The Frequency and Clinical Implications of the BRAF(V600E) Mutation in Papillary Thyroid Cancer Patients in Korea Over the Past Two Decades

The Association between Lymphocytic Thyroiditis and Papillary Thyroid Cancer Harboring Mutant BRAF: A Systematic Review and Meta-Analysis

Background: Papillary thyroid cancer (PTC) and lymphocytic thyroiditis (LT) co-occur with a prevalence of about 30%. PTC harboring BRAFV600E (PTC-BRAF) confers a worse prognosis, but it is unclear if LT alters prognostic features and recurrence of PTC. Objective: We compared the prevalence of PTC-BRAF with and without LT. The risk of adverse pathological features in (i) PTC in the presence and absence of BRAF mutation, irrespective of LT status, was compared to (ii) PTC in the presence and absence of LT, irrespective of BRAF status. Methods: We searched PubMed, Embase, and Web of Science Core Collection for observational studies published from 2010 to June 2023 on adult patients with PTC. The search strategy yielded 47 studies with relevant data. Data of baseline characteristics, clinicopathological features, and the quality assessment tool were extracted by two reviewers. The study was registered with PROSPERO (CRD42023437492). Results: Of the 47 studies, 39 studies with a total cohort of 28 143, demonstrated that the odds of PTC-BRAF were significantly lower in the presence of LT compared to its absence (odds ratio [OR] 0.53, 95% confidence interval [CI]: 0.48-0.58, p < 0.00001). In PTC-BRAF patients, there was a positive association of central neck nodal disease (CNND), PTC > 1 cm, extra-thyroidal extension, American Joint Committee on Cancer (AJCC) Stage 3-4, and multifocality with pooled ORs of 1.54 (95% CI: 1.16-2.04), 1.14 (95% CI: 0.82-1.58), 1.66 (95% CI: 1.40-1.97), 1.53 (95% CI: 1.35-1.75), and 1.24 (95% CI: 1.11-1.40) respectively, compared to wild-type PTC, irrespective of LT status. In the same studies, PTC with LT patients had lower pooled ORs of 0.64 (95% CI: 0.51-0.81) for CNND, 0.83 (95% CI: 0.73-0.95) for PTC > 1 cm, 0.71 (95% CI: 0.58-0.86) for ETE, 0.84 (95% CI: 0.75-0.94) for AJCC Stage 3-4 compared to PTC without LT, irrespective of BRAF status. PTC recurrence was not affected by BRAF or LT, with pooled ORs of 1.12 (95% CI: 0.66-1.90, p = 0.67) and 0.60 (95% CI: 0.28-1.30, p = 0.20) respectively. Similar results were seen with recurrence expressed as hazard ratio in this limited data-set. Conclusion: The odds of PTC-BRAF are significantly lower in the presence of LT than without. PTC with LT, irrespective of BRAF status, was significantly associated with better prognostic factors. Further studies are required to evaluate if LT inhibits PTC-BRAF, and whether this is relevant to the role of immunotherapy in advanced thyroid cancer.

Genetic alterations and allele frequency of BRAF V600E and TERT mutation in papillary thyroid carcinoma with intermediate-to-high recurrence risk: a retrospective study

The predictive value of allele frequency (AF) of BRAF V600E and TERT mutations in papillary thyroid carcinoma (PTC) remains controversial. We aimed to investigate the AF of BRAF V600E and TERT mutations in intermediate-to-high risk PTC and their association between tumor invasiveness, prognosis, and other mutations. Probe hybridization capture and high-throughput sequencing were used to quantitatively test 40 gene loci in 94 intermediate-to-high recurrence risk PTC patients, combined with clinical characteristics and follow-up for retrospective analysis. BRAF V600E mutation AF was linked to a increased risk of thyroid capsule penetration, recurrence, and concurrent mutations. Concurrent mutations could lead to a worse prognosis and increased invasiveness. TERT promoter mutation frequently accompanied other mutations and resulted in a poorer prognosis. However, there was no clear association between the TERT mutation AF and tumor invasiveness or recurrence. The sensitivity and specificity of predicting recurrence in intermediate-to-high risk PTC with BRAF V600E mutation AF > 28.2% were 60 and 80%. Although genetic alterations in PTC can differ among different ethnicities, the AF of BRAF V600E and TERT mutations may be similar. The AF of BRAF V600E has the potential to be a novel indicator in predicting PTC invasiveness and prognosis.

TERT Promoter and BRAF V600E Mutations in Papillary Thyroid Cancer: A Single-Institution Experience in Korea

Simple Summary

TERT promoter mutation has recently emerged as a promising prognostic biomarker for aggressive papillary thyroid cancer (PTC), along with BRAF B600E mutation. The prevalence of the TERT promoter mutations has been reported as relatively uncommon in Asian countries. We report on a prospective study of the TERT promoter and BRAF V600E mutation in the largest number of subjects with PTC in Korea. We assume that our specific clinical settings and the favorable healthcare environment in Korea led to several distinct findings: the lowest prevalence of TERT promoter mutation ever reported, multifocal gene mutations in bilateral PTCs, and more early-stage papillary microcarcinomas included in this study. This study indicates that relevant evaluation and treatment strategies should be investigated continuously based on different circumstances.

Abstract

Telomerase reverse transcriptase (TERT) promoter mutation has been investigated for its clinical and prognostic significance in aggressive papillary thyroid cancer (PTC). In this study, we aimed to assess the prevalence, clinicopathologic features, and treatment outcomes of TERT mutation-positive PTCs along with the common BRAF V600E mutation. We performed mutational analyses for BRAF and the TERT promoter in thyroid cancer patients who had undergone surgery at our institution since 2019. We reviewed and analyzed 7797 patients with PTC in this study. The prevalence of BRAF V600E and TERT promoter mutations was 84.0% and 1.1%, respectively. Multifocal gene mutations in bilateral PTCs were identified. TERT promoter mutations were associated with older age, larger tumor size, tumor multifocality, tumor variants, advanced stages, more adjuvant radioactive iodine treatment (RAI), higher stimulated serum thyroglobulin level before RAI, and more uptakes in the regions outside the surgical field on a post-RAI whole-body scan. The coexistence of BRAF V600E and TERT promoter mutations exacerbated all clinicopathologic characteristics. The frequency of TERT promoter mutations was the lowest in this study, compared to previous studies. TERT promoter mutations consistently correlated with aggressive PTCs, and the synergistic effect of both mutations was evident. Specific clinical settings in our institution and in Korea may have led to these distinctive results. Prospective multicenter studies with longer follow-up periods are required to establish valuable oncologic outcomes.

Diagnostic performance of next-generation sequencing and genetic profiling in thyroid nodules from a single center in China

Objective

The data regarding the mutation landscape in Chinese patients with thyroid cancer are limited. The diagnostic performance of thyroid nodules by fine-needle aspiration (FNA) cytology needs optimization, especially in indeterminate nodules.

Methods

A total of 1039 FNA and surgical resection samples tested using the targeted multigene next-generation sequencing (NGS) panel were retrospectively collected. The features of gene alterations in different thyroid tumors were analyzed, and the diagnostic efficacy was evaluated.

Results

Among 1039 samples, there were 822 FNA and 217 surgical FFPE samples. Among 207 malignant thyroid resections, a total of 181 out of 193 papillary thyroid carcinomas (PTCs) were NGS-positive (93.8%), with a high prevalence of BRAF mutations (81.9%, 158/193) and a low prevalence of RAS (1.0%, 2/193) and TERT promoter mutations (3.6%, 7/193). Gene fusions, involving the RET and NTRK3 genes, were present in 20 PTCs (10.4%) and mutually exclusive with other driver mutations. Two of three follicular thyroid carcinomas harbored multiple mutations. RET gene point mutations were common in medullary thyroid carcinoma (8/11, 72.7%). The combination of cytology and DNA-RNA-based NGS analysis demonstrated superior diagnostic value (98.0%) in FNA samples. For indeterminate thyroid nodules, the diagnostic sensitivity and specificity of NGS testing were 79.2 (38/48) and 80.0% (8/10), respectively. Two mutation-positive benign cases harbored NRAS and TSHR mutations, respectively.

