Mutation profile of differentiated thyroid tumours in an Australian urban population

A diagnostic and predictive lncRNA lnc-MPEG1-1 promotes the proliferation and metastasis of papillary thyroid cancer cells by occupying miR-766-5p

Long non-coding RNAs (lncRNAs) act as important biological regulators in human cancers. The purpose of this study was to identify promising biomarkers for improved diagnosis and prognosis of papillary thyroid cancer (PTC). We analyzed the lncRNA expression profile of PTC patients and identified five upregulated and three downregulated lncRNAs as diagnostic biomarkers for PTC in our cohorts, which were confirmed using The Cancer Genome Atlas (TCGA) data. Several lncRNAs have been linked with lymph node (LN) metastasis in patients with PTC. A nomogram combining two lncRNAs, lnc-MPEG1-1:1 and lnc-ABCA12-5:2, with age, T stage, histological type, and predicted LN metastasis was developed. The area under the curve of the developed nomogram was 0.77 (0.73–0.81) in the TCGA training cohort and 0.88 (0.79–0.96) in our validation cohort. In particular, in vivo and in vitro experiments showed that overexpression of lnc-MPEG1-1:1 in PTC cell lines promoted the proliferation and migration of PTC. lnc-MPEG1-1:1 is overexpressed in the cytoplasm of PTC cells and functionally promotes cellular proliferation and migration and functions as a competitive endogenous RNA (ceRNA) by competitively occupying the shared binding sequences of miR-766-5p. lnc-MPEG1-1:1 knockdown suppressed epithelial-mesenchymal transition by miR-766-5p in PTC cells. Collectively, these results revealed a lnc-MPEG1-1:1/miR-766-5p pathway for thyroid cancer progression and suggest that a nomogram effectively predicted the LN metastasis in PTC.

Genetic differences in follicular thyroid carcinoma between Asian and Western countries: a systematic review

Thyroid cancer is the most common endocrine malignancy, and follicular thyroid carcinoma (FTC) is the second most common thyroid cancer following papillary thyroid carcinoma (PTC). RAS mutation and PAX8/PPARγ rearrangement are the two representative genetic alterations in FTC, and there are studies from various countries on their regional frequencies. In this study, we systematically reviewed all available literature aiming to create a complete global map showing the frequencies of these common oncogenic drivers in FTC and to highlight the trends in Asian and Western countries. We performed a search in two electronic databases and identified 71 studies that fit our criteria from 1,329 studies found with our database search terms. There were 54 articles with 1,143 FTC patients and 39 articles with 764 FTC patients available for calculating the frequency of RAS mutation and PAX8/PPARγ rearrangement, respectively. NRAS mutation was the most frequent RAS mutation in all regions, followed by HRAS and KRAS mutation. The frequency of RAS mutation in Asian countries was higher than Western countries (34% vs. 27%, P=0.006) when the mutation detection method was not taken into account. In contrast, this difference in RAS mutation incidence between Asian and Western countries (28% vs. 25%, P=0.47) did not show up in our subgroup analysis incorporating only studies using direct sequencing method. The reported difference of RAS mutation frequency in the previous literature might not be due to the true prevalence of RAS mutation. They could be attributed to the difference in the detection method. As to PAX8/PPARγ rearrangement, Western countries overall had a much higher prevalence than Asian countries (23% vs. 4%, P<0.001), but some European countries had a low incidence, implying regional heterogeneity of PAX8/PPARγ rearrangement. A substantial lack of mutation data in FTC was found in several regions of the world such as Central Asia, Middle East, Africa, and Central and South America. Our results provide the most comprehensive global status of representative genetic alterations in FTC and highlight the similarities and differences between Asian and Western countries.

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

Background

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

Methods

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

Results

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

Conclusions

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

BRAF V600E Gene Mutation Is Associated With Bilateral Malignancy of Papillary Thyroid Cancer

BACKGROUND

Papillary thyroid cancer (PTC) is the most prevalent type of thyroid cancer, which is the most common type of endocrine malignancy. Stratification and personalized surgical management of PTC patients are the major challenges for thyroid surgeons. Though BRAF V600E gene mutation presents in 50-70% of PTCs, it is unclear whether BRAF V600E testing could contribute to clinical practice. Therefore, this study investigated the association between BRAF V600E mutation and clinicopathologic features of PTC to evaluate the benefit of BRAF V600E testing to clinical management of PTC.

METHODS

In total, 145 patients with PTC who underwent bilateral thyroid surgery between July 2016 and December 2016 were included in this study. BRAF V600E mutation status and other clinicopathologic features were evaluated using the resected samples obtained during the surgery.

RESULTS

Bilateral PTC was found in 72.8% of the patients with BRAF V600E mutation, and in 42.0% of the patients without the mutation. In addition, the occurrence of BRAF V600E mutation was higher in cases with bilateral PTC (63.4%) than that in cases with unilateral PTC (42.3%). The difference observed above was statistically significant (P = 0.014 by chi-square test) and BRAF V600E mutation was significantly associated with the bilaterality of PTC (P = 0.0080 by logistic regression).

CONCLUSIONS

Presence of BRAF V600E mutation has been found to be associated with bilaterality of PTC, suggesting that total or near total thyroidectomy should be considered for patients with the mutation.

