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

EphB3 protein is a potential ancillary diagnostic biomarker for thyroid cancers

OBJECTIVE

To investigate the expression of ephrin type B receptor 3 (EphB3) in thyroid tumors and its usage as an ancillary diagnostic biomarker for thyroid tumors.

METHODS

Formalin-fixed and paraffin-embedded (FFPE) tissue samples (78 cases) and FNAC samples (57 cases) were assessed with the EphB3 antibody using immunohistochemistry. PTC and other thyroid follicular tumors were compared regarding their EphB3 expression. Sanger sequencing was used to assess for the presence of a BRAF V600E mutation.

RESULTS

EphB3 was positive in 81.8 % (27/33) of papillary thyroid carcinoma (PTC), 83.3 % (5/6) of medullary thyroid carcinoma (MTC), 25 % (1/4) of hyperplastic/adenomatoid nodule (HN), 14.3 % (1/7) of follicular adenoma (FA), and negative in follicular tumors of uncertain malignant potential (FT-UMP) (0/13), noninvasive follicular neoplasm with papillary-like nuclear features (NIFTP) (0/7), thyroid follicular carcinoma (TFC) (0/4), Hashimoto's thyroiditis (0/4), and normal thyroid follicular tissues (0/33). In cellular blocks, EphB3 was positive in 87.1 % (20/23) of PTC, 75 % (3/4) of MTC, 20 % (2/10) of HN, and negative in atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) (0/20) and normal thyroid follicular cells (0/10).

CONCLUSION

EphB3 is expressed in the majority of PTC, but less so in benign follicular nodules. EphB3 expression in fine needle aspiration cytology (FNAC) specimens can be used as a diagnostic tool to differentiate thyroid cancer from other follicular lesions in its differential diagnosis, especially AUS/FLUS and PTC.

Clinicopathologic Characteristics of Pediatric Follicular Variant of Papillary Thyroid Carcinoma Subtypes: A Retrospective Cohort Study

Introduction: Follicular patterned thyroid nodules with nuclear features of papillary thyroid carcinoma (PTC) encompass a range of diagnostic categories with varying risks of metastatic behavior. Subtypes include the invasive encapsulated follicular variant of PTC (Ienc-fvPTC) and infiltrative fvPTC (inf-fvPTC), with tumors lacking invasive features classified as noninvasive follicular thyroid neoplasms with papillary-like features (NIFTPs). This study aimed to report the clinical and histological features of pediatric cases meeting criteria for these histological subtypes, with specific focus on Ienc-fvPTC and inf-fvPTC. Methods: In this retrospective cohort study, pediatric patients with thyroid neoplasms showing follicular patterned growth and nuclear features of PTC noted on surgical pathology between January 2010 and January 2021 were retrospectively reviewed and classified according to the recent 2022 World Health Organization (WHO) criteria. Clinical and histopathologic parameters were described for NIFTP, Ienc-fvPTC, and inf-fvPTC subtypes, with specific comparison of Ienc-fvPTC and inf-fvPTC cases. Results: The case cohort included 42 pediatric patients, with 6 (14%), 25 (60%), and 11 (26%) patients meeting criteria for NIFTP, Ienc-fvPTC, and inf-fvPTC, respectively. All cases were rereviewed, and 5 patients originally diagnosed with Ienc-fvPTC before 2017 were reappraised as having NIFTPs. The NIFTP cases were encapsulated tumors without invasive features, lymph node or distant metastasis, or disease recurrence. Ienc-fvPTC tumors demonstrated clearly demarcated tumor capsules and capsular/vascular invasion, while inf-fvPTC tumors displayed infiltrative growth lacking a capsule. inf-fvPTC cases had increased prevalence of malignant preoperative cytology, lymph node metastasis, and distant metastasis (p < 0.01). These cases were treated with total thyroidectomy, lymph node dissection, and subsequent radioactive iodine therapy. Preliminary genetic findings suggest a predominance of fusions in inf-fvPTC cases versus point mutations in Ienc-fvPTC (p = 0.02). Conclusions: Pediatric NIFTP and fvPTC subtypes appear to demonstrate alignment between clinical and histological risk stratification, with indolent behavior in Ienc-fvPTC and invasive features in inf-fvPTC tumors.

