manner. Additionally, the PROX1 expression in many types of tumors has prognostic significance and is associated with patient outcomes. In our previous experimental studies, we showed that PROX1 is present in the thyroid cancer (THC) cells of different origins and has a high impact on follicular thyroid cancer (FTC) phenotypes, regulating migration, invasion, focal adhesion, cytoskeleton reorganization, and angiogenesis. Herein, we discuss the PROX1 transcript and protein structures, the expression pattern of PROX1 in THC specimens, and its epigenetic regulation. Next, we emphasize the biological processes and genes regulated by PROX1 in CGTH-W-1 cells, derived from squamous cell carcinoma of the thyroid gland. Finally, we discuss the interaction of PROX1 with other lymphatic factors. In our review, we aimed to highlight the importance of vascular molecules in cancer development and provide an update on the functionality of PROX1 in THC biology regulation.

Suspicious ultrasound and clinicopathological features of papillary thyroid carcinoma predict the status of TERT promoter

PURPOSE

To investigate the value of ultrasound (US) and clinicopathological features of papillary thyroid cancer (PTC) in predicting Telomerase Reverse Transcriptase (TERT) promoter mutations.

METHODS

Preoperative US images of 351 surgically confirmed PTCs were evaluated in terms of PTCs size and US features. The basic clinicopathological features were also retrieved. Univariate and multivariate analyses were performed to identify the risk factors for TERT promoter mutations. A scoring system was developed based on the cumulative number of risk factors. The area under the receiver operating characteristic curve (AUC) and cut-off value were calculated to evaluate the diagnostic performance of the scoring system for predicting TERT promoter mutations.

RESULTS

TERT promoter mutations were found in 4.84% (17/351) of patients with PTCs. Patient age >50 years (OR: 6.244, P = 0.006), multifocality (OR: 21.071, P = 0.022), taller-than-wide shape (OR: 4.934, P = 0.029), microlobulated margin (OR: 4786, P = 0.032), and capsule contact or involvement (OR: 4.668, P = 0.030) were independent risk factors for TERT promoter mutations. TERT promoter mutations were relevant to more suspicious US and clinicopathological features than TERT promoter wild-type PTC (median, 4 vs. 1, P < 0.001). The cut-off value was 2.5 and the associated AUC was 0.908 (P < 0.001).

CONCLUSIONS

The probability of TERT promoter mutations increases along with the suspicious US features and clinicopathological characteristics, which may help to recognize patients who deserve a different approach, in terms of management and follow-up, in view of the worst outcome associated to this mutation.

Association between TERT promoter mutations and clinical behaviors in differentiated thyroid carcinoma: a systematic review and meta-analysis

BACKGROUND

The association between telomerase reverse transcriptase (TERT) promoter mutations and some clinical behaviors in thyroid cancer remains controversial and requires additional investigation. This study aimed to evaluate the association between TERT promoter mutations and clinical behaviors (including clinicopathological features and prognosis) in differentiated thyroid carcinomas (DTC).

METHODS

We performed an up-to-date systematic review and current comprehensive meta-analysis. We searched three electronic databases for relevant studies. We used fixed- or random-effect models to calculate pooled estimated odds ratios (ORs) or standardized mean differences (SMDs) and corresponding 95% confidence intervals (CIs).

RESULTS

We included 51 eligible studies incorporating 11,382 cases. Average frequencies of TERT promoter mutations in DTC, papillary (PTC), and follicular (FTC) thyroid carcinomas were 10.9%, 10.6%, and 15.1%, respectively. In DTC and PTC, TERT promoter mutations were significantly associated with sex, age, tumor size, vascular invasion, extrathyroidal extension, lymph node and distant metastases, advanced tumor, nodes, and metastasis (TNM) stage, persistence/recurrence, and disease-specific mortality. In FTC, TERT promoter mutations were significantly associated with age, distant metastases, advanced TNM stage, persistence/recurrence, and disease-specific mortality.

