Influence of the BRAF V600E mutation on expression of vascular endothelial growth factor in papillary thyroid cancer

BRAFV600E mutation is associated with better prognoses in radioactive iodine refractory thyroid cancer patients treated with multi-kinase inhibitors: a retrospective analysis of registered clinical trials

BACKGROUND

The antiangiogenic multi-kinase inhibitors (MKIs) apatinib, donafenib, and anlotinib have demonstrated satisfactory efficacy in radioactive iodine refractory differentiated thyroid cancer (RAIR-DTC) in their phase II/III trials. However, the potential impact factors on the efficacy of these MKIs remain unclear.

METHODS

RAIR-DTC patients enrolled in clinical trials of apatinib, donafenib, and anlotinib in our center were retrospectively reviewed. The Kaplan-Meier method was used to examine the relationship between clinicopathological variables and progression-free survival (PFS) and overall survival (OS), followed by a multivariate Cox analysis on PFS.

RESULTS

A total of 71 progressive RAIR-DTC patients were reviewed, of which 26.7% were treated by anlotinib, 45.1% by apatinib, and 28.2% by donafenib. The median follow-up time was 44.1 months, the median PFS was 21.1 months, and the estimated median OS was 47.7 months. PFS and OS showed no significant differences in patients treated with apatinib, donafenib, or anlotinib. In the univariate analyses, patients with BRAFV600E mutation showed longer PFS (HR 0.345, 95% CI 0.187-0.636, p < 0.001) and OS (HR 0.382, 95% CI 0.166-0.878, p = 0.019) compared with patients with wild-type BRAF. Patients with follicular thyroid cancer and bone metastases had shorter PFS, and patients with worse Eastern Cooperative Oncology Group performance status, bone metastases, and a larger tumor burden had shorter OS. In the multivariate Cox analysis, BRAFV600E mutation was the only independent predictor of longer PFS (HR 0.296, 95% CI 0.138-0.638, p = 0.002). The overall response rate and disease control rate didn't differ between BRAFV600E mutation status. Subgroup analysis of PFS in papillary thyroid cancer patients stratified by BRAFV600E mutation status showed that BRAFV600E mutation was associated with longer PFS in all clinicopathological subgroups (hazard ratio < 1).

CONCLUSION

RAIR-DTC patients with BRAFV600E mutation treated with apatinib, donafenib, or anlotinib achieved better prognoses compared with patients with wild-type BRAF, indicating that the genetic background may play a role in predicting the efficacy of MKIs therapies.

TRIAL REGISTRATION

This retrospective cohort included patients in our center from clinical trials of apatinib (NCT02731352, NCT03048877), donafenib (NCT02870569, NCT03602495), and anlotinib (NCT05007093).

Systemic treatments for radioiodine-refractory thyroid cancers

Differentiated thyroid cancers (DTCs) constitute the primary histological subtype within thyroid cancer. Due to DTCs' distinctive radioiodine (RAI) uptake mechanism, standard treatment involving surgery, with or without adjunctive therapy using RAI and levothyroxine inhibition, typically yields favorable prognoses for the majority of patients with DTCs. However, this favorable outcome does not extend to individuals with decreased RAI uptake, termed radioiodine-refractory thyroid cancers (RAI-RTCs). Recent research has revealed that the genetic mutations and gene rearrangements affecting sites such as RTKs, RAS, BRAF and TERTp lead to structural and functional abnormalities in encoded proteins. These abnormalities aberrantly activate signaling pathways like the mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3-hydroxykinase (PI3K) signaling pathways, resulting in thyroid cells dedifferentiation, sodium/iodide symporter (NIS) dysfunction, and consequent the RAI-refractory nature of DTCs. Targeted therapy tailored to mutations presents a promising avenue for the treatment of RAI-RTCs. Lenvatinib and sorafenib, multi-kinase inhibitors, represent the standard first-line systemic treatment options, while cabozantinib is the standard second-line treatment option, for this purpose. Furthermore, ongoing clinical trials are exploring selective kinase inhibitors, immune checkpoint inhibitors, and combination therapies. Notably, numerous clinical trials have demonstrated that selective kinase inhibitors like BRAF, MEK and mTOR inhibitors can restore RAI uptake in tumor cells. However, further validation through multicenter, large-sample, double-blinded randomized controlled trials are essential. Enhanced treatment strategies and innovative therapies are expected to benefit a broader spectrum of patients as these advancements progress.

