BRAFV600E mutation in papillary thyroid microcarcinoma: a meta-analysis

Thyroid stimulating hormone levels and BRAFV600E mutation contribute to pathophysiology of papillary thyroid carcinoma: Relation to outcomes?

AIMS

The aim of this study was to evaluate the relation between the level of thyroid stimulating hormone (TSH) and progression of papillary thyroid carcinoma (PTC) with or without BRAF^V600E mutation.

METHODS

The medical records and laboratory data of 547 patients with PTC and 94 patients with follicular adenoma (FA) were collected. The relationship between hormones levels and such end-points as extrathyroid extension (ETE), lymphovascular invasion (LVI) and lymph node metastasis (LNM) was assessed. In addition, age, gender, BRAF^V600E mutation status, histological type and Hashimoto's thyroiditis (HT) were considered.

KEY FINDINGS

Most of the patients with PTC had hormones levels within the normal range, however, serum TSH concentration was significantly higher in PTC comparing with FA (P = 0.022). High levels of TSH in PTC were more frequent among women rather than men (P = 0.03) due to the gender differences in coexisting HT rate (P = 0.003). In contrast, LNM rate was higher in men (P = 0.0014). Coexisting HT significantly decreased the risk of ETE (OR = 0.67; 95%CI 0.44-1.00; P = 0.05) and LNM (OR = 0.59; 95%CI 0.37-0.94; P = 0.028) among males with PTC. However, there was no significant relationship between HT and PTC-related ETE and LNM in females. BRAF^V600E mutation was associated with presence of lymphocytic infiltration (P < 0.001) but not with HT (P = 0.08) and violation of thyroid function.

CONCLUSION

The present study showed the lack of significant relationship between TSH levels and PTC aggressiveness (LNM, TNM stage, BRAF^V600E mutation). Higher TSH levels were found in patients with coexisting HT that was associated with female sex and multifocality of PTC.

Mutational profile of papillary thyroid microcarcinoma with extensive lymph node metastasis

PURPOSE

Papillary thyroid microcarcinoma (PTMC) has excellent outcomes, but extensive lymph node (LN) metastasis can be associated with fatal outcomes. We evaluated the mutational profiles of primary tumors and their metastatic LNs of PTMCs with extensive lateral cervical LN metastases.

METHODS

Formalin-fixed, paraffin-embedded archival samples from 16 sets of normal thyroid tissue, the primary PTMC, and the largest metastatic LN were used for targeted sequencing.

RESULTS

A total of seven somatic variants were confirmed in the PTMCs compared to the normal tissue. The BRAF^V600E mutation was the most common and seen in 12 primary tumors (75%) and 11 metastatic LNs (69%). A nonsense mutation in AR and an in-frame deletion in ACVR2A were detected in one primary tumor and its metastatic LN (6%). Missense mutations in KMT2A, RAF1, and ROS1 were detected in one primary tumor (3%). A frameshift deletion mutation in JAK2 was detected in a metastatic LN (3%). In PTMCs without the BRAF mutation, an ALK and RET rearrangement (one PTMC and its metastatic LN, 6%) was detected. In one patient, the BRAF mutation was detected in the primary tumor, but only a RET rearrangement was detected in its metastatic LN. No mutations were detected in two patients.

CONCLUSION

The mutational frequency of PTMCs was really low, even in those with extensive LN metastasis. The mutational status of the primary tumor and its metastatic LNs were not significantly different, and this suggests a minor role for genetic alterations in the process of LN metastasis in PTMC.

Understanding Pathways to the Diagnosis of Thyroid Cancer: Are There Ways We Can Reduce Over-Diagnosis?

BACKGROUND

The incidence of thyroid cancer has rapidly increased, and ecological evidence suggests this is due in some part to over-diagnosis. Understanding pathways to diagnosis could help determine whether unnecessary diagnosis can be avoided.

METHODS

A population-based sample (n = 1007) of thyroid cancer patients diagnosed between July 2013 and August 2016 was recruited from Queensland, Australia (response rate 67%). Information from structured telephone interviews was used to describe diagnostic pathways for thyroid cancer, to investigate factors associated with diagnostic pathways, and to assess the most prevalent modes of diagnoses by which the lowest-risk, potentially over-diagnosed thyroid cancers (intrathyroidal microcarcinomas) are detected.

RESULTS

Only 38% of participants presented with symptoms potentially related to thyroid cancer. Older age at diagnosis was associated with a lower prevalence of symptomatic diagnosis (prevalence ratio [PR] = 0.46 [confidence interval (CI) 0.31-0.68] for 70-79 vs. <30 years), as was frequent medical contact, while living in rural/regional areas was associated with a higher prevalence of symptomatic diagnosis (PR = 1.17 [CI 1.00-1.37] for rural/regional areas vs. major cities). Symptomatic diagnosis also occurred more for those whose tumors had adverse histopathological features (larger size, lymph node involvement, lymphovascular invasion). The likelihood of diagnosis of intrathyroidal microcarcinomas was greatest for those having surgical resection or monitoring for benign thyroid disease (PR = 3.87 [CI 2.81-5.32] and PR = 2.21 [CI 1.53-3.18], respectively).

CONCLUSIONS

A minority of newly detected thyroid cancer cases were diagnosed because of symptoms. Access to medical care and factors related to cancer aggressiveness were associated with how diagnoses occurred. The likelihood of diagnosing the lowest-risk thyroid cancers was higher in situations related to management of other thyroid conditions. Adherence to thyroid management guidelines could reduce some thyroid cancer over-diagnosis, but ultimately better diagnostic tools are needed to differentiate between indolent cancers and those of clinical significance.

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.

Thyroid Carcinoma Coexisting with Hashimoto's Thyreoiditis: Clinicopathological and Molecular Characteristics Clue up Pathogenesis

Thyroid cancer (TC) coexisting with Hashimoto’s thyroiditis (HT) presents with several characteristic features including multifocality and lower clinical stages compared to de novo carcinomas but its exact biology is still not understood. We reexamined clinico-pathological and molecular correlations between Hashimoto’s thyroditis and papillary thyroid cancer. A total of 262 patients with TC was evaluated who underwent thyroidectomy at the Surgical Department of the University of Debrecen. Clinical data, histology and molecular data were evaluated. Our cohort included 43 patients (16.4%) with (5 male, 38 female) and 219 (83.6%) patients without coexisting HT (48 male, 171 female). Hashimoto’s thyroiditis related thyroid cancer presented predominantly (93.0% of the cases) with the papillary histological type. Multifocality was observed more frequently with coexisting HT (16/40; 40.0%) compared to cases uninvolved (45/190; 23.7%)(p = 0.034). In contrast, lymphatic metastasis (pN1) with a significantly reduced frequency in patients with HT (4/11; 36.4%) then without HT (34/41 pN1; 82.9%)(p = 0.002). BRAF V600E mutation could be demonstrated at significantly lower rates in cases of PTC + HT (32.1 vs 60.7%, p < 0.005). High incidence, multifocality and papillary morphology strongly support a causal relation between TC and preexisting Hashimoto’s thyroiditis, the latter to be considered as a preneoplastic condition promoting thyroid carcinogenesis.

Precise Detection of Gene Mutations in Fine-Needle Aspiration Specimens of the Papillary Thyroid Microcarcinoma Using Next-Generation Sequencing

PURPOSE

To assess the feasibility of next-generation sequencing (NGS) to detect mutations in BRAF, RAS, TERT promoter, and TP53 genes in ultrasound-guided fine-needle aspiration (FNA) biopsy samples of the papillary thyroid microcarcinoma (PTMC).