CONCLUSIONS

TERT promoter mutations could be considered as biomarkers assisting in risk stratification, prognostic prediction, and individualizing therapeutic options for DTC (PTC and FTC).

Prognostic implications of the BRAF-V600E mutation in papillary thyroid carcinoma based on a new cut-off age stratification

The BRAF-V600^E mutation is the most common and specific oncogenic event known in papillary thyroid carcinoma (PTC). However, it remains controversial whether there is an association between the BRAF-V600^E mutation and clinicopathologically aggressive characteristics of PTC. The purpose of the present retrospective study was to investigate the significance of the BRAF-V600^E mutation in predicting prognostic and aggressive clinicopathological characteristics according to a new age-based stratification. Clinical data and the BRAF-V600^E mutation status of 475 patients with PTC were downloaded from The Cancer Genome Atlas database. The association between BRAF-V600^E status and clinicopathological characteristics was analyzed by χ² test or Fisher's exact test. Recurrence-free survival rate (RFS) was analyzed using the Kaplan-Meier method. Aggressive clinicopathological factors associated with recurrence were analyzed by Cox multivariate regression. This study was conducted on 219 cases of patients with PTC with a known BRAF-V600^E mutational status. In the ≥55 years age group, BRAF-V600^E was found to be significantly associated with aggressive PTC characteristics, including tumor size, PTC subtype, radioactive iodine (RAI) dose, follow-up time, recurrence, recurrence risk stage, advanced T stage, advanced N stage and American Joint Committee on Cancer (III/IV) stage (all P<0.05). RFS was analyzed by the log-rank test and exhibited statistically significant differences in the ≥55 years group (P=0.041), but there was no significant difference in the <55 group (P=0.757), according to the BRAF-V600^E mutation status. The BRAF-V600^E gene was excluded from the recurrence Cox multivariate regression model. The BRAF-V600^E mutation was found to better predict aggressive and recurrent PTC based on age stratification with the cut-off age of 55 years. The synergistic interaction between BRAF-V600^E mutation and the new age stratification may help clinicians reach the optimal decision in terms of surgical approach and the extent of surgery.

A novel gene panel for prediction of lymph-node metastasis and recurrence in patients with thyroid cancer

BACKGROUND

Although well-differentiated papillary thyroid cancer may remain indolent, lymph node metastases and the recurrence rates are approximately 50% and 20%, respectively. No current biomarkers are able to predict metastatic lymphadenopathy and recurrence in early stage papillary thyroid cancer. Hence, identifying prognostic biomarkers predicting cervical lymph-node metastases would prove very helpful in determining treatment.

METHODS

The database of the Cancer Genome Atlas included 495 papillary thyroid cancer samples. Using this database, we developed a machine learning model to define a gene signature that could predict lymph-node metastasis (N0 or N1). Kruskal-Wallis tests, univariate and multivariate logistic and Cox regression models, and Kaplan-Meier analyses were performed to correlate the gene signature with clinical outcomes.

RESULTS

We identified a panel of 25 genes and constructed a risk score that can differentiate N0 and N1 papillary thyroid cancer samples (P < .001) with a sensitivity of 86%, a specificity of 62%, a positive predictive value of 93%, and a negative predictive value of 42%. This panel represents an independent biomarker to predict metastatic lymphadenopathy (OR = 8.06, P < .001) specifically in patients with T1 lesions (OR = 7.65, P = .002) and disease-free survival (HR = 2.64, P = .043).

CONCLUSION

This novel 25-gene panel may be used as a potential prognostic marker for accurately predicting lymph-node metastasis and disease-free survival in patients with early-stage papillary thyroid cancer.

Prognostic Parameters in Differentiated Thyroid Carcinomas

Differentiated thyroid carcinomas make up most thyroid malignancies. The AJCC staging system and the ATA risk prediction system are the best predictors of mortality and recurrence, respectively. Key factors to be identified and reported by pathologists are reviewed in this article and include: (1) aggressive histologic variants of papillary thyroid carcinoma (including tall cell, columnar cell, and hobnail variants); (2) presence of gross extrathyroidal extension (into skeletal muscle or adjacent organs); (3) angioinvasion (including number of foci); (4) number, anatomic level, and size of lymph node metastases; (4) extranodal extension; (5) genetics (especially BRAF V600E or TERT promoter mutation).