Immune response and mesenchymal transition of papillary thyroid carcinoma reflected in ultrasonography features assessed by radiologists and deep learning

INTRODUCTION

Ultrasonography (US) features of papillary thyroid cancers (PTCs) are used to select nodules for biopsy due to their association with tumor behavior. However, the molecular biological mechanisms that lead to the characteristic US features of PTCs are largely unknown.

OBJECTIVES

This study aimed to investigate the molecular biological mechanisms behind US features assessed by radiologists and three convolutional neural networks (CNN) through transcriptome analysis.

METHODS

Transcriptome data from 273 PTC tissue samples were generated and differentially expressed genes (DEGs) were identified according to US feature. Pathway enrichment analyses were also conducted by gene set enrichment analysis (GSEA) and ClusterProfiler according to assessments made by radiologists and three CNNs - CNN1 (ResNet50), CNN2 (ResNet101) and CNN3 (VGG16). Signature gene scores for PTCs were calculated by single-sample GSEA (ssGSEA).

RESULTS

Individual suspicious US features consistently suggested an upregulation of genes related to immune response and epithelial-mesenchymal transition (EMT). Likewise, PTCs assessed as positive by radiologists and three CNNs showed the coordinate enrichment of similar gene sets with abundant immune and stromal components. However, PTCs assessed as positive by radiologists had the highest number of DEGs, and those assessed as positive by CNN3 had more diverse DEGs and gene sets compared to CNN1 or CNN2. The percentage of PTCs assessed as positive or negative concordantly by radiologists and three CNNs was 85.6% (231/273) and 7.1% (3/273), respectively.

CONCLUSION

US features assessed by radiologists and CNNs revealed molecular biologic features and tumor microenvironment in PTCs.

Identification of Benzothiazoles Bearing 1,3,4-Thiadiazole as Antiproliferative Hybrids Targeting VEGFR-2 and BRAF Kinase: Design, Synthesis, BIO Evaluation and In Silico Study

Cancer remains a leading cause of death worldwide, often resulting from uncontrolled growth in various organs. Protein kinase inhibitors represent an important class of targeted cancer therapies. Recently, the kinases BRAF and VEGFR-2 have shown synergistic effects on tumor progression. Seeking to develop dual BRAF/VEGFR-2 inhibitors, we synthesized 18 amino-benzothiazole derivatives with structural similarities to reported dual inhibitors. Four compounds-4a, 4f, 4l, and 4r-demonstrated remarkable cytotoxicity, with IC50 values ranging from 3.58 to 15.36 μM, against three cancer cell lines. Furthermore, these compounds showed IC50 values of 38.77-66.22 μM in the case of a normal cell line, which was significantly safer than the reference, sorafenib. Subsequent investigation revealed that compound 4f exhibited the capacity to inhibit the BRAF and VEGFR-2 enzymes, with IC50 values similar to sorafenib (0.071 and 0.194 μM, respectively). Moreover, compound 4f caused G2-M- and S-phase cycle arrest. Molecular modeling demonstrated binding patterns compatible with inhibition for both targets, where 4f exerted the critical interactions in the BRAF site and interacted in the VEGFR-2 site in a manner akin to sorafenib, demonstrating affinity similar to dabrafenib.

CXCL16 promotes tumor metastasis by regulating angiogenesis in the tumor micro-environment of BRAF V600E mutant colorectal cancer

Patients of colorectal cancer (CRC) with BRAF V600E mutation obtain poor prognosis. This study aimed to explore the role and mechanism of BRAF V600E mutation in angiogenesis of tumor micro-environment (TME). It has been reported that CXCL16 expression in TME is closely related to BRAF mutation. Clinicopathological features of CRC with BRAF V600E mutant or wild type were collected in this study. Immunohistochemistry (IHC) assays were conducted to test the expressions of vascular endothelial growth factor (VEGF), CD31 and CXCL16. ROC curve was used to determine the optimal cut off values of CXCL16. A total of 680 patients including 141 BRAF V600E type and 679 wild type were included. BRAF V600E mutant tumors were presented with significant worse clinicopathological features and a shorter overall survival (OS) than wild-type. Besides, chemokines CXCL16 was up-regulated in BRAF V600E mutant tissues and was associated with poorer prognosis. In addition, VEGF levels and vascular endothelial cell density was significantly increased in BRAF mutation. At last, CXCL16 was positively correlated with VEGF expression and vascular endothelial cell density. In conclusion, BRAF V600E mutations may promote metastasis of CRC by regulating CXCL16 expression and promoting angiogenesis in the TME.