METHODS

A total of 135 FNA samples out of 135 patients with suspected PTMC were submitted for mutation testing using NGS. NGS was successfully performed in 114 specimens, while the remaining 21 samples were excluded due to insufficient amount/poor quality of DNA and sequencing failure. Of those 114 samples, 72 who were confirmed as having PTMC by postoperative histopathology were enrolled in our study, and the other 42 who had a follow-up with ultrasound were excluded. Mutations of genes including BRAF, NRAS, HRAS, KRAS, TERT promoter, and TP53 were evaluated using NGS. The associations of gene mutations and clinicopathological characteristics of PTMC were analyzed.

RESULTS

BRAF mutation was observed in 59 (81.94%) of 72 specimens. This mutation detected in BRAF was p.V600E (c.1799T>A) in exon 15 of all 59 specimens. NRAS mutation was identified in 1 (1.39%) specimen classified as Bethesda III and pathologically confirmed as a follicular variant PTMC. There were no mutations found in TERT promoter or TP53. The tumor with a maximum diameter (D _max) larger than 5 mm was shown to be significantly correlated with the BRAF mutation in a multivariate analysis (OR 5.52, 95% CI 1.51-26.42, P = 0.033). But the BRAF mutation was not found to be significantly associated with the gender or age of patients with PTMC (P > 0.05).

CONCLUSIONS

This study demonstrated that gene mutations in FNA specimens of PTMC could be successfully analyzed with a higher sensitivity using NGS compared to conventional methods for mutation detection. BRAF mutation of p.V600E was statistically associated with PTMC with a D _max larger than 5 mm.

The BRAFV600E mutation in papillary thyroid microcarcinoma with intermediate-risk to high-risk features: does the mutation have an effect on clinical response to radioiodine therapy?

OBJECTIVES

Preclinical studies showed that BRAF mutation significantly reduced radioiodine uptake and decreased the sensitivity to radioactive iodine (RAI) therapy. However, clinical data regarding its role in therapeutic decision making with respect to RAI therapy are currently insufficient. Thus, this study aimed to evaluate the effect of BRAF mutation on the clinical response to RAI therapy for papillary thyroid microcarcinoma (PTMC) with intermediate-risk to high-risk features.

PATIENTS AND METHODS

From January 2012 and October 2015, consecutive patients with PTMC with intermediate-risk to high-risk features who underwent RAI therapy were retrospectively included. The data about BRAF mutation status were also obtained. The association between clinicopathological characteristics and mutation was investigated. After a median follow-up of 40 months, the clinical response to RAI therapy was also compared between positive and negative mutation groups.

RESULTS

A total of 236 patients were included, of whom 147 (62.3%) had positive mutation. The clinicopathological features did not show significant correlation with BRAF mutation status except the sex, extrathytoidal extension and T stage. Patients with PTMC with BRAF mutation showed an increased likelihood of having advanced T stage and extrathyroidal extension. In addition, this mutation did not affect the clinical outcome of RAI therapy.

CONCLUSION

The status of BRAF mutation may not affect the clinical response to RAI therapy for patients with PTMC with intermediate-risk to high-risk features. More trials examining the role of BRAF mutation in guiding postoperative RAI therapy are needed.

Surgical Treatment in Papillary Thyroid Microcarcinoma

Despite the notable increasing incidence of papillary thyroid microcarcinoma (PTMC), the optimal treatment of the patients with PTMC remains controversial. Because of no consensus about its treatment, the suggested treatment varies from active surveillance alone to total thyroidectomy. Although the 2015 revised American Thyroid Association guideline recommends hemithyroidectomy as the first-line treatment, active surveillance has also been discussed and accepted as another approach for the patients with PTMC. However, the same guideline does not recommend fine needle aspiration biopsy for nodules sized <1 cm, even it is suspicious. In such situation, neither active surveillance nor hemithyroidectomy could be discussed, with a lack of objective cytologic data about the nodules sized <1 cm. In this situation, the decision to perform FNAB to the nodules <1 cm in size depends on the performer of the thyroid ultrasonography. In this invited review, we have discussed the diagnosis and prognostic factors for PTMCs. We have also discussed surgical strategies as the accepted the first-line treatment in patients with PTMC.

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.

Cell adhesion-related gene somatic mutations are enriched in aggressive papillary thyroid microcarcinomas

Background

Approximately half of the documented increases in differentiated thyroid carcinoma is due to identification of papillary thyroid microcarcinomas (PTMCs). Knowing whether PTMC is aggressive is required for proper treatment, but until now, there has been no method for assessing these traits and understanding the underlying mechanisms for aggressiveness.

Methods

We performed whole-exome sequencing of 16 PTMCs and matched normal thyroid tissues and GO/KEGG analysis to study genetic alterations and biological consequences associated with aggressive PTMCs, and then sequenced these genes using a next-generation gene-panel approach in an additional 70 PTMC samples including aggressive (n = 50) and non-aggressive (n = 20) groups.

Results

We identified 254 somatic mutations of 234 genes, for which 178 mutations in 168 genes were found in the aggressive group, and 76 mutations in 74 genes were found in the non-aggressive group. Several recurrent mutations in BRAF, VCAN, ALDH1L1, and MUC5B were identified, and many novel but infrequent mutations in other genes were also found. The aggressive cohort had more mutational burdens than the non-aggressive group (P = 0.004). Nonsynonymous mutations of 13 genes (MUC5B, TNN, SSPO, PPFIA1, PCDHGA2, ITGA8, ITGA4, DCHS1, CRNN, ROCK1, RELN, LAMC2, and AEBP1) were involved in cell adhesion, and these were only present in the aggressive group. Targeted sequencing of these genes revealed significant enrichment in the aggressive group (P = 0.000004).

Conclusion

PTC may have evolved from PTMC due to sharing similar gene mutations, and the accumulation of such mutations promoted the aggressiveness of PTMC. Gene mutants associated with cell adhesion may be used to predict PTMC aggressiveness and allow more selective treatment.

BRAF V600E and RET/PTC Promote the Activity of Nuclear Factor-κB, Inflammatory Mediators, and Lymph Node Metastasis in Papillary Thyroid Carcinoma: A Study of 50 Patients in Inner Mongolia

BACKGROUND The aim of this study was to investigate the expression of the BRAF V600E gene mutation and the RET/PTC gene rearrangement in the progression of papillary thyroid carcinoma (PTC) in 50 patients from Inner Mongolia. MATERIAL AND METHODS Clinical data, blood, and tissue samples were obtained from 50 patients with PTC and ten patients with benign thyroid adenoma. Expression of BRAF V600E, RET/PTC, nuclear factor-κB (NF-κB), interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, C-X-C motif chemokine ligand (CXCL)1, CXCL2, C-C motif chemokine ligand (CCL)2, and CCL3 were measured using polymerase chain reaction (PCR), immunohistochemistry, and an enzyme-linked immunosorbent assay (ELISA). RESULTS Of the 50 patients with PTC, 37 patients expressed the BRAF V600E gene mutation, eight patients expressed RET/PTC, and five patients showed concomitant BRAF V600E and RET/PTC. Time to recurrence for patients with PTC with BRAF V600E was significantly increased compared with patients with concomitant BRAF V600E mutation and RET/PTC rearrangement (P<0.05). Expression of BRAF V600E, RET/PTC, and concomitant expression of BRAF V600E and RET/PTC were significantly associated with patient age and lymph node metastasis (P<0.05). Serum levels of NF-κB, IL-1β, IL-6, TNF-α, TGF-β and CCL3, and tumor tissue levels of IL-1β, IL-6, TNF-α, TGF-β, CXCL2 and CCL2 in patients with PTC were significantly increased compared with patients with benign thyroid adenoma, before and after surgery (P<0.05). CONCLUSIONS Expression of the BRAF V600E mutation and RET/PTC translocation promoted the activity of NF-κB, expression of inflammatory mediators, and lymph node metastases in patients with PTC.