Conclusions

Our study revealed the distinct molecular profile of thyroid tumors in the Chinese population. The combination of NGS testing and FNA cytology could facilitate the accurate diagnosis of thyroid nodules, especially for indeterminate nodules.

Gene Mutation Analysis in Papillary Thyroid Carcinoma Using a Multi-Gene Panel in China

Purpose

To detect low-frequency mutation in the 57 genes of small panels that are associated with developing thyroid cancer in papillary thyroid carcinoma (PTC) patients and provide patients with precise-targeted therapy.

Patients and Methods

This study included 144 patients diagnosed with PTC who underwent total thyroidectomy and lymph node dissection in the central area of the neck between May 2017 and October 2018. We performed ultra-deep sequencing of 57 genes from 144 patients and detected the 57 genes mutations with bioinformatics.

Results

There were 698 mutations in 45 genes from 138 PTC patients. A high frequency of mutations was detected in the RBM10 gene (44%) and TERT (43%), and some hotspot mutations, such as RBM10:p.E119D and TERT:p.P112fs, were also found.

Conclusion

Ultra-deep sequencing of small gene panels can find some low-frequency mutation genes, which can provide targeted therapy for patients.

The clinical usefulness of chemokine C-X-C Motif Ligand 12 as a diagnostic marker for Papillary Thyroid Carcinoma

Background

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer worldwide. It is essential to develop methods for the accurate diagnosis of PTC to avoid unnecessary surgery. The chemokine C-X-C motif ligand 12 (CXCL12) is associated with various cancers. We aimed to investigate the efficacy of CXCL12 in the diagnosis of PTC in fine-needle aspiration (FNA) specimens.

Methods

We prospectively collected samples from 58 patients who were scheduled for surgical treatment of PTC from 2013 to 2015. Tissue samples of 31 people with benign thyroid conditions were used as controls. Immunocytochemical and immunohistochemical staining for CXCL12 was performed on FNAs and corresponding tissue specimens. B-type Raf kinase (BRAF) V600E mutant protein expression and gene mutation were also analyzed to compare the clinical usefulness.

Results

: The mean age of the patients was 49.1 ± 1.4 years and 88.1% were women. Positive CXCL12 staining was observed in 6.5% of benign and in 98.3% of PTC samples; positive BRAF V600E mutant protein expression was found in 19.4% of benign and 93.1% of PTC samples. For the diagnosis of PTC for CXCL12 staining of FNA specimens, the calculated values were 93.1% sensitivity, 90.3% specificity, 94.7% positive predictive value, 87.5% negative predictive value, and 89.1% accuracy. CXCL12 had 100% sensitivity and specificity for the 12 cases of atypia of undetermined significance (AUS) diagnosed in FNA specimens.

Conclusions

CXCL12 may be a useful diagnostic tool for PTC, especially when the FNA specimen is classified as AUS.

Diagnostic and prognostic value of a 7-panel mutation testing in thyroid nodules with indeterminate cytology: the SWEETMAC study

PURPOSE

The aim of this prospective study (ClinicalTrials.gov: NCT01880203) was to evaluate the diagnostic and prognostic value of a 7-panel mutation testing in the aspirates of thyroid nodules with indeterminate cytology (IC).

METHODS

Eligible patients had a thyroid nodule ≥15 mm with IC (Bethesda III-V) for which surgery had been recommended. Detection of BRAF and RAS mutations was performed using pyrosequencing and RET/PTC and PAX8/PPARγ rearrangements using Real-Time quantitative reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Among 131 nodules with IC, 21 (16%) were malignant including 20 differentiated cancers and one thyroid lymphoma. Molecular abnormalities were identified in 15 nodules with IC corresponding to 10 malignant and 5 benign tumours. BRAF mutation was detected in 4 nodules all corresponding to classic PTC, and PAX8/PPARγ rearrangement in 2 HCC. In contrast, RAS mutation was identified in eight nodules, of which four were malignant, and one RET/PTC3 rearrangement in a follicular adenoma. This data resulted in an accuracy of 88%, sensitivity of 48%, specificity of 95%, positive-predictive value of 67%, and negative-predictive value of 91%. After a 56 month's follow-up, the proportion of excellent response was similar in patients with molecular alterations (67%) and those without (60%).

CONCLUSIONS

By increasing the overall risk of cancer from 16 to 67% in mutated nodules and by diminishing it to 9% in wild-type, this study confirms the relevance of the 7-panel mutation testing in the diagnostic of nodules with IC. Genetic testing, however, did not predict outcome in the cancer patient subgroup.

Do BRAFV600E mutation and sodium-iodide symporter expression affect the response to radioactive iodine therapy in patients with papillary thyroid carcinoma?

OBJECTIVE

To report on the associations between BRAF and sodium iodide symporter expressions and treatment outcomes in patients with papillary thyroid carcinoma.

METHODS

Inclusion criteria included a pathologic diagnosis of papillary thyroid carcinoma of any stage, thyroidectomy followed by radioactive iodine therapy, and follow-up for at least 12 months after initial therapy. Events were classified as persistent or recurrent disease based on a clinical or investigational evidence of disease within or after, respectively, 1 year from initial therapy. Disease-free survival was calculated between the dates of surgery and confirmed event. Patients with no evidence of disease were censored at their last follow-up (censored group). BRAF mutation and sodium-iodide symporter expressions were evaluated using immunohistochemistry.

RESULTS

The study included 78 patients (60 females, 18 males) with median age 36 years (range: 20-70 years). BRAF was positive in 78%, equivocal in 13%, and negative in 9%. Sodium-iodide symporter was positive in 88%. BRAF mutation was significantly associated with increasing tumor size, presence of lymphovascular invasion, classic subtype of papillary thyroid carcinoma, thyroid capsular infiltration, and lymph node metastasis. Sodium-iodide symporter expression was not associated with any clinical or pathologic characteristics. Patients with negative or equivocal BRAF had significantly better disease-free survival (82%, 3 events) compared to the positive group (41%, 33 events; P=0.02).

CONCLUSION

In patients with papillary thyroid carcinoma, BRAF mutation is associated with high-risk pathological characteristics and worsened disease-free survival.

Multi-gene assay and clinical characteristics research in papillary thyroid carcinoma

Background

To investigate the significance of multi-gene assay in papillary thyroid carcinoma (PTC) patients in clinical practice.

Methods

From April to December 2019, medical records of 68 patients with PTC after the initial surgery were retrospectively collected and analyzed in terms of the relations between gene mutations and clinicopathological characteristics.

Results

RET/PTC rearrangement was not detected in BRAF V600E mutation patients (P<0.001). Besides, compared with wild-type patients, BRAF V600E mutation was associated with significantly older age (P=0.001) and a higher rate of extrathyroid invasion (P=0.023). Significantly higher BRAF V600E mutation rates were found in clinical lymph node-negative (P=0.041) and non-metastatic lateral lymph nodes (P=0.027) patients as RET/PTC rearrangement was associated with younger age (P=0.001) and the increasing metastatic number of lymph nodes (P=0.020). Compared to other gene mutations, the multivariate analysis showed that larger tumor size [odds ratio (OR), 8.831; 95% CI: 1.971-35.578; P=0.004], the BRAF V600E mutation alone(OR, 10.567; 95% CI: 1.748-63.873; P=0.010) or in combination with one additional gene mutation (OR, 8.654; 95% CI: 1.453-68.603; P=0.041), and Hashimoto's thyroiditis (OR, 0.112; 95% CI: 0.025-0.499; P=0.004) were all independent predictors for the prevalence of ETE.