New pyrazolylindolin-2-one based coumarin derivatives as anti-melanoma agents: design, synthesis, dual BRAFV600E/VEGFR-2 inhibition, and computational studies

Malignant melanoma is the most invasive skin cancer with the highest risk of death. The inhibition of BRAFV600E appears relevant for overcoming secondary resistance developed during melanoma treatment. BRAFV600E triggers angiogenesis via modification of the expression of angiogenic inducers, which play a crucial role in the metastasis of melanoma. Accordingly, the dual inhibition of the BRAFV600E/VEGFR-2 signaling pathway is considered a rational approach in the design of anti-melanoma candidates. In this study, a new class of pyrazolylindolin-2-one linked coumarin derivatives as dual BRAFV600E/VEGFR-2 inhibitors targeting A375 melanoma cells was designed. Target compounds were tailored to occupy the pockets of BRAFV600E and VEGFR-2. Most of the synthesized compounds demonstrated potent mean growth inhibitory activity against A375 cells. Compound 4j was the most active cytotoxic derivative, displaying an IC50 value at a low micromolar concentration of 0.96 μM with a significant safety profile. Moreover, 4j showed dual potent inhibitory activity against BRAFV600E and VEGFR-2 (IC50 = 1.033 and 0.64 μM, respectively) and was more active than the reference drug sorafenib. Furthermore, derivative 4j caused significant G0/G1 cell cycle arrest, induced apoptosis, and inhibited the migration of melanoma cells. Molecular docking showed that compound 4j achieved the highest ΔG value of -9.5 kcal mol-1 against BRAFV600E and significant ΔG of -8.47 kcal mol-1 against VEGFR-2. Furthermore, the structure-activity relationship study revealed that TPSA directly contributed to the anticancer activity of the tested compounds.

Comparative Analysis of Driver Mutations and Transcriptomes in Papillary Thyroid Cancer by Region of Residence in South Korea

BACKGRUOUND

Radiation exposure is a well-known risk factor for papillary thyroid cancer (PTC). South Korea has 24 nuclear reactors in operation; however, no molecular biological analysis has been performed on patients with PTC living near nuclear power plants.

METHODS

We retrospectively included patients with PTC (n=512) divided into three groups according to their place of residence at the time of operation: inland areas (n=300), coastal areas far from nuclear power plants (n=134), and nuclear power plant areas (n=78). After propensity score matching (1:1:1) by age, sex, and surgical procedure, the frequency of representative driver mutations and gene expression profiles were compared (n=50 per group). Epithelial-mesenchymal transition (EMT), BRAF, thyroid differentiation, and radiation scores were calculated and compared.

RESULTS

No significant difference was observed in clinicopathological characteristics, including radiation exposure history and the frequency of incidentally discovered thyroid cancer, among the three groups. BRAFV600E mutation was most frequently detected in the groups, with no difference among the three groups. Furthermore, gene expression profiles showed no statistically significant difference. EMT and BRAF scores were higher in our cohort than in cohorts from Chernobyl tissue bank and The Cancer Genome Atlas Thyroid Cancer; however, there was no difference according to the place of residence. Radiation scores were highest in the Chernobyl tissue bank but exhibited no difference according to the place of residence.

CONCLUSION

Differences in clinicopathological characteristics, frequency of representative driver mutations, and gene expression profiles were not observed according to patients' region of residence in South Korea.