BRAFV600E Mutation Does Not Significantly Affect the Efficacy of Radioiodine Therapy in Patients With Papillary Thyroid Carcinoma Without Known Distant Metastases

PURPOSE

The BRAF mutation is the most common and specific oncogenic event in papillary thyroid carcinoma (PTC). However, its role in radioiodine therapy decision making has yet to be established. This study aimed to evaluate the impact of the BRAF mutation on the clinical response to radioiodine therapy.

METHODS

This retrospective study included PTC patients who received total thyroidectomy with lymph node dissection, radioiodine therapy, and thyroid-stimulating hormone suppression between January 2012 and March 2016. Included patients were divided into 2 groups based on the BRAF mutation status. The association between the clinicopathological characteristics and the BRAF mutation was evaluated. After a median follow-up of 37 months, the clinical outcome between these 2 groups was also compared based on the ongoing risk stratification.

RESULTS

A total of 512 PTC patients without distant metastases were included, with a positive BRAF mutation in 338 patients. No significant association was observed between the BRAF mutation and clinicopathological characteristics, except for sex, tumor size, and extrathyroidal extension. The initial risk stratification between the positive and negative mutation groups revealed no significant difference (P = 0.845). At the end of follow-up, no significant difference regarding the clinical response to radioiodine therapy was demonstrated between these 2 groups for all patients or patients with high recurrence risk (P = 0.586 and P = 0.680, respectively).

CONCLUSIONS

The BRAF mutation status may not impact the clinical response to radioiodine therapy for PTC patients without distant metastases.

Profile and clinical implication of circular RNAs in human papillary thyroid carcinoma

Background

Differently expressed circular RNAs (circRNAs) have been reported to play a considerable role in tumor behavior; however, the expression profile and biological function of circRNAs in papillary thyroid carcinoma (PTC) remains unknown. Thus, the study was aimed to characterize the circRNA expression profile to comprehensively understand the biological behavior of PTC.

Methods

We investigated the expression profile of circRNAs using circRNA microarray in three pairs of PTC and adjacent normal tissues. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to validate eight candidate circRNAs in 40 paired PTC tumors and adjacent normal samples. Next, we employed a bioinformatics tool to identify putative miRNA and circRNA-associated downstream genes, followed by constructing a network map of circRNA-miRNA-mRNA interactions and exploring the potential role of the candidate circRNAs.

Results

In total, 206 up- and 177 downregulated circRNAs were identified in PTC tissues (fold change >1.5; P < 0.05). The expression levels of eight candidate circRNAs confirmed by qRT-PCR were significantly different between the PTC and normal samples. The downstream genes of candidate circRNAs participated in various biological processes and signaling pathways. The most up and downregulated circRNAs were hsa_circRNA_007148 and hsa_circRNA_047771. The lower expression level of hsa_circRNA_047771 was associated BRAFV600 mutation, lymph node metastasis (LNM), as well as with advanced TNM stage (all P < 0.05). The higher expression level of hsa_circRNA_007148 was significantly correlated with LNM (P < 0.05). The areas under receiver operating curve were 0.876 (95% CI [0.78-0.94]) for hsa_circRNA_047771 and 0.846 (95% CI [0.75-0.96]) for hsa_circRNA_007148.

Discussion

The study suggests that dysregulated circRNAs play a critical role in PTC pathogenesis. PTC-related hsa_circRNA_047771 and hsa_circRNA_007148 may serve as potential diagnostic biomarkers and prognostic predictors for PTC patients.

Decision making processes of women who seek elective oocyte cryopreservation

PURPOSE

The aim of this study is to analyze women's opinions and their decision making processes regarding elective oocyte cryopreservation (OC).

METHODS

One hundred twenty-four women who had elective OC counseling at the CHA Seoul Fertility Center were asked to complete a survey after their first visit. Data collection regarding age, marital status, monthly income, occupation, religion, reproductive history, questions about the participant's view on their own fecundity, and future parenthood were included. The modified Reproductive Concerns After Cancer scale and the Decisional Conflict Scale were used for analysis.

RESULTS

The participants' mean age was 37.1 ± 4.8 years old. Eighty-six percent of the participants had regular periods. Ninety-two percent thought it was important to have their own biological offspring, and 86% were willing to pursue OC. Forty-nine percent appeared to have high DCS scores regarding making a decision of OC. Sixty-eight percent pursued OC, and the mean number of oocytes cryopreserved per patient was 10.5 ± 8.3. Multivariate analysis revealed that age was the only factor associated with high DCS scores (P = 0.002). Feeling less fertile than other women of same age and low DCS scores were the factors associated with pursuing OC (P = 0.02 and 0.004, respectively) after adjusting for possible confounding factors, including age.

CONCLUSIONS

Older women had more difficulties in making decisions about OC. Adjusting for age, women who thought that they were less fertile than other women of same age and those with lower decisional conflict were more likely to pursue OC. Further studies should focus on the validation of older women's decisional conflicts regarding OC.

Association between diffuse lymphocytic infiltration and papillary thyroid cancer aggressiveness according to the presence of thyroid peroxidase antibody and BRAFV600E mutation

BACKGROUND

Diffuse lymphocytic infiltration (DLI) is frequently found with papillary thyroid cancer (PTC), so there has been long interest in how it affects the characteristics of PTC. This purpose of this study was to define the association between DLI and PTC aggressiveness according to thyroperoxidase antibody (TPOAb) and B-type Raf (BRAF)^V600E mutation positivity.

METHODS

There were 1879 patients with PTC who underwent surgery and were enrolled in this study. Clinicopathologic characteristics were compared between groups according to the presence of DLI and TPOAb. Multiple logistic regression analysis was conducted to assess odds ratio (OR) for each dependent variable (BRAF^V600E mutation, tumor size >1.0 cm, multifocality, extrathyroidal extension, and lymph node metastasis) of each group according to the presence of DLI and TPOAb, with the group with neither DLI or TPOAb (DLI-negative TPOAb-negative PTC) as the reference.

RESULTS

The DLI-positive PTC showed more frequent multifocality and less frequent BRAF^V600E mutation than DLI-negative PTC. Among patients with DLI-positive PTC, extrathyroidal extension and BRAF^V600E mutation was less frequent when serum TPOAb was positive. In multiple logistic regressions, DLI-positive TPOAb-positive PTC showed a high OR for multifocality (1.410; P = .017), but low ORs for BRAF^V600E mutation (0.521; P < .001) and extrathyroidal extension (0.691; P = .008). The patients with DLI-positive TPOAb-positive PTCs showed a high OR for multifocality (1.588; P = .002), and high ORs for tumor size >1.0 cm (2.205; P = .019) and lymph node metastasis (2.005; P = .032) in subgroup analyses of PTC with wild-type BRAF. The DLI-negative TPOAb-positive group was not associated with any tumor aggressiveness-related variables.

CONCLUSION

Although DLI was associated with multifocality regardless of TPOAb positivity, it was associated with an indolent feature when TPOAb was positive but with aggressive features in PTC with wild-type BRAF when TPOAb was negative. The TPOAb and BRAF status may help to define the clinical implication of lymphocytic infiltration found with PTC.