Conclusions

BRAF V600E mutation was associated with older age and the aggressiveness of PTC but was independent of lymph node metastasis (LNM). RET/PTC rearrangement suggested more LNM in young patients with PTC. BRAF V600E mutation combined with other gene mutations, namely, multi-gene mutations, could indicate a higher aggressiveness in PTC.

VE1 immunohistochemistry is an adjunct tool for detection of BRAFV600E mutation: Validation in thyroid cancer patients

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy among other endocrine tumors, and BRAF^V600E is a frequent genetic mutation occurring in the disease. Although different molecular techniques, most importantly sequencing has been widely recognized as a gold standard but molecular diagnosis remains an expensive, laborious, and time‐intensive process. Recently, immunohistochemistry (IHC) with anti‐BRAF V600E (VE1) antibody has increased practical utility and implemented clinically for the detection of BRAF^V600E mutation. Therefore, the study aimed to evaluate diagnostic accuracy of VE1 IHC for detecting the BRAF^V600E mutation frequency and clinical implementation in diagnostic laboratories. In this study, 72 formalin fixed paraffin‐embedded tissues (FFPE) were used to determine the BRAF^V600E mutation status using IHC and Sanger sequencing. The mutation was found in 29% and 28% cases using IHC and Sanger sequencing, respectively. Furthermore, the results showed 100% sensitivity, 98.07% specificity, 95.2% positive predictive value, and 100% negative predictive value. Notably, significant associations were found between BRAF^V600E status and tumor stage, tumor focality, and extrathyroidal extensions, respectively. VE1 IHC was found to be a highly sensitive, specific, and diagnostically accurate method in this cohort. Therefore, BRAF^V600E detection through IHC has been considered as the best tailored technique for routine pathology laboratories.

Prevalence of BRAFV600E mutation in Asian series of papillary thyroid carcinoma-a contemporary systematic review

Papillary thyroid carcinoma (PTC), the most common malignancy of the endocrine system, is frequently driven by BRAFV600E mutation, which was reported in 35-60% cases in Western series. Numerous studies have recently emerged from Asian countries and regions; however sufficient summary is lacking to date. BRAF mutation serves as a diagnostic and prognostic tool in thyroid cancer, therefore establishing a rate of BRAF on the national scale could be of practical significance. We performed systematic reviews of available literature to investigate the prevalence of BRAF mutation in series of PTC from various Asian countries and regions. Out of the total 3,966 reports identified via initial screening, 138 studies encompassing over 40,000 PTCs were included for the final analysis. A vast majority (90.2%) of PTCs with known BRAF status were from East Asia, including China, South Korea, and Japan, with BRAF mutation rates of 71.2%, 75.5%, and 70.6%, respectively. Less abundant Indian and Saudi Arabian series found 45.6% and 46.3% prevalence of BRAFV600E in PTC, respectively. Much limited evidence was available from Thailand, Iran, Kazakhstan, Taiwan, Singapore, Indonesia, Hong Kong, Philippines, Vietnam, Iraq, and Myanmar. No relevant publications were found from other highly populated countries, such as Pakistan, Bangladesh, and Malaysia. After grouping by geographic region, we found that the highest rate of BRAFV600E was reported in the PTC series from East Asia (76.4%). Much lower rate (45-48%) was seen in PTC cohorts from South Asia, Central Asia, and the Middle East while the Southeast Asian series were in between (57%). Further subgroup analysis revealed that studies employing fresh frozen tissue and fine-needle aspirates showed higher rates of BRAF compared to those used formalin-fixed paraffin-embedded tissues. We found that the PTC series enrolled patients' cohorts after 2010 demonstrated a higher rate of BRAF compared to the earlier series. Finally, pediatric PTCs had lower BRAF prevalence compared to the baseline rate for the country. In conclusion, despite considerable among and within countries heterogeneity, the Asian PTC series showed a higher prevalence of BRAFV600E mutation than that in Western series. Causes of geographic heterogeneity, whether genuine (etiology, genetics) or methodology-related should be further investigated.

Genomic and Transcriptomic Characteristics According to Size of Papillary Thyroid Microcarcinoma

It is controversial as to whether papillary thyroid microcarcinoma (PTMC) has some genomic and transcriptomic characteristics that differentiate between an early-stage lesion that would eventually evolve into the larger papillary thyroid cancer (PTC), and an occult indolent cancer in itself. To investigate this, we comprehensively elucidated the genomic and transcriptomic landscapes of PTMCs of different sizes, using a large-scaled database. This study included 3435 PTCs, 1985 of which were PTMCs. We performed targeted next-generation sequencing for 221 PTCs and integrated these data with the data including The Cancer Genome Atlas (TCGA) project. The frequency of v-raf murine sarcoma viral oncogene homolog B (BRAF)^V600E mutation was higher in PTMCs >0.5 cm than that in very small PTMCs (≤0.5 cm) and decreased again in PTCs >2 cm. Among PTMCs, the prevalence of mutations in rat sarcoma (RAS) and telomerase reverse transcriptase (TERT) promoter was not significantly different according to their size, but lower than in large PTCs. There was no change in the tumor mutational burden, the number of driver mutations, and transcriptomic profiles with tumor size, among PTMCs and all PTCs. Although a few genes with differential expression and TERT promoter mutations were found in a few PTMCs, our findings showed that there were no useful genomic or transcriptomic characteristics for the prediction of the future progression of PTMC.

Is a simplified TNM staging system more clinically relevant than the American Joint Committee on Cancer system for the follicular variant of papillary thyroid cancer?

BACKGROUND

Despite the recent release of the 8th edition of the American Joint Committee on Cancer (AJCC) staging manual, risk stratification for the follicular variant of papillary thyroid cancer (FVPTC), which is the second common variant of papillary thyroid carcinoma (PTC) after classical PTC, remains controversial. This study aimed to develop a more accurate and relevant staging system specifically for FVPTC.

METHODS

Patients with FVPTC who were included in the Surveillance, Epidemiology, and End Results (SEER) open database between 2010 and 2015 were divided into 47 groups according to their TNM classifications and age. Subsequently, these 47 groups were categorized into appropriate stages based on Kaplan-Meier survival curves, mortality analyses, a Cox proportional hazards model, and clinical considerations.

RESULTS

Our retrospective analysis of 17,628 cases yielded the following new staging classification: stage I, defined as age <55 years and any T/N/M or age ≥55 years and T1-3/any N/M0 (n=17,427, 98.85%); stage II, age ≥55 and T4/any N/M0 or age ≥55 and any T/N0/M1 (n=173, 0.99%); and stage III, age ≥55 and any T/N1/M1 (n=28, 0.16%). The overall mortality rates per 1,000-person-years were 4.135 [95% confidence interval (CI): 3.653-4.681], 71.193 (95% CI: 51.354-98.697), and 199.744 (95% CI: 115.983-343.997) for our new stages I, II, and III, respectively. The hazard ratios for the new stages II and III (reference: stage I) were 5.081 (95% CI: 3.110-8.301) and 21.690 (95% CI: 11.402-41.258), respectively.

CONCLUSIONS

Compared to the 8th edition of the AJCC staging system, our newly proposed system provided more accurate risk stratification for patients with FVPTC, as demonstrated by actual survival and mortality outcomes. This new model may thus help guide more personalized treatment for these patients.

The role of Slit2 as a tumor suppressor in thyroid cancer

Slits, representative axon guidance molecules, and their Roundabout (Robo) transmembrane receptors play roles in the progression of many cancers. We investigated the effects of Slit2 on the proliferation, migration, and invasion of thyroid cancer cells, and on the prognosis of papillary thyroid cancer (PTC). Slit2 overexpression inhibited the proliferation, migration and invasion of thyroid cancer cells by inhibiting transcriptional activity of beta-catenin and regulating Rho GTPase activity. Slit2 knockdown activated the migration and invasion of thyroid cancer cells and transcriptional activity of beta-catenin. Fragment Slit2 treatment inhibited thyroid cancer cell proliferation in a dose dependent manner, and also inhibited migration and invasion. When we evaluated the protein expression of Slit2 in PTCs, 24 of 160 PTCs (15%) were negative for Slit2 protein expression and these patients had significantly increased risk of cervical lymph node metastasis (P < 0.001), distant metastasis (P < 0.001) and recurrence of PTC (P < 0.001). Our findings suggest a role for Slit2 as a tumor suppressor, and also as a novel prognostic and potential therapeutic target for thyroid cancer.

