Induction of BRAF^V600E Mutation in Thyroid Cells Leads to Frequent Hypermethylation

Anaplastic thyroid cancer: Genetic roles, targeted therapy, and immunotherapy

Anaplastic thyroid cancer (ATC) stands as the most formidable form of thyroid malignancy, presenting a persistent challenge in clinical management. Recent years have witnessed a gradual unveiling of the intricate genetic underpinnings governing ATC through next-generation sequencing. The emergence of this genetic landscape has paved the way for the exploration of targeted therapies and immunotherapies in clinical trials. Despite these strides, the precise mechanisms governing ATC pathogenesis and the identification of efficacious treatments demand further investigation. Our comprehensive review stems from an extensive literature search focusing on the genetic implications, notably the pivotal MAPK and PI3K-AKT-mTOR signaling pathways, along with targeted therapies and immunotherapies in ATC. Moreover, we screen and summarize the advances and challenges in the current diagnostic approaches for ATC, including the invasive tissue sampling represented by fine needle aspiration and core needle biopsy, immunohistochemistry, and 18F-fluorodeoxyglucose positron emission tomography/computed tomography. We also investigate enormous studies on the prognosis of ATC and outline independent prognostic factors for future clinical assessment and therapy for ATC. By synthesizing this literature, we aim to encapsulate the evolving landscape of ATC oncology, potentially shedding light on novel pathogenic mechanisms and avenues for therapeutic exploration.

Effect of long-stranded non-coding RNA-BANCR on the progression of thyroid papillary carcinoma and its mechanism

OBJECTIVE

This study aims to investigate the role of BRAF-activated long non-coding RNA (BANCR) in papillary thyroid carcinoma (PTC) progression and its association with clinical and molecular characteristics.

METHODS

Sixteen PTC patients were stratified into four groups (PTC, HT, HT-LNM, and PTC-LNM) based on cervical lymph node metastasis and concurrent Hashimoto's thyroiditis (HT) to explore BANCR expression and its relationship with immune-related factors and tumor microenvironment (TME). Functional assays, including Transwell invasion, colony formation, and CCK8 were performed to evaluate the biological effects of BANCR in PTC cell lines. Bioinformatics analysis further identified BANCR-related pathways and clinical relevance.

RESULTS

BANCR expression was significantly reduced in PTC tissues compared to normal thyroid tissues and was inversely correlated with tumor grade, lymph node metastasis, and T stage. Overexpression of BANCR in PTC cell lines inhibited proliferation, invasion and migration. Bioinformatics analysis demonstrated significant associations between BANCR and immune cell infiltration, immune-related genes, and stromal scores.

CONCLUSIONS

BANCR acts as a tumor suppressor in PTC, suppressing tumor growth and metastasis. These findings provide insights into BANCR's potential as a prognostic marker and therapeutic target in PTC.

High aggressiveness of papillary thyroid cancer: from clinical evidence to regulatory cellular networks

The global incidence of thyroid cancer has increased over recent decades. Papillary thyroid cancer (PTC) is the most common type of thyroid cancer and accounts for nearly 90% of all cases. Typically, PTC has a good prognosis. However, some PTC variants exhibit more aggressive behaviour, which significantly increases the risk of postoperative recurrence. Over the past decade, the high metastatic potential of PTC has drawn the attention of many researchers and these studies have provided useful molecular markers for improved diagnosis, risk stratification and clinical approaches. The aim of this review is to discuss the progress in epidemiology, metastatic features, risk factors and molecular mechanisms associated with PTC aggressiveness. We present a detailed picture showing that epithelial-to-mesenchymal transition, cancer metabolic reprogramming, alterations in important signalling pathways, epigenetic aberrations and the tumour microenvironment are crucial drivers of PTC metastasis. Further research is needed to more fully elucidate the pathogenesis and biological behaviour underlying the aggressiveness of PTC.

BRAFV600E Mutation Analysis in Fine-Needle Aspiration Cytology of Fixed Slide Specimens in Patients with Papillary Thyroid Carcinoma

Background

Papillary thyroid carcinoma is the most frequent type of thyroid cancer. The BRAFV600E mutation is associated with tumor progression. We explored the utility of the BRAF molecular testing on fine needle aspiration fixed specimens of patients with confirmed diagnoses of papillary thyroid carcinoma.

Methods

Fixed thyroid cytology slide specimens of 19 patients with Bethesda II to VI reports were used to detect BRAFV600E mutation by pyrosequencing of extracted DNA.

Results

BRAFV600E mutation was detected in 25% of the specimens with Bethesda category III and IV nodules and in 73% of the nodules with Bethesda category V and VI.