BRAFV600E Positivity-Dependent Effect of Age on Papillary Thyroid Cancer Recurrence Risk

BRAFV600E positivity is associated with increased aggressiveness of papillary thyroid cancer (PTC), and age is an important prognostic factor. However, the association between age and BRAFV600E positivity and the recurrence risk has not been investigated. This study aimed to investigate the impact of age on recurrence between patients with BRAFV600E-positive and -negative PTC. Patients with PTC who underwent initial thyroid surgery between January 2010 and December 2018 at Seoul St. Mary's Hospital (Seoul, Republic of Korea) were retrospectively reviewed. The BRAFV600E-positive (n = 1768) and BRAFV600E-negative groups (n = 428) were divided into two subgroups: younger (<35 years) and older groups (≥55 years). In the BRAFV600E-positive group, the younger group exhibited higher lymphatic and vascular invasion rates, more positive lymph nodes, higher lymph node ratios, and higher recurrence rates than the older group (5.9% vs. 2.1%). Multivariate analysis revealed that age, lymphatic invasion, and N category were significant risk factors in the BRAFV600E-positive group. In the BRAFV600E-positive group, the younger group had a higher recurrence risk than the older group (OR, 2.528; 95% confidence interval, 1.443-4.430; p = 0.001). In the BRAFV600E-negative group, age had no impact on recurrence risk. These results contribute to tailored treatment strategies and informed patient management.

Hypoxia in Skin Cancer: Molecular Basis and Clinical Implications

Skin cancer is one of the most prevalent cancers in the Caucasian population. In the United States, it is estimated that at least one in five people will develop skin cancer in their lifetime, leading to significant morbidity and a healthcare burden. Skin cancer mainly arises from cells in the epidermal layer of the skin, where oxygen is scarce. There are three main types of skin cancer: malignant melanoma, basal cell carcinoma, and squamous cell carcinoma. Accumulating evidence has revealed a critical role for hypoxia in the development and progression of these dermatologic malignancies. In this review, we discuss the role of hypoxia in treating and reconstructing skin cancers. We will summarize the molecular basis of hypoxia signaling pathways in relation to the major genetic variations of skin cancer.

Role of the Skin Microenvironment in Melanomagenesis: Epidermal Keratinocytes and Dermal Fibroblasts Promote BRAF Oncogene-Induced Senescence Escape in Melanocytes

Simple Summary

Melanoma is a deadly skin cancer caused by the uncontrolled proliferation of melanocytes, a population of specialized cells that produce the skin pigment melanin. An aberrant proliferation of melanocytes is common, manifesting as new moles, and these lesions often remain benign. Only a small fraction of these aberrant melanocytes transition to melanoma (i.e., melanomagenesis). The factors that drive this transition are not fully understood. Recent studies have suggested that other cells—specifically, keratinocytes that make up the upper skin layers and fibroblasts, which are non-specialized cells within the deeper layers of the skin—also contribute to melanomagenesis. Here, employing microscale models that mimicked the skin microenvironment, we investigated the effect of crosstalk between melanocytes as well as keratinocytes and fibroblasts on melanomagenesis. Our findings show that keratinocyte- and fibroblast-derived factors can inhibit the mechanisms that prevent an uncontrolled melanocyte proliferation and contribute to melanomagenesis. Thus, targeting skin microenvironment-derived factors is a potential strategy to prevent melanomagenesis.

Abstract

BRAF^V600E is the most common mutation driver in melanoma. This mutation is known to cause a brief burst of proliferation followed by growth arrest and senescence, which prevent an uncontrolled cell proliferation. This phenomenon is known as oncogene-induced senescence (OIS) and OIS escape is thought to lead to melanomagenesis. Much attention has been focused on the melanocyte-intrinsic mechanisms that contribute to senescence escape. Additional genetic events such as the loss of tumor suppressor PTEN and/or epigenetic changes that contribute to senescence escape have been described. However, the role of the skin microenvironment—specifically, the role of epidermal keratinocytes—on melanomagenesis is not fully understood. In this study, we employ a microfluidic platform to study the interaction between melanocytes expressing the BRAF^V600E mutation as well as keratinocytes and dermal fibroblasts. We demonstrate that keratinocytes suppress senescence-related genes and promote the proliferation of transformed melanocytes. We also show that a keratinocyte-conditioned medium can alter the secretion of both pro- and anti-tumorigenic factors by transformed melanocytes. In addition, we show that melanocytes and keratinocytes from donors of white European and black African ancestry display different crosstalks; i.e., white keratinocytes appear to promote a more pro-tumorigenic phenotype compared with black keratinocytes. These data suggest that keratinocytes exert their influence on melanomagenesis both by suppressing senescence-related genes in melanocytes and by affecting the balance of the melanocyte-secreted factors that favor tumorigenesis.