Radioiodine-Refractory Thyroid Cancer: Molecular Basis of Redifferentiation Therapies, Management, and Novel Therapies

Recurrent, metastatic disease represents the most frequent cause of death for patients with thyroid cancer, and radioactive iodine (RAI) remains a mainstay of therapy for these patients. Unfortunately, many thyroid cancer patients have tumors that no longer trap iodine, and hence are refractory to RAI, heralding a poor prognosis. RAI-refractory (RAI-R) cancer cells result from the loss of thyroid differentiation features, such as iodide uptake and organification. This loss of differentiation features correlates with the degree of mitogen-activated protein kinase (MAPK) activation, which is higher in tumors with BRAF (B-Raf proto-oncogene) mutations than in those with RTK (receptor tyrosine kinase) or RAS (rat sarcoma) mutations. Hence, inhibition of the mitogen-activated protein kinase kinase-1 and -2 (MEK-1 and -2) downstream of RAF (rapidly accelerated fibrosarcoma) could sensitize RAI refractivity in thyroid cancer. However, a significant hurdle is the development of secondary tumor resistance (escape mechanisms) to these drugs through upregulation of tyrosine kinase receptors or another alternative signaling pathway. The sodium iodide symporter (NIS) is a plasma membrane glycoprotein, a member of solute carrier family 5A (SLC5A5), located on the basolateral surfaces of the thyroid follicular epithelial cells, which mediates active iodide transport into thyroid follicular cells. The mechanisms responsible for NIS loss of function in RAI-R thyroid cancer remains unclear. In a study of patients with recurrent thyroid cancer, expression levels of specific ribosomal machinery-namely PIGU (phosphatidylinositol glycan anchor biosynthesis class U), a subunit of the GPI (glycosylphosphatidylinositol transamidase complex-correlated with RAI avidity in radioiodine scanning, NIS levels, and biochemical response to RAI treatment. Here, we review the proposed mechanisms for RAI refractivity and the management of RAI-refractive metastatic, recurrent thyroid cancer. We also describe novel targeted systemic agents that are in use or under investigation for RAI-refractory disease, their mechanisms of action, and their adverse events.

MKL1 overexpression predicts poor prognosis in patients with papillary thyroid cancer and promotes nodal metastasis

Papillary thyroid cancer (PTC), the most common thyroid malignancy, has a strong propensity for cervical lymph node metastasis (LNM), which increases the risk of locoregional recurrence and decreases survival probability in some high-risk groups. Hence, there is a pressing requirement for a reliable biomarker to predict LNM in thyroid cancer. In the present study, MKL1 (also known as MRTFA) expression was significantly increased in PTC patients with LNM compared with those without. Further receiver operating characteristic (ROC) analysis showed that MKL1 expression had a diagnostic value in the differentiation of LNM in PTC. Furthermore, Kaplan-Meier analysis revealed that high MKL1 expression was associated with significantly decreased survival in PTC. Additionally, our study indicated that MKL1 promoted the migration and invasion of PTC cells. MKL1 interacted with and recruited Smad3 to the promoter of MMP2 to activate MMP2 transcription upon treatment with TGF-β. Moreover, there was significant correlation between expression of TGF-β, MKL1 and MMP2 in our clinical cohort of specimens from individuals with PTC. Our results suggest that the detection of MKL1 expression could be used to predict cervical LNM and inform post-operative follow-up in individuals with PTC.

Relevance and clinicopathologic relationship of BRAF V600E, TERT and NRAS mutations for papillary thyroid carcinoma patients in Northwest China

Background

To determine the relevance of the single or combination mutations of BRAF V600E, TERT, and NRAS genes and the clinicopathologic relationship in papillary thyroid cancer (PTC).