BRAF mutation in papillary thyroid cancer-Prevalence and clinical correlation in a South-East Asian cohort

OBJECTIVE

BRAF mutation is the commonest mutation seen in papillary thyroid cancer (PTC), but its prevalence and clinical significance vary across countries. We aim to evaluate the prevalence and clinico-pathological correlation of BRAF mutation in PTC patients at our centre.

STUDY DESIGN

Retrospective cohort study of 75 consecutive archival thyroid specimens, whereby BRAF mutation was detected using a polymerase chain reaction (PCR) technique and correlated with clinical and pathological features and outcomes.

SETTING

Tertiary university hospital in Singapore.

PARTICIPANTS

A total of 75 consecutive histologically proven archival thyroid specimens from patients who underwent thyroidectomy for PTC were accrued for this study.

MAIN OUTCOME MEASURES

Main outcome is to determine the prevalence of the BRAF mutation in our South-East Asian population. Secondary aim is to correlate the mutational status with adverse pathological features like histological variants, multi-focality, lymphovascular invasion and extra-thyroidal extension, clinical features like demographics, TNM stage, recurrence and survival, as well as treatment details like type of surgery performed and radioiodine doses.

RESULTS

BRAF mutation was detected in 56% (42/75) of PTC. All but one BRAF-mutated PTC had the BRAFV600E mutation. BRAF-mutated tumours were associated with an advanced T-stage (P = 0.049) and were more likely to have a central neck dissection (P = 0.036). There was no significant correlation between BRAF mutation status and clinical outcomes.

CONCLUSION

The prevalence of BRAF mutation is 56%. BRAF mutation-positive tumours were associated with locally advanced disease, but not poorer survival.

Case-Control Study of Papillary Thyroid Carcinoma on Urinary and Dietary Iodine Status in South Korea

BACKGROUND

The association between iodine levels and the risk of papillary thyroid cancer (PTC) has been suggested, but not definitively established. This study is to compare the iodine status of a group of patients with PTC (with and without BRAF ^V600E) with that of a healthy population cohort.

METHODS

A cohort of patients scheduled for thyroidectomy was enrolled, along with a community-based health-screening cohort with no known history of thyroid disease. Median urinary iodine (UI) levels, creatinine-adjusted median UI levels, and food frequency questionnaire (FFQ) scores (mean ± SD) were compared. In a subgroup analysis, these values were compared between BRAF ^V600E-positive and BRAF ^V600E-negative patients in the PTC group.

RESULTS

The PTC group consisted of 210 patients, and the control group consisted of 90 healthy individuals. Among the 191 PTC patients whose BRAF ^V600E mutational status was reported, 169 (88.5%) were revealed positive for the mutation. The median UI levels were significantly higher in the PTC group (786.0 μg/l) than the control group (112.0 μg/l; p < 0.001), as was the case with creatinine-adjusted median UI levels (884.6 μg/g creatinine versus 182.0 μg/g creatinine; p < 0.001) and FFQ scores (66.2 ± 17.5, range 13-114 versus 54.6 ± 21.5, range 16-134; p < 0.001). No significant differences were seen in the subgroup analysis between BRAF ^V600E-positive and BRAF ^V600E-negative patients.

CONCLUSIONS

Our results indicate that iodine status differs significantly between patients with PTC and healthy controls, suggesting that iodine may be involved in the occurrence of PTC, although the association between iodine levels and BRAF mutational status did not reach statistical significance.

Prevalence of BRAFV600E Mutation in Follicular Variant of Papillary Thyroid Carcinoma and Non-Invasive Follicular Tumor with Papillary-Like Nuclear Features (NIFTP) in a BRAFV600E Prevalent Area

BACKGROUND

BRAF^V600E mutation status and prevalence of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) has not yet been reported in Korea. The aim of this study was to investigate the significance of the BRAF^V600E mutation in the follicular variant of papillary thyroid carcinoma (FVPTC) and to determine the prevalence of NIFTP in BRAF^V600E mutation-prevalent Korean patients.

METHODS

This study retrospectively analyzed 1,417 consecutive patients who underwent total thyroidectomy with routine prophylactic central lymph node dissection for papillary thyroid carcinoma (PTC). BRAF^V600E mutation analysis was performed routinely using multiplex polymerase chain reaction by applying dual priming oligonucleotide. Clinicopathological characteristics and ultrasonographic findings were compared between BRAF^V600E mutation-positive and -negative groups for FVPTC. Pathologists reviewed the pathology slides according to consensus diagnostic criteria for the encapsulated FVPTC and NIFTP.

RESULTS

The prevalence of the BRAF^V600E mutation in all subtypes of PTC was 61.0% (861/1,411). FVPTC presented a BRAF^V600E mutation rate of 27.3%. The FVPTC patients with BRAF^V600E mutation were older than those with no BRAF^V600E mutation (P = 0.021). The prevalence of NIFTP was 0.18% among all PTC patients (2/1,411) and the proportion of NIFTP among FVPTC was 9.1% (2/22).

CONCLUSION

The BRAF^V600E mutation is prevalent in Korean patients with FVPTC in a region with high frequency of the BRAF^V600E mutation and very low prevalence of NIFTP compared with that reported in western studies.

Clinical Characteristics of Subtypes of Follicular Variant Papillary Thyroid Carcinoma

BACKGROUND

Among follicular variant papillary thyroid carcinomas (FVPTCs), the noninvasive encapsulated subtype has an excellent prognosis. For this reason, reclassification of noninvasive encapsulated FVPTC (EFVPTC) as a new entity called "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) has been proposed, but controversy remains. To characterize noninvasive EFVPTC in an Asian population, the clinicopathologic features of each FVPTC subtype were compared in a Korean population.

METHODS

FVPTC patients (n = 142) who underwent thyroidectomy between 2009 and 2014, and whose tumor size was >1 cm, were included in the study. The surgical pathology of each patient was reevaluated by two independent expert pathologists.

RESULTS

The percentages of noninvasive and invasive EFVPTC and infiltrative FVPTC (IFVPTC) in the study were 30%, 31%, and 39%, respectively. There was no difference in preoperative cytological diagnosis or the extent of surgery between noninvasive and invasive EFVPTC. However, the proportion of Bethesda category IV was lower in IFVPTC (16%) than in noninvasive and invasive EFVPTC (35% and 36%, respectively). Therefore, thyroid lobectomy was more common in noninvasive or invasive EFVPTC (54% or 48%, respectively) than in IFVPTC (16%). Noninvasive EFVPTC showed lower multiplicity, extrathyroidal extension, and BRAF^V600E mutation frequency (three cases; 8%) than did invasive EFVPTC, but other pathological characteristics were similar. However, IFVPTC showed significant differences in tumor size, extrathyroidal extension, lymph node metastasis, Tumor Node Metastasis stage, and American Thyroid Association high-risk category compared with noninvasive and invasive EFVPTC. In the noninvasive EFVPTC group, there were six (14%) cases with multifocality and three (7%) cases with lymph node metastasis. However, only two cases with multifocality and one case with lymph node metastasis originated from noninvasive FVPTC, while the other cases were from coexisting conventional PTCs.

CONCLUSIONS

Noninvasive EFVPTC has favorable pathological features, but lymph node metastasis or BRAF^V600E mutations were observed in some patients. Therefore, in order for the distinction between noninvasive EFVPTC and invasive EFVPTC to have more clinical significance, the criteria for NIFTP need to be more strictly revised.