ROS-induced near-homozygous genomes in thyroid cancer

A near-homozygous genome (NHG) is especially seen in a subset of follicular thyroid cancer of the oncocytic type (FTC-OV). An NHG was also observed in the metabolically relatively quiescent cell lines XTC.UC1, a model for FTC-OV, and in FTC-133, -236 and -238, the latter three derived from one single patient with follicular thyroid cancer. FTC-236 subclones showed subtle whole-chromosome differences indicative of sustained reciprocal mitotic missegregations. Reactive oxygen species (ROS) scavenger experiments reduced the number of chromosomal missegregations in XTC.UC1 and FTC-236, while pCHK2 was downregulated in these cells. Treatment with antimycin A increased ROS indicated by enhanced MitoSOX Red and pCHK2 fluorescence in metaphase cells. In a selected set of oncocytic follicular thyroid tumors, increasing numbers of whole-chromosome losses were observed toward an aggressive phenotype, but with retention of chromosome 7. Together, ROS activates CHK2 and links to the stepwise loss of whole chromosomes during tumor progression in these lesions. We postulate that sequential loss of whole chromosomes is a dominant driver of the oncogenesis of a subset of follicular thyroid tumors.

Role of molecular markers to predict distant metastasis in papillary thyroid carcinoma: Promising value of TERT promoter mutations and insignificant role of BRAF mutations—a meta-analysis

The presence of distant metastasis is associated with an adverse outcome in papillary thyroid cancer. We performed a meta-analysis to investigate the role of molecular markers as predictors for distant metastasis in papillary thyroid cancer. Four electronic databases including PubMed, Web of Science, Scopus, and Virtual Health Library were searched, and odds ratio and its 95% confidence interval concerning the association of BRAF, RAS, and TERT promoter mutations and RET/PTC rearrangements with distant metastasis were calculated using random-effects model. In total, 42 studies with 11,109 papillary thyroid cancers were included for meta-analyses. Overall, the presence of TERT promoter (odds ratio = 5.95; 95% confidence interval = 2.95–11.99), RAS mutations (odds ratio = 2.5; 95% confidence interval = 1.00–6.22), and RET/PTC rearrangements (odds ratio = 1.92; 95% confidence interval = 1.03–3.56) were found to be associated with a significantly increased risk for distant metastasis. BRAF mutations were not associated with an elevated risk for distant metastasis (odds ratio = 0.79; 95% confidence interval = 0.54–1.16). In conclusion, our study demonstrated the promising value of few molecular biomarkers, especially TERT promoter mutations in predicting distant metastasis in papillary thyroid cancers, while BRAF mutations showed no association with distant metastasis. Our study affirms the value of selected mutations for tumor risk stratification and assessment of patients’ prognosis.

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.

Activating BRAF Mutations Detected in Mixed Hürthle Cell Carcinoma and Multifocal Papillary Carcinoma of the Thyroid Gland

Despite the increase in the incidence of thyroid carcinomas, the occurrence of collision tumors in the thyroid remains a rare event. We present the case of a 69-year-old female who presented to the emergency department with a chief complaint of painful neck swelling. Imaging revealed a large right hemithyroid mass and a left hemithyroid nodule. Fine needle aspiration of the lesions and subsequent total thyroidectomy revealed a Hürthle cell carcinoma in the right lobe and bilateral multicentric papillary carcinoma foci, including 2 foci with a classical pattern and 1 encapsulated follicular variant in the isthmus. BRAF gene mutation analysis revealed V600E gene mutation in the classical variants of papillary carcinoma and in the Hürthle cell carcinoma. The focus of follicular variant of papillary carcinoma in the isthmus and a sample from normal thyroid tissue did not harbor BRAF mutations. This case is remarkable in being an unusual report of a follicular Hürthle cell carcinoma harboring the BRAF V600E mutation and occurring in collision with multifocal papillary carcinoma. Documentation of such cases is important as it helps better understand the pathogenesis, clinical behavior, and radiologic findings of such rare lesions and to determine the optimal treatment modalities.

The Risk of Relapse in Papillary Thyroid Cancer (PTC) in the Context of BRAFV600E Mutation Status and Other Prognostic Factors

INTRODUCTION

The risk of over-treatment in low-advanced PTC stages has prompted clinicians to search for new reliable prognostic factors. The presence of BRAF mutation, the most frequent molecular event in PTC, seems to be a good candidate. However, there is still lack of randomised trials and its significance has been proved by retrospective analyses, involving a large group of patients. The question arises whether this factor is useful in smaller populations, characterised for specialised centres. Thus, the aim of the study was to evaluate the use of BRAF mutation as a potential predictive marker in PTC patients.

MATERIAL

233 PTC subjects treated between 2004-2006, were retrospectively analysed. Stage pT1 was diagnosed in 64.8% patients and lymph node metastases in 30.9%. Median follow-up was 7.5 years. BRAFV600E mutation was assessed postoperatively in all cases.

RESULTS

BRAF V600E mutation was found in 54.5%. It was more frequent in patients > 45 years (p=0.0001), and associated with larger tumour size (p=0.004). Patients with tumours <= 10 mm were over-represented among BRAF negative population (p=0.03). No association between BRAF mutation and other clinicopathological factors was observed. BRAF status was associated neither with relapse nor with disease-free survival (DFS) (p=0.76). Nodal status, extrathyroidal invasion and tumour size significantly influenced DFS.

CONCLUSION

The risk of PTC recurrence is mainly related to the presence of lymph node metastases and extrathyroidal invasion, whereas no impact of BRAF V600E mutation has been demonstrated.