Methods

Patients with PTC were enrolled into the study between February 2018 and April 2019. Based on the number of mutant genes, we classified the participants into single BRAF V600E mutation group, double mutations group and no mutation group. Single factor and multiple logistic regression analyses were applied to explore the independent factors. Review Manager 5.3 was used for meta-analysis to review the clinical efficacy of gene co-mutations.

Results

Finally, 483 patients were enrolled into the study and 419 (86.7%) of them harbored BRAF V600E mutation. TERT or NRAS mutation was likely to coexist with BRAF V600E mutation in PTC. BRAF V600E and NRAS promoter co-mutations was identified in 6 patients, with a prevalence of 1.2%. Prevalence of BRAF V600E and TERT coexistence in PTC was 2.1%. Significant differences were found among age, pathology, multifocality, bilateral lesions, lymph node metastasis, and 131I radiotherapy, P < 0.01. Multiple logistic regression analyses demonstrated that age [odds ratio (OR) = 1.044, 95% confidence interval (CI) = 1.013–1.076; P = 0.006], lymph node metastasis [OR = 0.094, 95% CI = 0.034–0.264; P < 0.001], 131I radiotherapy [OR = 7.628, 95% CI = 2.721–21.378; P < 0.001] were risk factors for BRAF V600E mutation. Besides, age [OR = 1.135, 95% CI = 1.069–1.205; P < 0.001], multiple leisions [OR = 4.128, 95% CI = 1.026–16.614; P = 0.046], pathology [OR = 3.954, 95% CI = 1.235–12.654; P = 0.021] were independent factors for combination mutations. Meta-analysis showed significant association of BRAF V600E+/TERT+ co-mutations with lymph node metastasis, multifocality, distant metastasis, tumor recurrence, extrathyroidal extension, and dead of disease.

Conclusions

Prevalence of BRAF V600E mutation in Northwest China was higher than other areas. Age, multiple lesions, and pathology were independent factors for double mutation of BRAF V600E/TERT or BRAF V600E/NRAS. Coexistence of BRAF V600E and TERT promoter mutations was significantly correlated with poor outcome.

Molecular Study of Thyroid Cancer in World Trade Center Responders

Thyroid cancer incidence is higher in World Trade Center (WTC) responders compared with the general population. It is unclear whether this excess in thyroid cancer is associated with WTC-related exposures or if instead there is an over-diagnosis of malignant thyroid cancer among WTC first responders due to enhanced surveillance and physician bias. To maximize diagnostic yield and determine the false positive rate for malignancy, the histological diagnoses of thyroid cancer tumors from WTC responders and age, gender, and histology matched non-WTC thyroid cancer cases were evaluated using biomarkers of malignancy. Using a highly accurate panel of four biomarkers that are able to distinguish benign from malignant thyroid cancer, our results suggest that over-diagnosis by virtue of misdiagnosis of a benign tumor as malignant does not explain the increased incidence of thyroid cancer observed in WTC responders. Therefore, rather than over-diagnosis due to physician bias, the yearly screening visits by the World Trade Center Health Program are identifying true cases of thyroid cancer. Continuing regular screening of this cohort is thus warranted.

Genetic-guided Risk Assessment and Management of Thyroid Cancer

Controversies exist on how to optimally manage thyroid cancer because the prognosis is often uncertain based on clinical backgrounds. This can now be helped with prognostic genetic markers in thyroid cancer, exemplified by BRAF V600E and TERT promoter mutations, which have been well characterized and widely appreciated. The genetic duet of BRAF V600E/RAS and TERT promoter mutations is a most robust prognostic genetic pattern for poor prognosis of differentiated thyroid cancer. The high negative predictive values of the prognostic genetic markers are equally valuable. The best prognostic value of genetic markers in thyroid cancer is achieved through a clinical risk level-based and genotype-individualized manner.