Targeted next generation sequencing identifies somatic mutations and gene fusions in papillary thyroid carcinoma

138 papillary thyroid carcinoma (PTC) samples were assessed for somatic mutation profile and fusion genes by targeted resequencing using a cancer panel (ThyGenCap^TM) targeting 244 cancer-related genes and 20 potential fusion genes. At least one genetic alteration (including mutations and fusion genes) was observed in 118/138 (85.5%) samples. The most frequently mutated gene was BRAF V600E (57.2%). Moreover, we identified 11 fusion genes including eight previously reported ones and three novel fusion genes, UEVLD-RET, OSBPL9-BRAF, and SQSTM1-NTRK3. Alterations affecting the mitogen-activated protein kinase (MAPK) signaling pathway components were seen in 69.6% of the PTC cases and all of these driver mutations were mutually exclusive. Univariate analysis ascertained that the fusion genes were strongly associated with distinct clinicopathological characteristics, such as young age, local invasion, extensive metastasis, and disease stage. In conclusion, our approach facilitated simultaneous high-throughput detection of gene fusions and somatic mutations in PTC samples.

Molecular markers in well-differentiated thyroid cancer

PURPOSE

Thyroid nodules are of common occurrence in the general population. About a fourth of these nodules are indeterminate on aspiration cytology placing many a patient at risk of unwanted surgery. The purpose of this review is to discuss various molecular markers described to date and place their role in proper perspective. This review covers the fundamental role of the signaling pathways and genetic changes involved in thyroid carcinogenesis. The current literature on the prognostic significance of these markers is also described.

METHODS

PubMed was used to search relevant articles. The key terms "thyroid nodules", "thyroid cancer papillary", "carcinoma papillary follicular", "carcinoma papillary", "adenocarcinoma follicular" were searched in MeSH, and "molecular markers", "molecular testing", mutation, BRAF, RAS, RET/PTC, PAX 8, miRNA, NIFTP in title and abstract fields. Multiple combinations were done and a group of experts in the subject from the International Head and Neck Scientific Group extracted the relevant articles and formulated the review.

RESULTS

There has been considerable progress in the understanding of thyroid carcinogenesis and the emergence of numerous molecular markers in the recent years with potential to be used in the diagnostic algorithm of these nodules. However, their precise role in routine clinical practice continues to be a contentious issue. Majority of the studies in this context are retrospective and impact of these mutations is not independent of other prognostic factors making the interpretation difficult.

CONCLUSION

The prevalence of these mutations in thyroid nodule is high and it is a continuously evolving field. Clinicians should stay informed as recommendation on the use of these markers is expected to evolve.

BRAF V600E Mutation-Assisted Risk Stratification of Solitary Intrathyroidal Papillary Thyroid Cancer for Precision Treatment

Background

Precise risk stratification-based treatment of solitary intrathyroidal papillary thyroid cancer (SI-PTC) that is larger than 1.0 cm and 4.0 cm or less is undefined.

Methods

A genetic-clinical risk study was performed on BRAF V600E in 955 patients (768 women and 187 men) with SI-PTC, with median age of 46 years and median clinical follow-up time of 64 months at 11 medical centers in six countries. The chi-square test or, for analyses with small numbers, Fisher's exact test was performed to compare recurrence rates. Recurrence-free probability was estimated by Kaplan-Meier (KM) analysis, and the independent effect of BRAF mutation on the recurrence was analyzed by Cox regression and Cox proportional hazard analyses. All statistical tests were two-sided.

Results

Recurrence of SI-PTC larger than 1.0 cm and 4.0 cm or less was 9.5% (21/221) vs 3.4% (11/319) in BRAF mutation vs wild-type BRAF patients, with a hazard ratio (HR) of 3.03 (95% confidence interval [CI] = 1.46 to 6.30) and a patient age- and sex-adjusted hazard ratio of 3.10 (95% CI = 1.49 to 6.45, P = .002). Recurrence rates of SI-PTC larger than 2.0 cm and 4.0 cm or less were 16.5% (13/79) vs 3.6% (5/139) in mutation vs wild-type patients (HR = 5.44, 95% CI = 1.93 to 15.34; and adjusted HR = 5.58, 95% CI = 1.96 to 15.85, P = .001). Recurrence rates of SI-PTC larger than 3.0 cm and 4 cm or less were 30.0% (6/20) vs 1.9% (1/54) in mutation vs wild-type patients (HR = 18.40, 95% CI = 2.21 to 152.98; and adjusted HR = 14.73, 95% CI = 1.74 to 124.80, P = .01). Recurrences of mutation-positive SI-PTC were comparable with those of counterpart invasive solitary PTC, around 20% to 30%, in tumors larger than 2.0 cm to 3.0 cm. BRAF mutation was associated with a statistically significant decrease in recurrence-free patient survival on KM analysis, particularly in SI-PTC larger than 2.0 cm and 4.0 cm or less. Similar results were obtained in conventional SI-PTC. The negative predictive values of BRAF mutation for recurrence were 97.8% (95% CI = 96.3% to 98.8%) for general SI-PTC and 98.2% (95% CI = 96.3% to 99.3%) for conventional SI-PTC.

Conclusions

BRAF V600E identifies a subgroup of SI-PTC larger than 1.0 cm and 4.0 cm or less, particularly tumors larger than 2.0 cm and 4.0 cm or less, that has high risk for recurrence comparable with that of invasive solitary PTC, making more aggressive treatment reasonable.

Thyroid functional parameters and correlative autoantibodies as prognostic factors for differentiated thyroid cancers

To evaluate the effect of preoperative thyroid functional parameters and thyroid autoantibodies on aggressive clinicopathologic features and lymph node metastasis (LNM) of differentiated thyroid cancer patients. Four hundred twenty consecutive patients with initial surgery were enrolled from July 2010 to July 2015. The associations between aggressive clinicopathologic and LNM factors and thyroid functional & autoantibodies parameters were analyzed. Higher levels of TSH, TGAb or TMAb were found in patients with tumor size≥1 cm (all P<0.05), especially when TSH≥2.5 ulU/ml (P=0.03) and TGAb≥1 (P=0.01). Higher levels of TSH and TGAb and lower levels of T3 and T4 were found in patients with capsular invasion (all P<0.05), particularly when TSH≥2.5ulU/ml (P=0.03) and TGAb≥1 (P=0.005). The patients with multifocality had higher TAbs level (TAbs>1). Higher level of TSH was also found in patients with central LNM (P=0.001) and lateral LNM (P=0.002), especially with TSH≥2.5ulU/ml (P=0.003 and P=0.03). TGAb level was also found higher in patients with central LNM (P=0.02) and lateral LNM (P=0.01), especially with TGAb≥1 (P<0.05 and P=0.01). Higher level of TMAb was found in patients with lateral LNM (P<0.05). Moreover, multivariable analysis revealed that only TGAb was an independently predictive factor for primary tumor size≥1cm (P=0.01); and TSH level (P=0.01) and TGAb≥1 (P<0.05) were associated independently with central LNM. Thus, TSH level and TGAb≥1 were significantly independent predictors for central LNM, and might help make the decision of central neck dissection.

Thyroid Cancer: Risk-Stratified Management and Individualized Therapy

Thyroid cancer is the most common endocrine malignancy. Differentiated thyroid cancer (DTC) with the two subtypes, papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC), is the most frequent subtype of thyroid cancer; more rare subtypes are medullary thyroid cancer (MTC) and anaplastic thyroid cancer (ATC). The incidence of DTC has increased rapidly in recent years due to the more frequent use of imaging methods such as ultrasound of the neck and fine-needle aspiration (FNA) of thyroid nodules. After total thyroidectomy and radioiodine treatment, DTC remains an indolent and curable disease in most patients, whereas the cure rate in MTC is lower and depends on early diagnosis. Most ATCs are incurable. In recent years, there has been great progress in identifying genetic changes in thyroid cancer, and genetic testing of FNA samples or blood samples provides useful information for clinical decision making. Tumor staging, either postoperatively or by imaging, and measuring the tumor markers thyroglobulin for DTC and calcitonin for MTC, allow for dynamic risk-adapted stratification for follow-up procedures. In advanced metastatic thyroid cancer, molecular targeted therapy using tyrosine kinase receptor inhibitors, including sorafenib, lenvantinib, vandetanib, and cabozantinib, helps control tumor progression and prolongs progression-free survival. Using a dynamic risk-stratified approach to manage thyroid cancer, the outcomes for most thyroid cancer patients are excellent compared with those for other cancers. The major challenge in the future is to identify high-risk patients and to treat and monitor them appropriately. Clin Cancer Res; 22(20); 5012-21. ©2016 AACR SEE ALL ARTICLES IN THIS CCR FOCUS SECTION, "ENDOCRINE CANCERS REVISING PARADIGMS".