Prevalence of Postoperatively Detected High-risk Features in 2- to 4-cm Papillary Thyroid Cancers

CONTEXT

The 2015 American Thyroid Association guidelines proposed thyroid lobectomy as an acceptable option for 1- to 4-cm papillary thyroid cancers (PTC) without extrathyroidal extension (ETE) or lymph node (LN) metastasis. However, high-risk features are often detected postoperatively, even in tumors that are considered low risk on preoperative workup. A continued evaluation is necessary to determine the optimal treatment strategies.

OBJECTIVE

We examined the frequency of preoperatively and postoperatively detected high-risk features in 2- to 4-cm PTCs to assess the appropriate surgical extent.

METHODS

All patients who underwent a thyroid surgery between 2015 and 2020 with a final diagnosis of 2- to 4-cm PTC were selected. Demographics, preoperative findings, perioperative course, and surgical pathology were retrospectively analyzed.

RESULTS

Of the entire study cohort (N = 424), 244 (57.5%) patients had at least 1 of the following high-risk features: gross ETE (18.6%), distant metastasis (1.2%), >3 LN involvement with extranodal extension (24.8%), any LN > 3 cm (0.5%), positive margin (13.2%), TERT mutation (2.6%), vascular invasion (10.8%), cN1 disease (28.5%), and > 5 LN involvement (30.4%). Two hundred patients had neither ETE nor LN metastasis on preoperative imaging, but 62/200 (31.0%) were found to have at least 1 of the aforementioned high-risk features on final pathology. Preoperative imaging had sensitivities of 75.9% and 44.4% for detecting gross ETE and LN metastasis, respectively.

CONCLUSION

A significant portion of patients with 2- to 4-cm PTCs, including those who preoperatively met the criteria for lobectomy, were found to have high-risk features on final pathology. Careful patient selection and appropriate counseling are necessary when considering lobectomy for tumors greater than 2 cm.

Non-invasive follicular neoplasm with papillary-like nuclear features: a challenging and infrequent entity in Argentina

PURPOSE

Non-invasive encapsulated follicular variant of papillary thyroid cancer was reclassified as non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). These neoplasms have an extremely low malignant potential. The aim of this study was (1) to assess the prevalence of NIFTP in patients with papillary thyroid carcinoma, (2) to evaluate their outcomes, and (3) to determine their molecular profile.

METHODS

Multicenter, descriptive, retrospective study. Patients with papillary thyroid cancer diagnosed from January 2006 to December 2016 from 11 referral centers were included. Diagnosis of NIFTP was based on criteria described by Nikiforov et al. in 2018. At least two pathologists agreed on the diagnosis. Two thousand six hundred and seventy-seven papillary thyroid cancer patients were included; 456 (17%) of them were follicular variant papillary thyroid cancer, and 30 (1.12%) fulfilled diagnostic criteria for NIFTP.

RESULTS

Each of the 30 included patients underwent a total thyroidectomy, and 50% were treated with radioiodine (median dose 100 mCi). After a median follow-up of 37 months, 84% of patients had an excellent response, 3% had an indeterminate response and data was missing in the remaining 13%. No metastatic lymph nodes, distant metastases or recurrences were found. RAS mutations were detected in 4 patients (13%).

CONCLUSION

The prevalence of NIFTP in our series is amongst the lowest reported. Excellent outcomes of patients underscore their low malignant potential. Molecular findings differ from other series, probably related to environmental or ethnic features of our population and the meticulous criteria for diagnosing NIFTP.

PEAC: An Ultrasensitive and Cost-Effective MRD Detection System in Non-small Cell Lung Cancer Using Plasma Specimen