Co-existence of BRAFV600E and TERT promoter mutations in papillary thyroid carcinoma is associated with tumor aggressiveness, but not with lymph node metastasis

BACKGROUND

Mutations of BRAF^V600E and TERT promoters are associated with thyroid cancer development. This study further investigated association of these mutations with clinicopathological characteristics from patients with papillary thyroid carcinoma (PTC).

METHODS

Tumor tissues from 342 PTC patients were obtained for DNA extraction and polymerase chain reaction amplification to detect the BRAF^V600E mutation using amplification-refractory mutation system-polymerase chain reaction. TERT promoter mutations were assessed using Sanger DNA sequencing. The association of these gene mutations with clinicopathological characteristics was then statistically analyzed.

RESULTS

Two hundred and seventy of 342 (78.9%) PTC patients harbored the BRAF^V600E mutation, which was associated with older age male patients. Moreover, TERT promoter mutations occurred in 12 of 342 (3.5 %) PTC patients, all of whom also had the BRAF mutation. One hundred thirty-three patients with papillary thyroid microcarcinoma (PTMC) had no TERT mutations. Statistically, the coexistence of BRAF and TERT promoter mutations were significantly associated with older age, larger tumor size, extrathyroidal extension, and advanced tumor stage, but not with central lymph node metastasis, lateral lymph node metastasis, numbers of lymph node metastasis >5, and numbers of involved/harvested lymph nodes (No. of LNs involved or harvested). The multivariate analyses showed older age (odds ratio [OR], 2.194; 95% CI: 1.117-4.311; p=0.023), larger tumor size (OR, 4.100; 95% CI: 2.257-7.450; p<0.001), and multiplicity (OR, 2.240; 95% CI: 1.309-3.831; p=0.003) were all independent predictors for high prevalence of extrathyroidal extension. However, there was no statistical association with any clinicopathological characteristics except for Hashimoto thyroiditis in PTMC.

CONCLUSION

The current study demonstrated that the coexistence of BRAF and TERT promoter mutations were associated with the PTC aggressiveness, although these mutations were not associated with PTC lymph node metastasis or with PTMC.

Genetic landscape of papillary thyroid carcinoma in the Chinese population

Improvement in the clinical outcome of human cancers requires characterization of the genetic alterations underlying their pathogenesis. Large-scale genomic and transcriptomic characterization of papillary thyroid carcinomas (PTCs) in Western populations has revealed multiple oncogenic drivers which are essential for understanding pathogenic mechanisms of this disease, while, so far, the genetic landscape in Chinese patients with PTC remains uncharacterized. Here, we conducted a large-scale genetic analysis of PTCs from patients in China to determine the mutational landscape of this cancer. By performing targeted DNA amplicon and targeted RNA deep-sequencing, we elucidated the landscape of somatic genetic alterations in 355 Chinese patients with PTC. A total of 88.7% of PTCs were found to harbor at least one candidate oncogenic driver genetic alteration. Among them, around 72.4% of the cases carried BRAF mutations; 2.8% of cases harbored RAS mutations; and 13.8% of cases were characterized with in-frame gene fusions, including seven newly identified kinase gene fusions. TERT promoter mutations were likely to occur in a sub-clonal manner in our PTC cohort. The prevalence of somatic genetic alterations in PTC was significantly different between our Chinese cohort and TCGA datasets for American patients. Additionally, combined analyses of genetic alterations and clinicopathologic features demonstrated that kinase gene fusion was associated with younger age at diagnosis, larger tumor size, and lymph node metastasis in PTC. With the analyses of DNA rearrangement sites of RET gene fusions in PTC, signatures of chromosome translocations related to RET fusion events were also depicted. Collectively, our results provide fundamental insight into the pathogenesis of PTC in the Chinese population. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Changes in the clinicopathological characteristics and genetic alterations of follicular thyroid cancer

OBJECTIVE

Changes in the clinicopathological characteristics and genetic alterations of follicular thyroid cancer (FTC) over time have not been reported. Moreover, the prognostic effects of RAS and TERT promoter mutations in FTC have not been clearly elucidated. We investigated changes in the clinicopathological characteristics of patients with FTC over four decades, as well as the clinical significance of genetic mutations of FTC.

DESIGN AND METHODS

This retrospective study included 690 patients with FTC who underwent thyroidectomy between 1973 and 2015 at the Seoul National University Hospital. In 134 samples, genetic tests for N/H/KRAS and TERT promoter mutations and PAX8/PPARγ rearrangement were performed.

RESULTS

The age at diagnosis has increased (P < 0.001) in recent decades and extrathyroidal extension of the tumor has become less common (P = 0.033). Other clinicopathological characteristics and prognosis of FTC have not significantly changed. The prevalence of RAS mutations decreased (P = 0.042) over time, whereas that of TERT promoter mutations remained stable. RAS mutations were associated with distant metastasis and persistent disease, and TERT promoter mutations were associated with distant metastasis, advanced TNM stage, recurrence and disease-specific mortality. FTC patients with coexistent RAS and TERT promoter mutations showed a higher recurrence risk than those with only one mutation.

CONCLUSIONS

The age at diagnosis of FTC and the frequency of extrathyroidal extension have changed over four decades. Moreover, the prevalence of RAS mutations decreased. RAS and TERT promoter mutations may be associated with poor clinical outcomes in FTC, especially when the two mutations coexist.

Current trends of practical issues concerning micropapillary thyroid carcinoma: The Korean Society of Thyroid-Head and Neck Surgery

Although several thyroid associations have published various guidelines, controversies especially in cases of micropapillary thyroid cancer (MPTC) still exist. This survey was designed to collect information about diagnostic tests and treatments performed on patients with MPTC and help identify current trends in thyroid surgery.We developed questionnaires about the management methods for MPTC, which were used to identify factors related to indications of fine needle aspiration (FNA), type of surgery, and central lymph node dissection (CLND). Active 60 members of the Korean Society of Thyroid-Head and Neck Surgery participated in the study in September 2016.Ultrasound-guided FNA was usually initiated when the tumor was at least 5 mm (60%). All respondents preferred ultrasound-guided FNA and surgery for nodules with extrathyroidal extension (ETE). The preferred treatment option for intraglandular MPTC was lobectomy (92%) rather than active surveillance (8%). Posterolateral ETE increased the respondents' preference for total thyroidectomy (61.7%). Active surveillance was preferred for tumors <5 mm, which was decreased by the presence of ETE. The presence of ETE (73.3%) and its proximity to critical organs (46.7%) were the main determining factors for prophylactic CLND. For multiple metastatic lymph nodes at level III, selective neck dissection including levels IIb (23.3%) and V (78.3%) was preferred in addition to levels IIa, III, VI, and V.Korean head and neck surgeons favored total thyroidectomy and CLND in cases wherein ETE, central lymph node metastasis, or critical organ involvement was suspected.

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.

Dynamic Risk Stratification for Predicting Recurrence in Patients with Differentiated Thyroid Cancer Treated Without Radioactive Iodine Remnant Ablation Therapy

BACKGROUND

Increased incidence of small differentiated thyroid cancer (DTC) has emphasized the need for risk stratification and individualized disease management for these low risk DTCs. The aim of this study was to validate a new dynamic risk stratification (DRS) system for the prediction of structural recurrent/persistent disease in patients with DTC treated without radioactive iodine (RAI) remnant ablation therapy.

METHODS

This historical cohort study included 357 patients with DTC treated with lobectomy or total thyroidectomy without RAI therapy. We stratified patient response to initial treatment as excellent, indeterminate, biochemical incomplete, and structural incomplete according to the DRS system.

RESULTS

During a median follow-up of 8.6 years, 3.6% patients had structural recurrent DTC. The response was excellent in 71.7% patients, indeterminate in 18.5%, biochemical incomplete in 8.4%, and structural incomplete in 1.4%. There were significant differences in DFS among the DRS groups (p < 0.001). The hazard ratio (HR) of recurrent/persistent disease was significantly higher in the biochemical incomplete group (HR = 20.8, p < 0.001) and structural incomplete group (HR = 243.3, p < 0.001) compared with the excellent group. However, the Tumor Node Metastasis staging system and the American Thyroid Association initial risk classification did not effectively predict recurrence of DTC.