Coexistence of TERT Promoter Mutations and the BRAF V600E Alteration and Its Impact on Histopathological Features of Papillary Thyroid Carcinoma in a Selected Series of Polish Patients

TERT promoter (TERTp) mutations are important factors in papillary thyroid carcinomas (PTCs). They are associated with tumor aggressiveness, recurrence, and disease-specific mortality and their use in risk stratification of PTC patients has been proposed. In this study we investigated the prevalence of TERTp mutations in a cohort of Polish patients with PTCs and the association of these mutations with histopathological factors, particularly in coexistence with the BRAF V600E mutation. A total of 189 consecutive PTC specimens with known BRAF mutational status were evaluated. TERTp mutations were detected in 8.5% of cases (16/189) with the C228T mutation being the most frequent. In six of the PTC specimens (3.2%), four additional TERTp alterations were found, which included one known polymorphism (rs2735943) and three previously unreported alterations. The association analysis revealed that the TERTp hotspot mutations were highly correlated with the presence of the BRAF V600E mutation and their coexistence was significantly associated with gender, advanced patient age, advanced disease stage, presence of lymph node metastases, larger tumor size, and tumor-capsule infiltration. While correlations were identified, the possibility of TERTp mutations being key molecular modulators responsible for PTC aggressiveness requires further studies.

Transcriptome analysis of papillary thyroid cancer harboring telomerase reverse transcriptase promoter mutation

BACKGROUND

Telomerase reverse transcriptase (TERT) promoter mutations have recently been identified as an important prognostic factor in thyroid cancer. Studies suggest that TERT may have noncanonical functions beyond telomere maintenance.

METHODS

Clinicopathological information and transcriptome data for papillary thyroid carcinoma (PTC) samples were obtained from The Cancer Genome Atlas (TCGA). Propensity score matching was performed to adjust for potential confounding variables between the TERT promoter wild-type group and the mutant group. Gene expression data of 36 patients in the mutant group were systemically compared to those of 72 patients in the wild-type group.

RESULTS

Tumors with TERT promoter mutations had a higher TERT expression. Pathways central to DNA damage responses and cell cycle regulation were significantly enriched among 888 upregulated genes. Transporter and metabolic activities were overrepresented among 799 downregulated genes. There was no difference in the expression of most of the thyroid differentiation genes.

CONCLUSION

The TERT promoter mutations were associated with proliferative and metabolic alterations in PTC.

A user's guide to non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP)

The term non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was recently introduced to replace a subset of follicular variant of papillary thyroid carcinoma (FVPTC). The goal of this change was to promote more conservative management of these tumours and spare patients the psychological burden of a cancer diagnosis. The histological diagnosis of NIFTP is stringent: the tumour needs to demonstrate encapsulation or circumscription, a purely follicular architecture and the presence of nuclear features of papillary thyroid carcinoma, while lacking capsular and vascular invasion, a significant component of solid growth and high-grade features (increased mitotic activity and necrosis). In order to ensure that these inclusion and exclusion criteria are met, the tumour must be sampled extensively, with the entire capsule/periphery submitted in all cases. When sampled by fine-needle aspiration, NIFTP is usually classified within the indeterminate categories of the Bethesda System for Reporting Thyroid Cytopathology. NIFTP is characterized genetically by frequent RAS mutations, although rarely other alterations, such as the BRAF K601E mutation and gene rearrangements in PPARG or THADA, may occur. In this review, we will examine the history of FVPTC and the findings and factors that culminated in the introduction of the NIFTP terminology. A discussion will follow with the histological, cytological and molecular characteristics of NIFTP. We will conclude by considering the potential impact of the introduction of the NIFTP terminology.

The role of TERT promoter mutations in postoperative and preoperative diagnosis and prognosis in thyroid cancer

BACKGROUND

Telomerase reverse transcriptase (TERT) promoter mutations have been described in different pathological types of thyroid cancers (TC). After many types of research focusing on the mutations rate in malignant tumors, the main role of TERT promoter mutations has been changed to the preoperative diagnosis and prognosis of TC, according to their high prevalence in aggressive TC.