Circulating tumor DNA (ctDNA), a tumor-derived fraction of cell-free DNA (cfDNA), has emerged as a promising marker in targeted therapy, immunotherapy, and minimal residual disease (MRD) monitoring in postsurgical patients. However, ctDNA level in early-stage cancers and postsurgical patients is very low, which posed many technical challenges to improve the detection rate and sensitivity, especially in the clinical practice of MRD detection. These challenges usually include insufficient DNA input amount, limit of detection (LOD), and high experimental costs. To resolve these challenges, we developed an ultrasensitive ctDNA MRD detection system in this study, namely PErsonalized Analysis of Cancer (PEAC), to simultaneously detect up to 37 mutations, which account for 70–80% non-small cell lung cancer (NSCLC) driver mutations from low plasma sample volume and enables LOD of 0.01% at a single-site level. We demonstrated the high performance achieved by PEAC on both cfDNA reference standards and clinical plasma samples from three NSCLC patient cohorts. For cfDNA reference standards, PEAC achieved a specificity of 99% and a sensitivity of 87% for the mutations at 0.01% allele fraction. In the second cohort, PEAC showed 100% concordance rate between ddPCR and Next-generation sequencing (NGS) among 29 samples. In the third cohort, 22 of 59 patients received EGFR TKI treatment. Among them, three in four patients identified low level actionable gene mutations only by PEAC had partial responses after targeted therapy, demonstrating high ctDNA detection ability of PEAC. Overall, the developed PEAC system can detect the majority of NSCLC driver mutations using 8–10 ml plasma samples, and has the advantages of high detection sensitivity and lower costs compared with the existing technologies such as ddPCR and NGS. These advantages make the PEAC system quite appropriate for ctDNA and MRD detection in early-stage NSCLC and postsurgical recurrence monitoring.

The Incidence of Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features: A Meta-Analysis Assessing Worldwide Impact of the Reclassification

Background: Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) reclassification has significantly influenced the field of thyroidology. However, the extent of this impact depends upon the incidence of NIFTP in a given population. In this meta-analysis, we aimed to obtain robust information about the actual incidence of NIFTP worldwide by reviewing the published data. Methods: Comprehensive literature search was performed using electronic databases of PubMed and Web of Science over a five-year period (January 1, 2016, to January 30, 2021). The incidence of NIFTP was calculated by dividing the number of NIFTPs by the number of papillary thyroid carcinomas (PTCs). Meta-analysis of proportion and their 95% confidence interval [CI] were pooled using the random-effect model. Heterogeneity across the included studies was assessed using I² statistics. Egger's regression test and funnel plot of estimates were used to evaluate the publication bias. p-Value <0.05 was considered significant. Results: From 505 publications, we included 50 studies, all retrospective, with 100,780 PTCs and 3990 NIFTP from 92 institutions worldwide. The overall incidence of NIFTP was 6.0% [CI 4.4-8.2] among PTCs or thyroid malignancies with a high level of heterogeneity among the included studies (I² = 98.6%). NIFTP incidence was largely similar in North America and Europe (9.3% vs. 9.6%), with a significantly lower overall rate in Asia (2.1%). There was a significant decline in the reported incidence of NIFTP in non-Asian studies published after 2017 (p = 0.002). On applying our data on global thyroid cancer statistics, this reclassification would affect ∼30,881 patients annually, with a lower impact in Asia compared with North America and Europe. Conclusions: This comprehensive meta-analysis confirms that the worldwide NIFTP incidence is much lower than estimated initially. The NIFTP rates are significantly lower in Asian compared with North American and European countries. Apart from geography, NIFTP rates are significantly influenced by the nature of study, type of database used for sample collection, and the diagnostic criteria used. Introduction of NIFTP may potentially spare over 30,000 patients worldwide annually from clinical and psychological consequences of a thyroid cancer diagnosis.

Higher EU-TIRADS-Score Correlated with BRAF V600E Positivity in the Early Stage of Papillary Thyroid Carcinoma

The data demonstrating a correlation between sonographic markers of malignancy of thyroid cancer (TC) and its genetic status are scarce. This study aimed to assess whether the addition of genetic analysis at the preoperative step of TC patients' stratification could aid their clinical management. The material consisted of formalin-fixed paraffin-embedded tumor fragments of 49 patients who underwent thyroidectomy during the early stages of papillary TC (PTC). Tumor DNA and RNA were subjected to next-generation sequencing (NGS) on Ion Proton using the Oncomine™ Comprehensive Assay panel. We observed a significant correlation between BRAF V600E and a higher EU-TIRADS score (p-value = 0.02) with a correlation between hypoechogenicity and taller-than-wide tumor shape in analysed patients. There were no other significant associations between the identified genetic variants and other clinicopathological features. For TC patient's stratification, a strong suspicion of BRAF V600E negativity in preoperative management of TC patients could limit the over-treatment of asymptomatic, very low-risk, indolent disease and leave room for active surveillance.