CONCLUSIONS

The new DRS system was effective for predicting risk of recurrent/persistent disease in patients with DTC who underwent lobectomy or total thyroidectomy without RAI remnant ablation.

The changing characteristics and molecular profiles of papillary thyroid carcinoma over time: a systematic review

BACKGROUND

The genetic alterations of papillary thyroid carcinoma (PTC) have been reported to change over the past few decades. We performed this systematic review to further examine the trends and modifications of patient demographic, clinicopathological features and molecular profiles of PTC over time.

METHODS

A literature search was performed within six electronic databases to identify relevant articles. The inclusion criteria were published studies investigating BRAF mutations, RET/PTC rearrangements or RAS mutations in PTCs or classical PTCs. Two teams of reviewers independently screened titles and abstracts of all articles. Full texts of potential articles were read and extracted data were listed and stratified into an excel file according to country, city, institution, and surgical time period. Student t test and Pearson Chi-square were used to analyze the trends of demographic and clinicopathological features of PTC patients and the prevalence of each genetic alteration in individual institutions.

RESULTS

From 3139 articles, we included 16 articles for final analysis. Our results showed an increasing trend of BRAF and a decreasing trend of RET/PTC prevalence over time in PTCs and classical PTCs, accompanied by an older age of PTC patients, an increase in proportion of PTMC and less aggressive behaviours of tumours.

CONCLUSIONS

The demographic and clinicopathological characteristics and molecular profile of PTCs have been changing over the past few decades. These modifications suggest changes in etiologies and risk factors of thyroid cancer that influence the tumorigenesis of PTCs.

Genetic Alterations and Their Clinical Implications in High-Recurrence Risk Papillary Thyroid Cancer

Purpose

Papillary thyroid carcinomas (PTCs) frequently involve genetic alterations. The objective of this study was to investigate genetic alterations and further explore the relationships between these genetic alterations and clinicopathological characteristics in a high-recurrence risk (node positive, N1) PTC group.

Materials and Methods

Tumor tissue blocks were obtained from 240 surgically resected patients with histologically confirmed stage III/IV (pT3/4 or N1) PTCs. We screened gene fusions using NanoString’s nCounter technology and mutational analysis was performed by direct DNA sequencing. Data describing the clinicopathological characteristics and clinical courses were retrospectively collected.

Results

Of the 240 PTC patients, 207 (86.3%) had at least one genetic alteration, including BRAF mutation in 190 patients (79.2%), PIK3CA mutation in 25 patients (10.4%), NTRK1/3 fusion in six patients (2.5%), and RET fusion in 24 patients (10.0%). Concomitant presence of more than two genetic alterations was seen in 36 patients (15%). PTCs harboring BRAF mutation were associated with RET wild-type expression (p=0.001). RET fusion genes have been found to occur with significantly higher frequency in N1b stage patients (p=0.003) or groups of patients aged 45 years or older (p=0.031); however, no significant correlation was found between other genetic alterations. There was no trend toward favorable recurrence-free survival or overall survival among patients lacking genetic alterations.

Conclusion

In the selected high-recurrence risk PTC group, most patients had more than one genetic alteration. However, these known alterations could not entirely account for clinicopathological features of high-recurrence risk PTC.

Molecular Diagnosis Using Residual Liquid-Based Cytology Materials for Patients with Nondiagnostic or Indeterminate Thyroid Nodules

BACKGROUND

Molecular analysis for common somatic mutations in thyroid cancer can improve diagnostic accuracy of fine-needle aspiration cytology (FNAC) in the nondiagnostic or indeterminate category of thyroid nodules. In this study, we evaluated the feasibility of molecular diagnosis from residual liquid-based cytology (LBC) material after cytological diagnosis.

METHODS

This prospective study enrolled 53 patients with thyroid nodules diagnosed as nondiagnostic, atypia of undetermined significance (AUS), or follicular lesion of undetermined significance (FLUS) after FNAC. DNAs and RNAs were isolated from residual LBC materials. BRAF(V600E) and RAS point mutations, PAX8/peroxisome proliferator-activated receptor γ (PPARγ), RET/PTC1, and RET/PTC3 rearrangements were evaluated by real-time polymerase chain reaction and pyrosequencing.

RESULTS

All DNAs from 53 residual LBC samples could be analysed and point mutations were detected in 10 samples (19%). In 17 AUS nodules, seven samples (41%) had point mutations including BRAF (n=4), NRAS (n=2), and KRAS (n=1). In 20 FLUS nodules, three samples (15%) had NRAS point mutations. RNA from only one FLUS nodule could be analysed for rearrangements and there was no abnormality.

CONCLUSION

Molecular analysis for BRAF and RAS mutations was feasible in residual LBC materials and might be useful for diagnosis of indeterminate thyroid nodules.

BRAF and epithelial-mesenchymal transition in papillary thyroid carcinoma - challenging the roles of Snail and E-Cadherin?

OBJECTIVE

In papillary thyroid carcinoma (PTC), while the role of BRAF is well established, the contribution of BRAF to epithelial-mesenchymal transition is not.

STUDY DESIGN/SETTING

To elucidate the relationship between BRAF, surrogates of epithelial-mesenchymal transition (Snail, E-cadherin) and established histopathologic prognosticators in papillary thyroid carcinoma.

SUBJECTS/METHODS

In this IRB approved cross-sectional study, 50 cases of archived annotated PTC samples were retrieved and immunohistochemically stained for Snail and E-cadherin protein. A semi-quantitative scoring system (incorporating proportion and intensity) was utilized.

RESULTS

Snail and E-cadherin expression were noted in 44% and 84% of BRAF mutant and, in 29% and 95% of BRAFWT samples, respectively. No statistically significant correlations were noted between Snail, E-cadherin and histopathologic prognosticators. However, a trend was noted between Snail expression and tumor size <5 cm (P=0.07). Statistically significant differences between BRAF mutant and BRAFWT samples were noted in the following groups: conventional (68% vs. 5%) and tall cell (32% vs. 0%) histopathologic variants, extrathyroidal extension (32% vs. 5%), infiltrative growth pattern (80% vs. 48%), presence of desmoplasia (72% vs. 29%), psammona bodies (48% vs. 10%), and cystic change (32% vs. 5%). Among follicular variant of papillary thyroid carcinoma compared to BRAF mutant samples, BRAFWT samples were more commonly of the encapsulated variety (52% vs. 4%), and microcarcinomas (29% vs. 0%) (P<0.001 and =0.007, respectively).

CONCLUSION

Our findings, supporting the utility of BRAF as a putative therapeutic target in PTC, suggest that the interaction between BRAF and epithelial-mesenchymal transition in papillary thyroid carcinoma is not through induction of the Snail/E-cadherin pathway.

Associations between BRAF(V600E) and prognostic factors and poor outcomes in papillary thyroid carcinoma: a meta-analysis

Background

The objective of this study is to perform a meta-analysis to evaluate the associations between the BRAF^V600E mutation status and aggressive clinicopathological features and poor prognostic factors in papillary thyroid cancer.

Methods

A literature search was performed within the PubMed, MEDLINE, Web of Science databases, and EMBASE databases using the Medical Subject Headings and keywords from January 2003 to July 2015. Individual study-specific odds ratios and confidence intervals were calculated, as were the Mantel-Haenszel pooled odds ratios for the combined studies.

Results

Sixty-three studies of 20,764 patients were included in the final analysis. Compared with wild-type BRAF, the BRAF^V600E mutation was associated with aggressive clinicopathological factors, including extrathyroidal extension, higher TNM stage, lymph node metastasis, and recurrence, and was associated with reduced overall survival; however, there was no significant association between the presence of BRAF mutation and distant metastasis.