METHODS

We searched Pubmed, Web of Science, Scopus, and VHL and reviewed the most common 2 mutations C288T and C250T in different types of TC, the association between them and some specific clinicopathological features, and their significance in preoperative diagnosis and prognosis of TC. we chose 38 studies into our qualitative research. We also chose 22 studies to do a meta-analysis on this subject.

RESULTS

The overall rate of these mutations in different types of TC was 10.0%, with 86.1% C228T mutation, 12% C250T mutation, and 2.1% other type mutations. The rate increases significantly as the TC become more aggressive, and reaches 56.8% in anaplastic thyroid cancer (ATC). Statistically meaningful association is found between TERT promoter mutations and older age, larger tumor size, extrathyroidal extension, lymph node metastasis, distance metastasis, advanced TNM stage, recurrence, and BRAF V600E mutation. Some studies concentrating on DNA sequencing based on fine needle aspiration biopsy (FNAB) also proved their significance in preoperative stage, with 7% to 16.5% sensitivity.

CONCLUSIONS

TERT promoter mutations were likely to occur in BRAF V600E positive TC. Patients with these 2 combined mutations were more likely to have a poor prognosis and outcome. TERT promoter mutations is an essential part of the ThySeq gene panel. The mechanism of how they influence the appearance and development of TC has not been expounded. The next study direction may be the mechanism exploration and the further study to prove their significance in preoperative diagnosis.

Regulation of mutant TERT by BRAF V600E/MAP kinase pathway through FOS/GABP in human cancer

The unique oncogene duet of coexisting BRAF V600E and TERT promoter mutations are widely found to be a robust genetic background promoting human cancer aggressiveness, but the mechanism is unclear. Here, we demonstrate that the BRAF V600E/MAP kinase pathway phosphorylates and activates FOS, which in turn acts as a transcription factor to bind and activate the GABPB promoter, increasing GABPB expression and driving formation of GABPA-GABPB complex; the latter selectively binds and activates mutant TERT promoter, upregulating TERT expression. Elevated TERT functions as a strong oncoprotein, robustly promoting aggressive behaviors of cancer cells and tumor development. We thus identify a molecular mechanism for the activation of mutant TERT by the BRAF V600E/MAP kinase pathway, in which FOS as a transcriptional factor of GABPB promoter plays a key role in functionally bridging the two oncogenes in cooperatively promoting oncogenesis, providing important cancer biological and clinical implications.

The mechanism of tumor progression robustly promoted by co-existing BRAF V600E and TERT promoter mutations is not known. Here, the authors show a mechanism of mutant TERT activation by BRAF V600E and MAPK pathways in which FOS, as a transcription factor of the GABPB promoter, functionally links the two oncogenes.

Propensity score matching analysis of the prognosis for the rare insular subtype of thyroid cancer based on SEER database

Insular thyroid carcinoma (ITC) is an uncommon thyroid malignancy with an unclear prognosis. The aim of this study was to determine the prognoses of patients with ITC. We investigated a large cohort of patients with differentiated thyroid cancer from the Surveillance, Epidemiology, and End Results (SEER) database who were registered between 2004 and 2013, and compared the prognosis of patients with ITC to those with classic papillary thyroid cancer (CPTC) and follicular thyroid cancer (FTC). Patient mortality was determined using Kaplan-Meier analyses with log-rank tests, as well as Cox proportional hazards regression analyses. The study cohort comprised of 165 patients with ITC, 5419 patients with FTC, and 60739 patients with CPTC. The rate of cancer-specific mortality per 1000 person-years for ITC was higher than that for CPTC or FTC. According to multivariate Cox regression analysis, however, the cancer-specific and all-cause mortality rates of ITC were similar to those of CPTC and FTC. The cancer-specific survival rate in patients with ITC was higher than that in patients with CPTC, but similar to that in patients with FTC, after adjusting for potentially influencing factors using propensity score matching analysis. These findings, which contrast with previously published data, provide new implications for the treatment of patients with ITC.