Kinase-inhibitors for iodine-refractory differentiated thyroid cancer: still far from a structured therapeutic algorithm

The kinase-inhibitors (KIs) sorafenib and lenvatinib demonstrated efficacy in iodine-refractory DTC upon phase III studies. However, evidence allowing a punctual balance of benefits and risks is poor. Furthermore, the lack of a direct comparison hampers to establish the proper sequence of administration. However, some insights may provided: a) indirect comparison between phase III trials showed milder toxicity for sorafenib, which should be preferred in case of cardiovascular comorbidities; b) prospective evidence of efficacy in KIs pre-treated patients is available only for lenvatinib, which should be used as second-line. Promising activity was found for the majority of other tested KIs, but no placebo-controlled trials are available. Emerging, but still early, frontiers include the restoration of iodine-sensitivity and the selective activity on pathogenic mutations. In conclusion, the use of KIs in iodine-refractory DTC is far from a structured therapeutic algorithm.

Tumor Microenvironment-Associated Pericyte Populations May Impact Therapeutic Response in Thyroid Cancer

Thyroid cancer is the most common endocrine malignancy, and aggressive radioactive iodine refractory thyroid carcinomas still lack an effective treatment. A deeper understanding of tumor heterogeneity and microenvironment will be critical to establishing new therapeutic approaches. One of the important influencing factors of tumor heterogeneity is the diversity of cells in the tumor microenvironment. Among these are pericytes, which play an important role in blood vessel stability and angiogenesis, as well as tumor growth and metastasis. Pericytes also have stem cell-like properties and are a heterogeneous cell population, and their lineage, which has been challenging to define, may impact tumor resistance at different tumor stages. Pericytes are also important stroma cell types in the angiogenic microenvironment which express tyrosine-kinase (TK) pathways (e.g., PDGFR-β). Although TK inhibitors (TKI) and BRAF^V600E inhibitors are currently used in the clinic for thyroid cancer, their efficacy is not durable and drug resistance often develops. Characterizing the range of distinct pericyte populations and distinguishing them from other perivascular cell types may enable the identification of their specific functions in the thyroid carcinoma vasculature. This remains an essential step in developing new therapeutic strategies. Also, assessing whether thyroid tumors hold immature and/or mature vasculature with pericyte populations coverage may be key to predicting tumor response to either targeted or anti-angiogenesis therapies. It is also critical to apply different markers in order to identify pericyte populations and characterize their cell lineage. This chapter provides an overview of pericyte ontogenesis and the lineages of diverse cell populations. We also discuss the role(s) and targeting of pericytes in thyroid carcinoma, as well as their potential impact on precision targeted therapies and drug resistance.

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.

Liver X Receptor β Related to Tumor Progression and Ribosome Gene Expression in Papillary Thyroid Cancer

BACKGROUND

Intracellular lipid deposition has been reported in thyroid glands in obese animal and human. To understand the regulatory mechanism of lipid metabolism in thyroid cancer, we investigated the expression status of liver X receptor (LXR) and analyzed its clinicopathological characteristics and molecular biological features.

METHODS

Expression status of LXR and its transcriptional targets in human cancers were analyzed using The Cancer Genome Atlas (TCGA). The gene-sets related to high LXRβ expression was investigated by gene set enrichment analysis (GSEA) using Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways and gene ontology biologic process. Quantitative reverse transcription polymerase chain reaction was performed in thyroid cancer samples using our validation cohort.

RESULTS

In contrast to low expression of LXRα, LXRβ was highly expressed in thyroid cancer compared to the other types of human cancers. High LXRβ expression was correlated with the expression of LXRβ transcriptional targets genes, such as apolipoprotein C1 (APOC1), APOC2, apolipoprotein E (APOE), ATP binding cassette subfamily G member 8 (ABCG8), sterol regulatory elementbinding protein 1c (SREBP1c), and SPOT14. Furthermore, High LXRβ expression group indicated poor clinicopathological characteristics and aggressive molecular biological features independently from the drive mutation status. Mechanistically, high LXRβ expression was coordinately related to ribosome-related gene sets.

CONCLUSION

The mechanistic link between LXRβ and ribosomal activity will be addressed to develop new diagnostic and therapeutic targets in thyroid cancers.