Novel Therapeutics in Radioactive Iodine-Resistant Thyroid Cancer

Iodine-resistant cancers account for the vast majority of thyroid related mortality and, until recently, there were limited therapeutic options. However, over the last decade our understanding of the molecular foundation of thyroid function and carcinogenesis has driven the development of many novel therapeutics. These include FDA approved tyrosine kinase inhibitors and small molecular inhibitors of VEGFR, BRAF, MEK, NTRK and RET, which collectively have significantly changed the prognostic outlook for this patient population. Some therapeutics can re-sensitize de-differentiated cancers to iodine, allowing for radioactive iodine treatment and improved disease control. Remarkably, there is now an FDA approved treatment for BRAF-mutated patients with anaplastic thyroid cancer, previously considered invariably and rapidly fatal. The treatment landscape for iodine-resistant thyroid cancer is changing rapidly with many new targets, therapeutics, clinical trials, and approved treatments. We provide an up-to-date review of novel therapeutic options in the treatment of iodine-resistant thyroid cancer.

Comparison of Suicide Risk by Mental Illness: a Retrospective Review of 14-Year Electronic Medical Records

BACKGROUND

Korea is one of the countries with the highest rate of suicide, while suicidality is known to be closely related to mental illnesses. The study aimed to evaluate the suicide rates in psychiatric patients, to compare it to that of the general population, and to investigate the differences among psychiatric diagnoses and comorbidities.

METHODS

Medical records and mortality statistics of psychiatric patients at Seoul National University Hospital from 2003 to 2017 were reviewed. The standardized mortality ratio (SMR) for suicide was calculated to compare the psychiatric patients with the general population. The diagnosis-specific standardized mortality rate and hazard ratio (HR) were adjusted by age, sex, and psychiatric comorbidity (i.e., personality disorder and/or pain disorder).

RESULTS

A total of 40,692 survivors or non-suicidal deaths and 597 suicidal death were included. The suicide rate among psychiatric patients was 5.13-fold higher than that of the general population. Psychotic disorder had the highest SMR (13.03; 95% confidence interval [CI], 11.23-15.03), followed by bipolar disorder (10.26; 95% CI, 7.97-13.00) and substance-related disorder (6.78; 95% CI, 4.14-10.47). In survival analysis, psychotic disorder had the highest HR (4.16; 95% CI, 2.86-6.05), which was further increased with younger age, male sex, and comorbidity of personality disorder.

CONCLUSION

All psychiatric patients are at a higher risk of suicide compared to the general population, and the risk is highest for those diagnosed with psychotic disorder.

Molecular testing and thyroid nodule management in North America

The incidence of thyroid cancer is rising for a variety of reasons. At the same time, the nomenclature revision of non-invasive encapsulated follicular-variant PTC to noninvasive follicular neoplasm with papillary-like nuclear features (NIFTP) has modified the incidence of thyroid cancer. Given that thyroid neoplasia is a molecular event, it is important for the thyroid physician to evaluate each patient systematically. Most thyroid cancers are sporadic; however, some are familial and may be associated with syndromes with genetic implications. Advances in radiologic imaging have made ultrasonography a near equivalent of gross examination. The American College of Radiology Thyroid Imaging, Reporting and Data System (ACR TI-RADS) classifies nodules from TR1 to TR5 and is valuable in determining which patients should be guided toward fine-needle aspiration (FNA) sampling. While FNA procedures and processing may be varied, the key elements are cytologic diagnosis and collection of samples for potential molecular testing. The Bethesda System for Reporting Thyroid Cytology (BSRTC) is commonly used and categorizes each FNA specimen into one of six diagnoses. The indeterminate diagnoses with risk of malignancy (ROM) ranging from 10-75% comprise approximately 30% of thyroid FNA cases and for these, molecular testing is beneficial. In North America, the two most common molecular platforms are Veracyte Afirma GSC and ThyroSeq v3. Both panels cover an extensive array of genomic alterations associated with thyroid neoplasia and a negative result from either test effectively refines the ROM of an Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance (AUS/FLUS) or Follicular Neoplasm/Suspicious for a Follicular Neoplasm (FN/SFN) diagnosis to 3-4%. Given that the refined ROMs are comparable to that of a Benign BSRTC diagnosis, these patients are recommended for observation of their nodules. However, differences exist in the implication of Afirma GSC-Suspicious and ThyroSeq v3-Positive molecular results with regard to the probability of cancer. For either test, the molecular test result should be integrated with other clinical parameters to determine if surgery is indicated and, if so, the extent of surgery.