Prognostic implication of BRAF and TERT promoter mutation combination in papillary thyroid carcinoma-A meta-analysis

INTRODUCTION

The use of molecular markers, especially BRAF and TERT promoter mutations, for risk stratification in papillary thyroid carcinoma (PTC) is subject to continuing debate. In this study, we aimed to investigate the clinicopathological implication of each genotype when combining BRAF and TERT promoter mutations in PTCs.

METHODS

We searched four electronic databases including PubMed, Scopus, Web of Science and Virtual Health Library for relevant studies. Pooled estimates of odds ratios and corresponding 95% confidence intervals were calculated using random-effect model.

RESULTS

From 111 results, we finally included 11 studies with 3911 PTC patients for meta-analyses. Our results demonstrated that PTCs with concurrent BRAF and TERT promoter mutations were associated with increased tumour aggressiveness in comparison with PTCs harbouring BRAF or TERT promoter mutation alone. The combination of BRAF and TERT promoter mutations could classify PTCs into four distinct risk groups with decreasing aggressiveness as follows: coexisting BRAF and TERT > TERT alone=BRAF alone > no mutations.

CONCLUSION

The risk stratification of PTC based on these four genotypes can help improve the clinical management of PTCs by identifying the group of PTCs with the highest aggressiveness.

Genomic Hallmarks of Thyroid Neoplasia

The genomic landscape of thyroid cancers that are derived from follicular cells has been substantially elucidated through the coordinated application of high-throughput genomic technologies. Here, I review the common genetic alterations across the spectrum of thyroid neoplasia and present the resulting model of thyroid cancer initiation and progression. This model illustrates the striking correlation between tumor differentiation and overall somatic mutational burden, which also likely explains the highly variable clinical behavior and outcome of patients with thyroid cancers. These advances are yielding critical insights into thyroid cancer pathogenesis, which are being leveraged for the development of new diagnostic tools, prognostic and predictive biomarkers, and novel therapeutic approaches.

Do patients with oxyphilic cell papillary thyroid carcinoma have a poor prognosis? Analysis of the surveillance, epidemiology, and end results database 2004-2013 with propensity score matching

The prognosis of oxyphilic cell papillary thyroid carcinoma (OCPTC) remains unclear. The aim of this study was to investigate the prognosis of OCPTC and provide a new perspective on treatment guidelines for these patients. We investigated a large cohort of DTC patients from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2013. Patient mortality was examined by Kaplan-Meier analyses with log-rank tests and Cox proportional hazards regression analyses. In the study cohort, the rate of cancer-specific mortality per 1000 person-years for OCPTC was lower than that for classic papillary thyroid cancer (CPTC) and follicular thyroid cancer (FTC). According to the multivariate Cox regression model, the cancer-specific and all-cause mortality rates of OCPTC were similar to that of CPTC and FTC. The cancer-specific survival rate in patients with OCPTC was higher than that in patients with FTC, but similar to patients with CPTC, after matching for influential factors using propensity score matching analysis. The unanticipated prognosis provided new implications for the treatment of patients with OCPTC.

Thyrospheres from B-CPAP Cell Line with BRAF and TERT Promoter Mutations have Different Functional and Molecular Features than Parental Cells