Conclusion

BRAF mutation analysis can be performed on fixed fine needle aspiration cytology specimens. Although the frequency of the mutation is higher in specimens with higher Bethesda category scores, it could support clinical decision-making in thyroid nodules with intermediate Bethesda category scores.

Clinical impact of coexistent chronic lymphocytic thyroiditis on central lymph node metastasis in low- to intermediate-risk papillary thyroid carcinoma: The MASTER study

BACKGROUND

The clinicopathological impact of chronic lymphocytic thyroiditis on patients with papillary thyroid carcinoma patients is still controversial. This study aimed to evaluate the clinicopathologic differences and risk factors for central lymph node metastasis based on the presence of coexistent chronic lymphocytic thyroiditis in patients with low- to intermediate-risk papillary thyroid carcinoma.

METHODS

The medical records of 1,022 patients with low- to intermediate-risk papillary thyroid carcinoma who underwent lobectomy and central neck dissection between June 2020 and March 2022 were reviewed. Differences in clinicopathological factors were analyzed in patients with papillary thyroid carcinoma with or without chronic lymphocytic thyroiditis. Furthermore, risk factors for central lymph node metastasis in patients with low- to intermediate-risk papillary thyroid carcinoma with or without chronic lymphocytic thyroiditis were evaluated.

RESULTS

Among the 1,022 patients with low to intermediate-risk papillary thyroid carcinoma, 102 (10.0%) had coexisting chronic lymphocytic thyroiditis. Female sex (odds ratio = 3.536, P = .001, 95% confidence interval 1.781-8.069), a multifocal tumor (odds ratio = 2.162, P = .001, 95% confidence interval 1.358-3.395), and angiolymphatic invasion (odds ratio = 0.365, P < .001, 95% confidence interval 0.203-0.625) were independent factors associated with patients who had coexisting chronic lymphocytic thyroiditis compared to those without chronic lymphocytic thyroiditis. There were 358 (35%) patients who had central lymph node metastasis. Multivariate analysis showed that younger age (odds ratio = 0.667, P = .013, 95% confidence interval 0.482-0.555), male sex (odds ratio = 0.549, P < .001, 95% confidence interval 0.402-0.751), tumor size >1 cm (odds ratio = 1.454, P = .022, 95% confidence interval 1.053-2.003), extrathyroidal extension (odds ratio = 1.874, P < .001, 95% confidence interval 1.414-2.486), and angiolymphatic invasion (odds ratio = 3.094, P < .001, 95% confidence interval 2.339-4.101) were risk factors for central lymph node metastasis. Angiolymphatic invasion (odds ratio = 11.184, P < .001, 95% confidence interval 3.277-46.199) was identified as the sole independent risk factor for central lymph node metastasis in patients with papillary thyroid carcinoma with coexisting chronic lymphocytic thyroiditis.

CONCLUSION

Our data suggest that patients with low to intermediate-risk papillary thyroid carcinoma with coexistent chronic lymphocytic thyroiditis exhibit different clinical features than patients with papillary thyroid carcinoma without chronic lymphocytic thyroiditis. Additionally, the presence of chronic lymphocytic thyroiditis may be considered a potential factor against central lymph node metastasis.

Association of DNA Promoter Methylation and BRAF Mutation in Thyroid Cancer

The BRAF V600E mutation and DNA promoter methylation play important roles in the pathogenesis of thyroid cancer (TC). However, the association of these genetic and epigenetic alterations is not clear. In this study, using paired tumor and surrounding normal tissue from the same patients, on a genome-wide scale we tried to identify (a) any association between BRAF mutation and DNA promoter methylation, and (b) if the molecular findings may provide a basis for therapeutic intervention. We included 40 patients with TC (female = 28, male = 12) without distant metastasis. BRAF mutation was present in 18 cases. We identified groups of differentially methylated loci (DML) that are found in (a) both BRAF mutant and wild type, (b) only in BRAF mutant tumors, and (c) only in BRAF wild type. BRAF mutation-specific promoter loci were more frequently hypomethylated, whereas BRAF wild-type-specific loci were more frequently hypermethylated. Common DML were enriched in cancer-related pathways, including the mismatch repair pathway and Wnt-signaling pathway. Wild-type-specific DML were enriched in RAS signaling. Methylation status of checkpoint signaling genes, as well as the T-cell inflamed genes, indicated an opportunity for the potential use of PDL1 inhibitors in BRAF mutant TC. Our study shows an association between BRAF mutation and methylation in TC that may have biological significance.