Diagnostic significance of CK19, galectin-3, CD56, TPO and Ki67 expression and BRAF mutation in papillary thyroid carcinoma

The aim of the present study was to examine the rate of BRAF mutation and the expression profiles of CK19, galectin-3, CD56, thyroid peroxidase (TPO) and Ki67 in papillary thyroid carcinoma (PTC) and papillary thyroid micro-carcinoma (PTMC). A total of 246 cases of thyroid disease were collected, including PTC, PTMC, nodular goiter (NG) and Hashimoto thyroiditis (HT). The results revealed that CK19 expression was 116/120 in PTC, 61/64 in PTMC, 2/34 in NG and 1/28 in HT. Galectin-3 positive expression was 115/120 in PTC, 60/64 in PTMC, 6/34 in NG and 4/28 in HT. TPO positive expression was 8/120 in PTC, 1/64 in PTMC, 30/34 in NG and 25/28 in HT. CD56-positive expression was 12/120 in PTC, 3/64 in PTMC, 33/34 in NG and 26/28 in HT. Ki67 labeling index was 2.52±0.46% in PTC (120 cases), 2.62±0.52% in PTMC (64 cases), 2.55±0.44% in NG (34 cases) and 2.58±0.48% in HT (28 cases). BRAF mutation rate was 93/120 in PTC, 47/64 in PTMC, 3/34 in NG and 2/28 in HT. These results suggested that expression patterns of CK19, galectin-3, CD56 and TPO and BRAF mutation exhibit diagnosis value in thyroid disease. However, Ki67-positive rate exhibits no notable diagnosis value in thyroid disease.

[Surgery of papillary thyroid microcarcinoma]

BACKGROUND

Different countries are currently reporting a substantial increase in the incidence rates of papillary thyroid microcarcinoma (PTMC).

OBJECTIVE

Presentation of diagnosis and surgical therapy of PTMC and discussion of a more conservative approach, such as active surveillance.

MATERIAL AND METHODS

Overview of the current guidelines from different countries and analysis of recent publications reporting the results of active surveillance of PTMC from Japan, Korea and the USA.

RESULTS

The majority of international guidelines for PTMC recommends thyroid lobectomy as the gold standard. Active surveillance as an alternative procedure is described in the Japanese guidelines (JSTS/JAES). Present surveillance studies including more than 1700 patients report a tumor growth in 8-14% of the cases during a median follow-up of up to 75 months. Tumor growth and lymph node metastases are detected most frequently in younger patients (below 40-50 years).

CONCLUSION

Active surveillance might serve as an alternative treatment option for older patients with PTMC. Since the median follow-up periods are currently not long enough, it seems difficult to draw definite conclusions of this procedure right now.

Active Surveillance for Papillary Thyroid Microcarcinoma: Challenges and Prospects

Active surveillance (AS) can be considered as an alternative to immediate surgery in low-risk papillary thyroid microcarcinoma (PTMC) without clinically apparent lymph nodes, gross extrathyroidal extension (ETE), and/or distant metastasis according to American Thyroid Association. However, in the past AS has been controversial, as evidence supporting AS in the management of PTMC was scarce. The most prominent of these controversies included, the limited accuracy and utility of ultrasound (US) in the detection of ETE, malignant lymph node involvement or the advent of novel lymph node malignancy during AS, and disease progression. We summarized publications and indicated: (1) US, performer-dependent, could not accurately diagnose gross ETE or malignant lymph node involvement in PTMC. However, the combination of computed tomography and US provided more accurate diagnostic performance, especially in terms of selection sensitivity. (2) Compared to immediate surgery patients, low-risk PTMC patients had a slightly higher rate of lymph node metastases (LNM), although the overall rate for both groups remained low. (3) Recent advances in the sensitivity and specificity of imaging and incorporation of diagnostic biomarkers have significantly improved confidence in the ability to differentiate indolent vs. aggressive PTMCs. Our paper reviewed current imagings and biomarkers with initial promise to help select AS candidates more safely and effectively. These challenges and prospects are important areas for future research to promote AS in PTMC.

BRAF 1799T>A Mutation Frequency in Mexican Mestizo Patients with Papillary Thyroid Cancer

Thyroid cancer is the most frequent endocrine malignancy, and its incidence and prevalence are increasing worldwide. Despite its generally good prognosis, the observed mortality rates are higher in the less-developed regions. This indicates that timely diagnosis and appropriate initial management of this disease are important to achieve a positive outcome. We performed an observational study in order to describe the frequency of the BRAF 1799T>A mutation in Mexican mestizo patients with thyroid nodules, a scarcely studied ethnic group with large populations. Competitive allele-specific Taqman PCR was performed in 147 samples of thyroid tissue DNA obtained from patients histologically diagnosed with papillary thyroid cancer (PTC), colloid goiters, and follicular adenomas. The BRAF 1799T>A mutation frequency was 61.1% in PTC samples (p = 4.99 × 10⁻¹¹). Potential diagnostic values were as follows: sensitivity, 61.1%; specificity, 96%; PPV, 94.2%; NPV, 69.5%; accuracy, 77.9%. Taking into account the fact that this mutation is not frequently found in cytologically indeterminate nodules, we suggest that the BRAF mutational analysis should be implemented in the clinical setting along with other diagnostic criteria such as USG, in order to contribute to diagnosis and to surgical decision-making during the initial management of thyroid nodules in Mexican public hospitals.

Immunohistochemistry cannot replace DNA analysis for evaluation of BRAF V600E mutations in papillary thyroid carcinoma

INTRODUCTION

The BRAF V600E mutation is the most common genetic event occurring in papillary thyroid cancer (PTC). Recently, the possibility of using immunohistochemistry (IHC) to detect the BRAF V600E mutation has been reported.

MATERIALS AND METHODS

In 140 patients with classical PTC, the status of the BRAF V600E mutation was determined by IHC (using two alternative staining protocols, IHC-1 and IHC-2) and molecular biology methods: Sanger sequencing (SEQ) and real-time PCR (qPCR).

RESULTS

The BRAF V600E mutation was detected in 57.1% (80/140) patients by IHC-1 and 62.9% (88/140) patients by IHC-2. The highest correlation in detecting the BRAF V600E mutation was found between IHC-2 and qPCR (94.2%), and between IHC-1 and qPCR (83.9%). Correlations between IHC-1 and SEQ and between IHC-2 and SEQ were 71.5% and 76.2%, respectively. The IHC-2 protocol had higher sensitivity, PPV, and NPV, and Cohen's kappa than IHC- 1. The presence of BRAF V600E mutation in IHC-2 statistically correlated with age at diagnosis, histopathological stage, and extrathyroidal extension.

CONCLUSIONS

The results obtained in this study indicate a lack of concordance between BRAF V600E detection by IHC and molecular methods. The IHC method cannot replace molecular methods for the detection of the BRAF V600E mutation.