Conclusions

BRAF mutations are closely associated with aggressive clinicopathological characteristics and poorer prognosis in papillary thyroid cancer. Accordingly, aggressive treatment should be considered for papillary thyroid cancer patients with BRAF mutation.

BRAF and Epithelial-Mesenchymal Transition: Lessons From Papillary Thyroid Carcinoma and Primary Cutaneous Melanoma

The increased prevalence of BRAF mutations in thyroid carcinoma and primary cutaneous melanoma (PCM) hint that dysregulation of BRAF might contribute to the noted association between PCM and thyroid carcinoma. A recent study evaluating the rate of BRAFV600E mutations among patients who had been diagnosed with primary papillary thyroid carcinoma (PTC) and PCM showed that patients with either PCM or PTC were at an increased risk of developing the other as a second primary malignant neoplasm. Furthermore, the authors noted that samples from patients suffering from both malignancies exhibited a higher rate of incidence of the BRAFV600E mutation, compared with patients not suffering from both malignancies. These studies support the hypothesis that the pathogenesis of these 2 malignancies might share a conserved molecular pattern associated with dysregulation of the BRAF protein. One mechanism through which BRAF might contribute to PCM and thyroid carcinoma progression is through induction of epithelial-mesenchymal transition (EMT). Specifically, the Snail/E-cadherin axis has been demonstrated as a pathway dysregulated by BRAF, leading to EMT in both malignancies. Our analysis focuses on the results of these recent investigations, and through a review of select molecules relevant to EMT, looks to provide a context by which to better understand the relevance and role of stromal-parenchymal signaling and the BRAF mutation in the pathogenesis of PTC and PCM.

Prognostic Significance of TERT Promoter Mutations in Papillary Thyroid Carcinomas in a BRAF(V600E) Mutation-Prevalent Population

BACKGROUND

The role of telomerase reverse transcriptase (TERT) promoter mutations in differentiated thyroid cancer has been well established. These mutations have a significantly higher prevalence in aggressive thyroid tumors, including widely invasive oncocytic carcinomas, poorly differentiated carcinomas, and anaplastic thyroid carcinomas. Interestingly, in some studies, TERT mutations were found to be more common in tumors with a BRAF(V600E) mutation. However, mutational analysis of TERT promoter mutations in thyroid tumors has not been previously performed for patients in Korea, where the BRAF(V600E) mutation in papillary thyroid carcinoma (PTC) is particularly prevalent. This study analyzed TERT promoter mutations in various thyroid tumors and examined their relationship with clinicopathologic factors and the BRAF(V600E) mutation in PTC cases.

METHODS

Using 242 preoperative fine-needle aspiration biopsy specimens (including 207 PTCs) with confirmed histopathological diagnosis of the biopsied thyroid nodules, the TERT promoter status (C228T and C250T) was analyzed, and the relationship with clinicopathologic factors and the BRAF(V600E) mutation in PTC cases was examined.

RESULTS

Of 242 patients, 14.5% (30/207), 26.7% (4/15), 50% (1/2), and 60% (2/5) of PTCs, follicular thyroid carcinomas, poorly differentiated carcinomas, and anaplastic thyroid carcinomas harbored a TERT(C228T) mutation, respectively. The TERT(C228T) mutation was associated with recurrence (p = 0.03). However, no association with other clinicopathologic factors in PTC was found. Coexistence of TERT(C228T) and BRAF(V600E) mutations was found in 13.0% of PTCs and was significantly associated with older age and advanced stage compared with the group negative for either mutation. The TERT(C228T) mutation status was an independent prognostic factor for recurrence-free survival (hazard ratio = 3.08 [confidence interval 1.042-9.079]; p = 0.042) in patients with PTC in multivariate analysis.

CONCLUSIONS

Identification of TERT promoter mutations in preoperative fine-needle aspiration biopsy specimens may help in better characterizing the prognosis and triaging thyroid cancer patients for appropriate treatment.

Genetic alterations of differentiated thyroid carcinoma in iodine-rich and iodine-deficient countries

BRAF V600E mutation, RET rearrangements, and RAS mutations are the common genetic alterations in differentiated thyroid carcinomas derived from follicular thyroid cells. However, the relationship between these alterations and iodine intake is still controversial. To clarify the influence of iodine intake on the occurrence of differentiated thyroid carcinomas, we performed molecular analyses for two differentiated carcinomas, papillary thyroid carcinomas (PTCs) and follicular thyroid carcinomas (FTCs), from an iodine-rich country (Japan) and an iodine-deficient country (Vietnam). We examined 120 PTCs (67 Japanese and 53 Vietnamese) and 74 FTCs (51 Japanese and 23 Vietnamese). We carried out allele-specific polymerase chain reaction (AS-PCR) for BRAF V600E, PCR and direct sequencing for RAS mutations (codon 12, 13, and 61 in NRAS, HRAS, and KRAS), and RT-PCR for RET/PTC1 and RET/PTC3. BRAF V600E was present in 55/67 (82.1%) Japanese PTCs and 44/53 (83%) Vietnamese PTCs. RET/PTC1 was identified in only one PTC from each country, and no samples had RET/PTC3. NRAS mutation was found in 17/51 (33.3%) Japanese FTCs and 4/23 (17.4%) Vietnamese FTCs. NRAS mutation was cited in codon 61 (20 cases) and codon 12 (one case). None of FTCs had KRAS or HRAS mutations. There were no significant differences in the prevalence of BRAF V600E, RET/PTC, or RAS mutations between the two countries. Our study showed no differences in genetic alterations of thyroid cancers from iodine-rich and iodine-deficient countries, possibly suggesting that iodine intake might not affect the genetic alterations of differentiated thyroid cancer.

Genomic Alterations of Anaplastic Thyroid Carcinoma Detected by Targeted Massive Parallel Sequencing in a BRAF(V600E) Mutation-Prevalent Area

BACKGROUND

Anaplastic thyroid carcinoma (ATC), the most aggressive type of thyroid cancer, has no effective therapy. Due to its dismal prognosis, it is vital to understand the genetic alterations of ATC and identify effective molecular targets. Targeted next-generation sequencing was performed to investigate the mutational profile of ATC using a massive parallel sequencing approach.

METHODS

DNA from formalin-fixed, paraffin-embedded archival samples of 11 ATCs and normal matched pairs were used. A total of 48 genetic alterations were identified by targeted exome sequencing. These alterations were validated by mass spectrometric genotyping and direct Sanger sequencing.

RESULTS

The most commonly mutated gene was BRAF, identified in 10 samples (91%), all showing the V600E point mutation. A KRAS point mutation was observed in the one sample (9%) without the BRAF(V600E) mutation. All 11 ATCs harbored BRAF or RAS mutations, reflecting the possibility that differentiated thyroid carcinomas progress to ATCs after the accumulation of mutations. A loss of function mutation of TP53 was observed in eight samples (73%), a PIK3CA mutation was observed in two samples (18%), and a frameshift mutation of PTEN was observed in one sample (9%). Twenty-eight novel mutated genes were found that had not previously been associated with ATC. Of these, loss of function mutations of NF2, KMT2D, and PKHD1 were repeatedly seen in three samples (27%), two samples (18%), and two samples (18%), respectively. Using direct Sanger sequencing, two samples (18%) were also found with a RASAL1 mutation. KMT2D and RASAL1 mutations were significantly associated with shorter ATC patient survival.

CONCLUSIONS

This comprehensive analysis of ATCs using targeted massive parallel sequencing identified several novel mutations in ATCs, such as loss of function mutations of NF2 or KMT2D. Future studies are needed to confirm the role of these novel mutations as independent drivers of ATC development.

Prognostic effects of TERT promoter mutations are enhanced by coexistence with BRAF or RAS mutations and strengthen the risk prediction by the ATA or TNM staging system in differentiated thyroid cancer patients

BACKGROUND

Recent reports suggest that mutations in the promoter of the gene encoding telomerase reverse transcriptase (TERT) affect thyroid cancer outcomes.