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.

Molecular Profiling of Follicular Variant of Papillary Thyroid Cancer

The molecular features of the follicular variant of papillary thyroid cancer are closely related to the clinical behavior of the tumor and the prognosis of the disease. BRAF-V600E mutations in patients with a follicular variant of papillary thyroid cancer have not been identified; however, the majority of patients had T3-4N0M0 stage of the disease. Changes in the expression of transcription and growth factors and AKT/m-TOR signaling pathway components were detected. In addition, hyperexpression of m-TOR and 4EBP1 kinases and CAIX enzyme was shown compared to the classical variant of papillary thyroid cancer, where an increase in the nuclear factor NF-κB p65 and c-RAF kinase expression was observed.

Circular RNA expression and association with the clinicopathological characteristics in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Circular RNAs (circRNAs) are a novel class of RNAs, with higher stability and tissue specificity, which may be of value as novel clinical markers. High-throughput RNA sequencing was used to profile the expression of circRNAs in 5 pairs of cancer and normal tissues, and reverse transcription-quantitative PCR (RT-qPCR) analysis was employed to verify the results of the RNA sequencing in 45 cases of PTC. The dysregulated circRNA expression and clinicopathological characteristics were assessed and the potential roles of circRNAs in the cellular miRNA and mRNA network were predicted using bioinformatics analysis. The results demonstrated that, compared with normal tissues, a total of 53 circRNAs were dysregulated in tumour tissues, and 8 circRNAs were validated at the mRNA level (P<0.001 and P<0.01). Among those, the expression of chr5:161330882-161336769- (P=0.015), chr9:22046750-22097364+ (P=0.041) and chr8:18765448-18804898- (P=0.036) were obviously associated with the BRAF^V600E mutation, chr12:129699809-129700698- was associated with capsular invasion (P=0.025) and chr5:38523418-38530666- was associated with pT stage (P=0.037) and lymph node metastasis (P=0.002). Therefore, some dysregulated circRNAs were found to be associated with BRAF^V600E mutation, capsular invasion, advanced pT stage and lymph node metastasis of PTC, indicating that circRNAs may be involved in tumourigenesis and cancer progression, and they may be putative biomarkers for the diagnosis and evaluation of progression of PTC.

A Multi-institutional Study of Prevalence and Clinicopathologic Features of Non-invasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features (NIFTP) in Korea

Background

In the present multi-institutional study, the prevalence and clinicopathologic characteristics of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) were evaluated among Korean patients who underwent thyroidectomy for papillary thyroid carcinoma (PTC).

Methods

Data from 18,819 patients with PTC from eight university hospitals between January 2012 and February 2018 were retrospectively evaluated. Pathology reports of all PTCs and slides of potential NIFTP cases were reviewed. The strict criterion of no papillae was applied for the diagnosis of NIFTP. Due to assumptions regarding misclassification of NIFTP as non-PTC tumors, the lower boundary of NIFTP prevalence among PTCs was estimated. Mutational analysis for BRAF and three RAS isoforms was performed in 27 randomly selected NIFTP cases.

Results

The prevalence of NIFTP was 1.3% (238/18,819) of all PTCs when the same histologic criteria were applied for NIFTP regardless of the tumor size but decreased to 0.8% (152/18,819) when tumors ≥1 cm in size were included. The mean follow-up was 37.7 months and no patient with NIFTP had evidence of lymph node metastasis, distant metastasis, or disease recurrence during the follow-up period. A difference in prevalence of NIFTP before and after NIFTP introduction was not observed. BRAF^V600E mutation was not found in NIFTP. The mutation rate for the three RAS genes was 55.6% (15/27).

Conclusions

The low prevalence and indolent clinical outcome of NIFTP in Korea was confirmed using the largest number of cases to date. The introduction of NIFTP may have a small overall impact in Korean practice.