Aggressiveness of the tall cell variant of papillary thyroid carcinoma is independent of the tumor size and patient age

The tall cell variant (TCV) of papillary thyroid carcinoma (PTC) is characterized by tall columnar cells with a height of at least three times their width. TCV usually presents at an older age, has a larger size and exhibits more extrathyroidal extension and metastases than classical PTC. The current study compared TCV with the classical and follicular variants (CaFVs) of PTC to determine if, irrespective of the age at diagnosis and tumor size, TCV is more aggressive than its classical and follicular counterparts. A total of 16 (3.66%) patients with TCV were identified in a series of 437 patients with PTC from the Clinical University Hospital (Santiago de Compostela, Spain) between 1990 and 2010. The patient clinicopathological features and B-Raf proto-oncogene (BRAF)V600E mutational status were compared with 34 cases of CaFVs of PTC matched for tumor size and patient age. The TCV series included 11 females and 5 males aged 15–74 years (median, 57 years). In total, 15 (93.8%) patients underwent total or near-total thyroidectomy, 1 underwent lobectomy and 5 (31.3%) underwent lymph node dissection. In the TCV series, the tumor size ranged from 5–45 mm (median, 19 mm). Compared with the CaFVs, the TCV of PTC exhibited a significantly higher prevalence of extrathyroidal extension [9/16 (56.3%) vs. 5/34 (14.7%) cases; P=0.007], lymph node metastases [9/16 (56.3%) vs. 9/34 (26.4%) cases; P=0.04], stage III/IV at presentation [10/16 (62.5%) vs. 7/34 (20.5%) cases; P=0.009] and BRAFV600E mutation [12/16 (80.0%) vs. 7/25 (28.0%) cases; P=0.004]. The TCV series also harbored more multifocal papillary carcinomas (50.0% vs. 26.4%), lymphovascular invasion (37.5% vs. 29.4%) and distant metastases (6.2% vs. 0.0%), as compared with the matched patient cohort. In conclusion, the TCV of PTC is frequently associated with BRAFV600E mutation and is more aggressive than the CaFVs of PTC, regardless of tumor size and patient age at diagnosis.

Oncogenic BRAF disrupts thyroid morphogenesis and function via twist expression

Thyroid cancer is common, yet the sequence of alterations that promote tumor formation are incompletely understood. Here, we describe a novel model of thyroid carcinoma in zebrafish that reveals temporal changes due to BRAFV600E. Through the use of real-time in vivo imaging, we observe disruption in thyroid follicle structure that occurs early in thyroid development. Combinatorial treatment using BRAF and MEK inhibitors reversed the developmental effects induced by BRAFV600E. Adult zebrafish expressing BRAFV600E in thyrocytes developed invasive carcinoma. We identified a gene expression signature from zebrafish thyroid cancer that is predictive of disease-free survival in patients with papillary thyroid cancer. Gene expression studies nominated TWIST2 as a key effector downstream of BRAF. Using CRISPR/Cas9 to genetically inactivate a TWIST2 orthologue, we suppressed the effects of BRAFV600E and restored thyroid morphology and hormone synthesis. These data suggest that expression of TWIST2 plays a role in an early step of BRAFV600E-mediated transformation.

Correlation of BRAF mutation and SUVmax levels in thyroid cancer patients incidentally detected in 18F-fluorodeoxyglucose positron emission tomography

The prognostic importance of ¹⁸F-fluorodeoxyglucose avidity in primary thyroid tumor and molecular basis responsible for its mechanism has not yet been well characterized. In this study, we aimed to evaluate the correlation between the maximum standardized uptake levels and B-type Raf kinase mutation positivity in incidentally detected papillary thyroid cancer patients during ¹⁸F-fluorodeoxyglucose positron emission tomography examination. We retrospectively evaluated 6873 ¹⁸F-fluorodeoxyglucose-positron emission tomography scans of consecutive subjects from a database search for tumor staging in 2014 at our hospital Nuclear Medicine Center. In total, 135 patients had focal ¹⁸F-fluorodeoxyglucose uptake in the thyroid. Of these, 76 patients had fine-needle aspiration biopsy. ¹⁸F-fluorodeoxyglucose-maximum standardized uptake of the positron emission tomography-detected nodules was recorded. B-type Raf kinase (V600E) mutation and p53 protein expression were evaluated in papillary thyroid cancer patients. The incidence of thyroid incidentaloma in ¹⁸F-fluorodeoxyglucose-maximum standardized uptake scans was 2 % (135/6873). Of the 76 patients evaluated, 41 % (n = 31) were diagnosed papillary thyroid cancer. B-type Raf kinase mutation was positive in 51 % (17/30) of the papillary thyroid cancer patients. Maximum standardized uptake levels of the nodules (≥1 cm) were significantly higher in B-type Raf kinase-mutated papillary thyroid cancer patients than in non-mutated patients [16.6 (10.4-27.9) vs. 9.7 (6.8-11.1); P = 0.007]. Correlation analysis revealed that maximum standardized uptake was significantly associated with B-type Raf kinase mutation positivity (r = 0.519; P = 0.005). Logistic regression analysis showed an association between maximum standardized uptake and B-type Raf kinase mutation positivity even after adjustment for age and gender (P = 0.01). B-type Raf kinase mutation is closely related to ¹⁸F-fluorodeoxyglucose-positron emission tomography maximum standardized uptake levels in patients with incidentally detected papillary thyroid cancer.

The micropapillary/hobnail variant of papillary thyroid carcinoma: A review of series described in the literature compared to a series from one southern Italy pathology institution

Papillary thyroid carcinoma (PTC) has a good prognosis with a 10-yr survival greater than 90%. Recently, a micro-papillary pattern with hobnail appearance (MPHC) in PTC has been indicated as associated with poor prognosis, but this suggestion is based only on a few cases from geographical areas different from ours. Two-hundred ninety-nine consecutive PTC cases were collected between the years of 1992 and 2014 at our institution. The corresponding histologic sections (at least 6 for each case) were stained with hematoxylin and eosin and reviewed independently by two pathologists to reach a consensus on the identification and quantification of the MPHC. As done in other cohorts, parallel serial sections were stained with antisera for thyroglobulin, epithelial membrane antigen, thyroid-transcription-factor-1 and Ki 67. BRAF gene mutation at codon 600 and RET/PTC1 gene rearrangements were searched. A comparative statistical analysis was done between the present series and previously published series. Of the 295 PTC, 124 (42.5%) were follicular, 104 (35%) classic, 34 (11.5%) sclerosing, 15 (5%) tall cells, 10 (3.4%) Warthin-like, and 8 (2.7%) MPHC. Four MHPC cases (50%) harbored the BRAF V600E variant, while one was positive for RET/PTC1 rearrangement. Our rate of MPHC-PTC (2.7%) is 2X to 8X greater than those reported previously for cohorts from North America + North Italy, Korea and Mexico. MPHC prognosis appears to be better compared to other cohorts, probably due to not only to the lower rate of the vascular invasion, but also to the smaller size of the MPHC-PTC nodule.

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.

Papillary thyroid microcarcinoma: time to shift from surgery to active surveillance?

The incidence of differentiated thyroid cancer is increasing greatly in high-income countries. Roughly 50% of this increase is attributable to the identification of intrathyroidal papillary thyroid microcarcinomas. Since mortality associated with these tumours remains low and stable, the increasing diagnosis has led to concerns about overdiagnosis and overtreatment. Management of papillary thyroid microcarcinomas should take into account the reported absence of mortality when diagnosed in the absence of lymph node metastases and distant metastases, as shown even in recent studies promoting active surveillance; a low recurrence rate of 1-5%; and the risk of permanent complications from surgery that cannot be decreased to less than 1-3%, even in high-volume tertiary care centres with experienced surgeons. On the basis of these data, active surveillance with curative intent, in which active treatment is delayed until the cancer shows signs of significant progression to avoid side-effects of treatment, should be considered in properly selected patients.