METHODS

In all, 551 patients with differentiated thyroid cancer (DTC) enrolled in this study. The median follow-up duration was 4.8 years (interquartile range, 3.4-10.6 years).

RESULTS

TERT promoter mutations were detected in 25 DTCs (4.5%): 2.8% in neither BRAF-mutated nor RAS-mutated tumors, 4.8% in BRAF-mutated tumors, and 11.3% in RAS-mutated tumors. Moreover, they were frequently observed in American Thyroid Association (ATA) high-risk and TNM stage III/IV groups (9.1% and 12.9%, respectively). The coexistence of BRAF or RAS with TERT promoter mutations increased aggressive clinicopathologic features, recurrence (hazard ratio [HR] for BRAF, 4.64; 95% confidence interval [CI], 1.42-15.18; HR for RAS, 5.36; 95% CI, 1.20-24.02), and mortality (HR for BRAF, 15.13; 95% CI, 1.55-148.23; HR for RAS, 14.75; 95% CI, 1.30-167.00), even after adjustments for the age at diagnosis and sex, although the significance was lost after additional adjustments for pathologic characteristics. Furthermore, TERT promoter mutations significantly increased the risk of both recurrence and mortality in the ATA high-risk (HR for recurrence, 5.79; 95% CI, 2.07-16.18; HR for mortality, 16.16; 95% CI, 2.10-124.15) and TNM stage III/IV groups (HR for recurrence, 3.60; 95% CI, 1.19-10.85; HR for mortality, 9.06; 95% CI, 2.09-39.26).

CONCLUSIONS

The coexistence of BRAF or RAS mutations enhanced the prognostic effects of TERT promoter mutations. Furthermore, TERT promoter mutations strengthened the predictions of mortality and recurrence by the ATA and TNM staging systems, particularly for high-risk patients with DTC. Cancer 2016;122:1370-1379. © 2016 American Cancer Society.

Low Prevalence of Somatic TERT Promoter Mutations in Classic Papillary Thyroid Carcinoma

BACKGROUND

Transcriptional activating mutations of telomerase reverse transcriptase (TERT) are associated with more aggressive thyroid cancer. We evaluated the significance of TERT promoter mutations in Korean patients with classic papillary thyroid cancer (PTC).

METHODS

Genomic DNA was isolated from four thyroid cancer cell lines and 35 fresh-frozen PTC tissues. TERT promoter mutations (C228T and C250T) and the BRAF V600E mutation were evaluated by polymerase chain reaction amplification and direct sequencing.

RESULTS

The CC228229TT mutation in the TERT promoter was detected in BCPAP cells and the C250T mutation was found in 8505C cells. No TERT promoter mutation was observed in Cal-62 or ML-1 cells. The C228T mutation was found in only 1 of 35 (2.8%) PTCs and no C250T mutations were detected in any of the study subjects. The BRAF V600E mutation was found in 20 of 35 (57.1%) PTCs. One patient with the C228T TERT mutation also harbored the BRAF V600E mutation and developed a recurrence.

CONCLUSION

The prevalence of somatic TERT promoter mutations was low in Korean patients with classic PTC. Therefore, the prognostic role of TERT promoter mutations might be limited in this patient cohort.

Clinical utility of TERT promoter mutations and ALK rearrangement in thyroid cancer patients with a high prevalence of the BRAF V600E mutation

Background

Mutations in the TERT promoter, ALK rearrangement, and the BRAF V600E mutation are associated with aggressive clinicopathologic features in thyroid cancers. However, little is known about the impact of TERT promoter mutations and ALK rearrangement in thyroid cancer patients with a high prevalence of BRAF mutations.

Methods

We performed Sanger sequencing to detect BRAF V600E and TERT promoter mutations and both immunohistochemistry and fluorescence in situ hybridization to identify ALK rearrangement on 243 thyroid cancers.

Results

TERT promoter mutations were not present in 192 well-differentiated thyroid carcinomas (WDTC) without distant metastasis or in 9 medullary carcinomas. However, the mutations did occur in 40 % (12/30) of WDTC with distant metastasis, 29 % (2/7) of poorly differentiated carcinomas and 60 % (3/5) of anaplastic carcinomas. ALK rearrangement was not present in all thyroid cancers. The BRAF V600E mutation was more frequently found in WDTC without distant metastasis than in WDTC with distant metastasis (p = 0.007). In the cohort of WDTC with distant metastasis, patients with wild-type BRAF and TERT promoter had a significantly higher response rate after radioiodine therapy (p = 0.024), whereas the BRAF V600E mutation was significantly correlated with progressive disease (p = 0.025).

Conclusions

The TERT promoter mutation is an independent predictor for distant metastasis of WDTC, but ALK testing is not useful for clinical decision-making in Korean patients with a high prevalence of the BRAF V600E mutation. Radioiodine therapy for distant metastasis of WDTC is most effective in patients without BRAF V600E and TERT promoter mutations.

Negative Expression of CPSF2 Predicts a Poorer Clinical Outcome in Patients with Papillary Thyroid Carcinoma

BACKGROUND

The BRAF(V600E) mutation is a promising prognostic biomarker for patients with papillary thyroid carcinoma (PTC), but its prevalence differs widely among different geographic regions. A recent study reported that loss of the Cleavage and Polyadenylation Specificity Factor Subunit 2 (CPSF2) gene was associated with increased cellular invasion, cancer stem cells, and aggressiveness of PTC. This study aimed at evaluating CPSF2 protein expression as a prognostic marker for PTC in a region with a high prevalence of the BRAF(V600E) mutation, Korea.

METHODS

This study included 159 patients with classical PTC who underwent a total thyroidectomy and received ablative doses of (131)I. The expression of CPSF2 protein was evaluated by immunohistochemistry and graded semi-quantitatively. The presence of the BRAF(V600E) mutation was evaluated by direct sequencing.

RESULTS

Negative protein expression of CPSF2 was observed in 34 (21.3%) of the 159 PTCs. In multivariate analysis, negative CPSF2 expression was significantly associated with cervical lymph node metastasis (odds ratio [OR]=2.56, p=0.28), and distant metastasis (OR=3.48, p=0.02). After adjusting for age, sex, tumor size, extrathyroidal invasion, lymphovascular invasion, and the BRAF(V600E) mutation, the CPSF2-negative group had a significantly lower recurrence-free survival compared to the CPSF2-positive group (hazard ratio=2.14, p=0.03).

CONCLUSION

Negative protein expression of CPSF2 is independently associated with a poor clinical outcome in PTC. CPSF2 could be a useful prognostic marker for PTC in regions with a high prevalence of the BRAF(V600E) mutation.

Mutation Profile of Well-Differentiated Thyroid Cancer in Asians

Recent advances in molecular diagnostics have led to significant insights into the genetic basis of thyroid tumorigenesis. Among the mutations commonly seen in thyroid cancers, the vast majority are associated with the mitogen-activated protein kinase pathway. B-Raf proto-oncogene (BRAF) mutations are the most common mutations observed in papillary thyroid cancers (PTCs), followed by RET/PTC rearrangements and RAS mutations, while follicular thyroid cancers are more likely to harbor RAS mutations or PAX8/peroxisome proliferator-activated receptor γ (PPARγ) rearrangements. Beyond these more common mutations, alterations in the telomerase reverse transcriptase (TERT) promoter have recently been associated with clinicopathologic features, disease prognosis, and tumorigenesis in thyroid cancer. While the mutations underlying thyroid tumorigenesis are well known, the frequency of these mutations is strongly associated with geography, with clear differences reported between Asian and Western countries. Of particular interest is the prevalence of BRAF mutations, with Korean patients exhibiting the highest rate of BRAF-associated thyroid cancers in the world. Here, we review the prevalence of each of the most common mutations in Asian and Western countries, and identify the characteristics of well-differentiated thyroid cancer in Asians.