Human thyroid cancer derived cell lines are widely used to study the mechanisms involved in thyroid carcinogenesis. However, there is limited availability of non-cross-contaminated cancer cell lines derived from papillary thyroid carcinoma (PTC), and the B-CPAP cell line is one of the few such lines. B-CPAP cells have been genetically and cytogenetically well-characterized, but details of their stemness features remain uncertain. Considering that this cell line is extensively used for in vitro studies on thyroid tumorigenesis, we broaden its functional and molecular profiles as well as the tumorigenic capacity. We used functional assays (sphere-forming capacity and efficiency), assessed self-renewal and propagation efficiency and tested in vivo tumorigenicity in Hsd:Athymic Nude-Foxn1^nu mice. Expression of markers of stemness, differentiation, and epithelial-mesenchymal transition were estimated at RNA and protein levels in adherent parental cells and sphere-forming cells. Functional aspects and stemness features were compared with normal thyrocytes. Protein expression of xenograft tumors was evaluated by immunohistochemistry. B-CPAP sphere-forming cells were able to form thyrospheres theoretically indefinitely in an appropriate serum-free medium, reverting to the adherent parental cell phenotype when cultured in differentiation medium. Different expression of ALDH1-A1 and CD44 stemness markers and TTF-1 and CK19 differentiation markers allowed discrimination between isolated sphere-forming cells and adherent parental cells, indicating that sphere-forming cells retained stem-like features. In keeping with these observations, tumorigenicity assays confirmed that, relative to parental adherent cells, thyrospheres had enhanced capacity to initiate xenograft tumors. Thyrospheres from normal cell line retained very low functional capacity, as well as different stemness markers expression compared to tumor thyrospheres. Our findings may constitute a useful background to develop an in vitro model for assessing the origin and progression of papillary thyroid carcinoma bearing BRAF^V600E and TERT promoter mutations.

A meta-analysis of prognostic roles of molecular markers in papillary thyroid carcinoma

The prognostic role of molecular markers in papillary thyroid carcinoma (PTC) is a matter of ongoing debate. The aim of our study is to investigate the impact of RAS, BRAF, TERT promoter mutations and RET/PTC rearrangements on the prognosis of PTC patients. We performed a search in four electronic databases: PubMed, Scopus, Web of Science and Virtual Health Library (VHL). Data of hazard ratio (HR) and its 95% confidence interval (CI) for disease-specific survival (DSS) and disease-free survival (DFS) were directly obtained from original papers or indirectly estimated from Kaplan-Meier curve (KMC). Pooled HRs were calculated using random-effect model weighted by inverse variance method. Publication bias was assessed by using Egger's regression test and visual inspection of funnel plots. From 2630 studies, we finally included 35 studies with 17,732 patients for meta-analyses. TERT promoter mutation was significantly associated with unfavorable DSS (HR = 7.64; 95% CI = 4.00-14.61) and DFS (HR = 2.98; 95% CI = 2.27-3.92). BRAF mutations significantly increased the risk for recurrence (HR = 1.63; 95% CI = 1.27-2.10) but not for cancer mortality (HR = 1.41; 95% CI = 0.90-2.23). In subgroup analyses, BRAF mutation only showed its prognostic value in short-/medium-term follow-up. Data regarding RAS mutations and RET/PTC fusions were insufficient for meta-analyses. TERT promoter mutation can be used as an independent and reliable marker for risk stratification and predicting patient's outcomes. The use of BRAF mutation to assess patient prognosis should be carefully considered.

Sonic Hedgehog Signaling in Thyroid Cancer

Thyroid cancer is the most common malignancy of the endocrine system. The initiation of thyroid cancer is often triggered by a genetic mutation in the phosphortidylinositol-3 kinase (PI3K) or mitogen-activated protein kinase (MAPK) pathway, such as RAS and BRAF, or by the rearrangement of growth factor receptor tyrosine kinase genes such as RET/PTC. The sonic hedgehog (Shh) pathway is evolutionarily conserved and plays an important role in the embryonic development of normal tissues and organs. Gene mutations in the Shh pathway are involved in basal cell carcinomas (BCC). Activation of the Shh pathway due to overexpression of the genes encoding the components of this pathway stimulates the growth and spread of a wide range of cancer types. The Shh pathway also plays an important role in cancer stem cell (CSC) self-renewal. GDC-0449 and LDE-225, two inhibitors of this pathway, have been approved for treating BCC and are being tested as a single agent or in combination with other drugs for treating various other cancers. Here, we review the recent findings on activation of the Shh pathway in thyroid cancer and its role in maintaining thyroid CSC self-renewal. We also summarize the recent developments on crosstalk of the Shh pathway with the MAPK and PI3K oncogenic pathways, and its implications for combination therapy.