Is papillary thyroid microcarcinoma an indolent tumor?: A retrospective study on 280 cases treated with radioiodine

The increasing detection of papillary thyroid microcarcinoma (PTMC) has created management dilemmas. To clarify the clinical significance of postsurgery stimulated thyroglobulin (ps-Tg) in PTMC who undergo thyroidectomy and radioactive iodine (RAI), we retrospectively reviewed the 358 PTMC patients who were treated with RAI and followed up in our hospital. Those with an excessive anti-Tg antibody, ultrasound-detected residual were excluded, thereby resulting in the inclusion of 280 cases. Their clinical and histopathological information and clinical outcomes were collected and summarized. Tumor stages were classified according to the tumor, node, metastasis (TNM) staging system and the consensus of the European Thyroid Association (ETA) risk stratification system, respectively. Kaplan-Meier curves were constructed to compare the disease-free survival (DFS) rates of different risk-staging systems. By the end of follow-up, none of the patients died of the disease or relapsed. The 8-year DFS rate was 76.9%. Kaplan-Meier curves showed different DFS rates in TNM stages I versus IV, III versus IV, very low risk versus high risk, low risk versus high risk, respectively (P < 0.05), while they were not significantly different in stage I versus stage III, very low risk versus low risk (P > 0.05). Finally, 40 (14.3%) cases got a persistent disease. Five variables (male sex, nonconcurrent benign pathology, initial tumor size >5 mm, lymph node metastasis, and ps-Tg ≥ 10 μg/L) were associated with disease persistence by univariate regression analysis. Ps-Tg ≥ 10 μg/L was the only independent prognostic variable that predicted disease persistence by multivariate regression analysis (odds ratio: 36.057, P = 0.000). Therefore, PTMC with a small size of ≤1 cm does not always act as an indolent tumor. In conclusion, ps-Tg ≥ 10 μg/L is associated with increased odds of disease persistence. ETA risk stratification is more effective in predicting disease persistence than the TNM classification system.

Reappraisal of the indication for radioiodine thyroid ablation in differentiated thyroid cancer patients

Radioactive iodine therapy is administered to patients with differentiated thyroid cancer (DTC) for eradication of thyroid remnant after total thyroidectomy or, in patients with metastatic disease, for curative or palliative treatment. In past years, thyroid remnant ablation was indicated in almost every patient with a diagnosis of DTC. Nowadays, careful revision of patients' outcome has introduced the concept of risk-based selection of patients candidate to thyroid remnant ablation. The present review aims to underline the indications for thyroid remnant ablation and to address methodologies to be employed.

Novel and Practical Scoring Systems for the Diagnosis of Thyroid Nodules

Objective

The clinical management of patients with thyroid nodules that are biopsied by fine-needle aspiration cytology and yield indeterminate results remains unsettled. The BRAF V600E mutation has dubious diagnostic value due to its low sensitivity. Novel strategies are urgently needed to distinguish thyroid malignancies from thyroid nodules.

Design

This prospective study included 504 thyroid nodules diagnosed by ultrasonography from 468 patients, and fine-needle aspiration cytology was performed under ultrasound guidance. Cytology and molecular analysis, including BRAF V600E, RET/PTC1 and RET/PTC3, were conducted simultaneously. The cytology, ultrasonography results, and mutational status were gathered and analyzed together. Predictive scoring systems were designed using a combination of diagnostic parameters for ultrasonography, cytology and genetic analysis. The utility of the scoring systems was analyzed and compared to detection using the individual methods alone or combined.

Result

The sensitivity of scoring system^a (ultrasonography, cytology, BRAF V600E, RET/PTC) was nearly identical to that of scoring system^b (ultrasonography, cytology, BRAF V600E); these were 91.0% and 90.2%, respectively. These sensitivities were significantly higher than those obtained using FNAC, genetic analysis and US alone or combined; their sensitivities were 63.9%, 70.7% and 87.2%, respectively. Scoring system^c (ultrasonography, cytology) was slightly inferior to the former two scoring systems but still had relatively high sensitivity and specificity (80.5% and 95.1%, respectively), which were significantly superior to those of single cytology, ultrasonography or genetic analysis. In nodules with uncertainty cytology, scoring system^a, scoring system^b and scoring system^c could elevate the malignancy detection rates to 69.7%, 69.7% and 63.6%, respectively.

Conclusion

These three scoring systems were quick for clinicians to master and could provide quantified information to predict the probability of malignant nodules. Scoring system^b is recommended for improving the detection rate among nodules of uncertain cytology.

Significance of the BRAF mRNA Expression Level in Papillary Thyroid Carcinoma: An Analysis of The Cancer Genome Atlas Data

Background

BRAF^V600E is the most common mutation in papillary thyroid carcinoma (PTC), and it is associated with high-risk prognostic factors. However, the significance of the BRAF mRNA level in PTC remains unknown. We evaluated the significance of BRAF mRNA expression level by analyzing PTC data from The Cancer Genome Atlas (TCGA) database.

Methods

Data from 499 patients were downloaded from the TCGA database. After excluding other PTC variants, we selected 353 cases of classic PTC, including 193 cases with BRAF^V600E and 160 cases with the wild-type BRAF. mRNA abundances were measured using RNA-Seq with the Expectation Maximization algorithm.

Results

The mean BRAF mRNA level was significantly higher in BRAF^V600E patients than in patients with wild-type BRAF (197.6 vs. 179.3, p = 0.031). In wild-type BRAF patients, the mean BRAF mRNA level was higher in cases with a tumor > 2 cm than those with a tumor ≤ 2.0 cm (189.4 vs. 163.8, p = 0.046), and was also higher in cases with lymph node metastasis than in those without lymph node metastasis (188.5 vs. 157.9, p = 0.040). Within BRAF^V600E patients, higher BRAF mRNA expression was associated with extrathyroidal extension (186.4 vs. 216.4, p = 0.001) and higher T stage (188.1 vs. 210.2, p = 0.016).

Conclusions

A higher BRAF mRNA expression level was associated with tumor aggressiveness in classic PTC regardless of BRAF mutational status. Evaluation of BRAF mRNA level may be helpful in prognostic risk stratification of PTC.

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.

B-Raf mutation and papillary thyroid carcinoma patients

Thyroid carcinoma is the most prevalent endocrine neoplasm globally. In the majority of thyroid carcinoma cases, a positive prognosis is predicted following administration of the appropriate treatment. A wide range of genetic alterations present in thyroid carcinoma exert their oncogenic actions partially through the activation of the mitogen-activated protein kinase pathway, with the B-Raf mutation in particular being focused on by experts for decades. The B-Raf gene has numerous mutations, however, V600E presents with the highest frequency. It is believed that the existence of the V600E mutation may demonstrate an association with the clinicopathological characteristics of patients, however, inconsistencies remain in the literature. A number of explanatory theories have been presented in order to resolve these discrepancies. Recently, it has been suggested that the V600E mutation may function as a target in a novel approach that may aid the diagnosis and prognosis of thyroid carcinoma, with a number of vying methods put forward to that effect. The current review aims to assist researchers in further understanding the possible association between B-Raf mutations and thyroid carcinoma.

Relationship of Focally Amplified Long Noncoding on Chromosome 1 (FAL1) lncRNA with E2F Transcription Factors in Thyroid Cancer

Recent functional genomic studies revealed that the oncogenic activity of focally amplified lncRNA on chromosome 1 (FAL1, ENSG00000228126) contributes to tumor growth by p21 repression in human cancers. However, the expression of FAL1 was not investigated in papillary thyroid cancer (PTC). We aimed to determine if FAL1 was up-regulated in PTC compared to paired contralateral normal thyroid tissues, and to investigate the potential targets of this lncRNA and its clinicopathological significance in PTC. We analyzed FAL1 and p21 expression levels in 100 PTC samples and matched normal thyroid tissue by qRT-PCR. Using lncRNA microarray data from the Gene Expression Omnibus (accession no. GSE61763), we explored potential targets of FAL1 by Gene Set Enrichment Analysis, followed by verification by qRT-PCR in our PTC samples. A cross-sectional observational study was conducted to investigate the relationship between patients' clinicopathological features and FAL1 expression. FAL1 expression was significantly higher in PTC than in paired normal thyroid tissues (paired t test, P < 0.001). p21 mRNA expression was also increased, not decreased, in PTC, and had no correlation with FAL1 expression (r = 0.0897, P = 0.4002). Gene Set Enrichment Analysis, using publicly available microarray data, indicated that a gene set related to the cell cycle, including E2F transcription factors 1 and 2, and cyclin D1, was coordinately enriched among samples with high FAL1 expression. A volcano plot showed that E2F1, E2F2, and VEGFA mRNAs were increased in the high FAL1 samples. In clinicopathological analyses, multifocality was more frequently observed in PTC patients with high FAL1 (P = 0.018). Multivariate analysis showed that high FAL1 expression increased the risk of multifocality (after adjustment for clinical variables, OR = 4.019, CI = 1.041-11.020, P = 0.043). FAL1 may have a role in cell-cycle progression and may be associated with aggressive tumor behavior in PTC.

BRAF V600E and decreased NIS and TPO expression are associated with aggressiveness of a subgroup of papillary thyroid microcarcinoma

BACKGROUND

Thyroid cancer incidence has dramatically increased worldwide over the last two decades. The rise is mostly due to an increased detection of small papillary thyroid carcinomas (PTCs) (≤20  mm), predominantly microPTC (≤10  mm). Although small tumors generally have an excellent outcome, a considerable percentage may have a more aggressive disease and worse prognosis. The clinical challenge is to preoperatively identify those tumors that are more likely to recur.

AIM

To improve risk stratification and patient management, we sought to determine the prognostic value of BRAF V600E, NRAS or RET/PTC mutations in patients with PTC measuring <20  mm, mainly microPTC.

METHODS

The prevalence of RET/PTC fusion genes was examined by quantitative RT-PCR. BRAF V600E and NRAS Q61 mutations were determined by PCR sequencing. To further elucidate why some small PTC are less responsive to radioactive iodine treatment therapy, we explored if these genetic alterations may modulate the expression of iodine metabolism genes (NIS, TPO, TG, TSHR and PDS) and correlated with clinico-pathological findings that are predictors of recurrence.

RESULTS

This study shows that tumors measuring ≤20  mm exhibited higher prevalence of BRAF V600E mutation, which correlated with aggressive histopathological parameters, higher risk of recurrence, and lower expression of NIS and TPO. Although this correlation was not found when microPTC were evaluated, we show that tumors measuring 7-10  mm, which were positive for BRAF mutation, presented more aggressive features and lower expression of NIS and TPO.

CONCLUSION

We believe that our findings will help to decide the realistic usefulness of BRAF V600E mutation as a preoperative marker of poor prognosis in small PTC, primarily in microPTC.

First-Line Use of Vemurafenib to Enable Thyroidectomy and Radioactive Iodine Ablation for BRAF-Positive Metastatic Papillary Thyroid Carcinoma: A Case Report

Background. Patients with metastatic or radioactive iodine refractory papillary thyroid carcinoma (PTC) have poor prognosis due to ineffective therapy for this condition beyond surgery and radioactive iodine (RAI or ¹³¹I). BRAF mutation occurs in more than 44% of PCT. Tyrosine kinase inhibitors, the most commonly used agents for these patients, have weak BRAF inhibition activity. BRAF inhibitors have demonstrated promising efficacy in relapsed metastatic PCT after standard treatment, though they are not currently approved for this indication. Case Presentation. We present the case of a 48-year-old Hispanic male who initially presented with columnar-cell variant subtype of PTC and positive BRAFV600E mutation. The patient had widespread bulky metastases to lungs, chest wall, brain, and bone. Discussion. Initial use of vemurafenib demonstrated a 42% cytoreduction of targeted pulmonary metastases and facilitated thyroidectomy and RAI treatment. The patient achieved a durable response over 21 months in the setting of widely metastatic disease. Conclusion. Vemurafenib may be effectively used for cytoreduction in patients with bulky metastatic PTC to bridge them to thyroidectomy and RAI treatment.

TERT Promoter Mutations in Papillary Thyroid Microcarcinomas

BACKGROUND

Small papillary thyroid carcinomas have contributed to the worldwide increased incidence of differentiated thyroid cancer observed over the past decades. However, the mortality rate has not changed over the same period of time, raising questions about the possibility that thyroid cancer patients, especially those with small tumors, are overdiagnosed and overtreated. Molecular prognostic marker able to discriminate aggressive thyroid cancers from those with an indolent course would be of great relevance to tailor the therapeutic approach and reduce overtreatment. Mutations in the TERT promoter were recently reported to correlate strongly with aggressiveness in advanced forms of thyroid cancer, holding promise for a possible clinical application. The occurrence and potential clinical relevance of TERT mutations in papillary thyroid microcarcinomas (mPTCs) is currently unknown. This study aimed to analyze the occurrence of two TERT promoter mutations (-124C>T and -146C>T) and their potential association with unfavorable clinical features in a large cohort of mPTCs.

METHODS

A total of 431 mPTCs cases were collected from six Italian institutions, and TERT promoter mutational status was assessed by a next-generation sequencing approach.

RESULTS

TERT promoter mutations were found in 4.7% of the analyzed mPTCs, showing that even microcarcinomas carry mutations in this gene. Correlation analysis showed that TERT promoter mutations are not associated with aggressive features or clinical outcome in the cohort analyzed.

CONCLUSIONS

TERT mutations are present but uncommon in mPTCs. Apparently, in mPTCs, the occurrence of TERT mutations is not correlated with unfavorable clinical features.

BRAF Immunohistochemistry Using Clone VE1 is Strongly Concordant with BRAF(V600E) Mutation Test in Papillary Thyroid Carcinoma

The aim of this study was to investigate the concordance between BRAF(V600E) mutation test and immunohistochemistry (IHC) and determine the diagnostic accuracy of IHC for papillary thyroid carcinoma (PTC) through a systematic review, meta-analysis, and diagnostic test accuracy review. The current systematic review and meta-analysis included 1141 PTCs in 11 eligible studies. We investigated the concordance rate and performed subgroup analysis using tissue and cytologic samples. Diagnostic test accuracy review was conducted and calculated using the value of area under curve (AUC) on the summary receiver operating characteristic (SROC) curve. The positive rate of BRAF IHC was 79.1% (903 of 1141 cases), and the BRAF(V600E) mutation was found in 76.6% (874 of 1141 cases). The concordance rates were 0.921 (95% confidence interval (CI) 0.877-0.950) and 0.894 (95% CI 0.801-0.946) in IHC positive and negative subgroups, respectively. In the diagnostic test accuracy review, the pooled sensitivity and specificity were 0.97 (95% CI 0.95-0.98) and 0.78 (95% CI 0.72-0.83). The value of AUC on SROC curve was 0.983, and diagnostic odds ratio was 164.28 (95% CI 57.69-467.80). Our results showed that BRAF IHC was strongly concordant with BRAF mutation test and had high diagnostic accuracy in BRAF mutation analysis of PTC.