BRAF mutation analysis by ARMS-PCR refines thyroid nodule management

BACKGROUND

Fine-needle aspiration (FNA) of thyroid nodules leads to nearly 25% indeterminate nodules, while BRAF^V600E mutation helps to predicting papillary thyroid carcinoma (PTC). However, the clinical validity and utility of the BRAF^V600E mutation detected using preoperative FNA samples in a large cohort were rarely reported.

AIM

To explore the clinical significance of the BRAF^V600E mutation on preoperative diagnosis and decision-making in a large FNA cohort in China.

DESIGN

This was a prospective study of BRAF^V600E mutation analysis using an amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) in FNA samples.

PATIENTS

The study involved 2640 samples from 2307 patients undergoing FNA procedures in a Chinese medical centre.

RESULTS

A high mutation rate of 86.7% was found in the PTC population. For indeterminate thyroid nodules, the malignant rate of BRAF^V600E+ and BRAF^V600E- was 87.8% and 39.5% in the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) III, and 88.2% and 31.8% in the BSRTC IV, respectively. A cost-effective diagnostic model combining both BSRTC grading and BRAF^V600E mutation status showed the highest sensitivity of 82.9% and specificity of 85.4%. Central lymph node metastasis (CLNM) was independent of the BRAF mutation status and accounted for 34.2% of the patients with PTC. C_T values of BRAF^V600E of patients with PTMC were significantly lower in young patients and patients with CLNM.

CONCLUSIONS

The combined analysis of cytological results and BRAF^V600E mutation is highly recommended in BRAF^V600E high-prevalence regions, including China. Prophylactic central neck dissection should be performed in selected patients without regard to the BRAF mutation status.

Lenvatinib for thyroid cancer treatment: discovery, pre-clinical development and clinical application

Introduction: About one third of patients affected with thyroid cancer present with recurrent disease. Unresectability, advanced disease and radioiodine refractoriness are considered poor prognostic factors. Treatment with small molecules inhibiting molecular signaling can be considered for patients with progressive disease, when other therapeutic strategies cannot be applied. Lenvatinib is a tyrosine kinase inhibitor targeting multiple molecular factors involved in angiogenesis and tumor progression. Preclinical studies have demonstrated the utility of lenvatinib as a targeted therapy for different tumors, including both differentiated and anaplastic thyroid cancer.Areas covered: The authors provide an overview of the preclinical development of lenvatinib in the treatment of thyroid cancer and review its clinical application. They also provide their expert opinion on its development.Expert opinion: Preclinical studies have helped in the understanding of the mechanisms of thyroid carcinogenesis and in the development of a targeted therapy. These findings have represented the rationale for the use of lenvatinib in clinical trials, which have confirmed its utility but yet failed to prove a clear benefit in overall survival. The decision to start a systemic treatment with lenvatinib must be personalized for each patient evaluating the risk/benefits ratio. Treatment emergent adverse events must be considered and reasonably managed by a multidisciplinary approach.

Radioactive Iodine-Refractory Differentiated Thyroid Cancer and Redifferentiation Therapy

The retained functionality of the sodium iodide symporter (NIS) expressed in differentiated thyroid cancer (DTC) cells allows the further utilization of post-surgical radioactive iodine (RAI) therapy, which is an effective treatment for reducing the risk of recurrence, and even the mortality, of DTC. Whereas, the dedifferentiation of DTC could influence the expression of functional NIS, thereby reducing the efficacy of RAI therapy in advanced DTC. Genetic alternations (such as BRAF and the rearranged during transfection [RET]/papillary thyroid cancer [PTC] rearrangement) have been widely reported to be prominently responsible for the onset, progression, and dedifferentiation of PTC, mainly through activating the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) signaling cascades. These genetic alternations have been suggested to associate with the reduced expression of iodide-handling genes in thyroid cancer, especially the NIS gene, disabling iodine uptake and causing resistance to RAI therapy. Recently, novel and promising approaches aiming at various targets have been attempted to restore the expression of these iodine-metabolizing genes and enhance iodine uptake through in vitro studies and studies of RAI-refractory (RAIR)-DTC patients. In this review, we discuss the regulation of NIS, known mechanisms of dedifferentiation including the MAPK and PI3K pathways, and the current status of redifferentiation therapy for RAIR-DTC patients.

MiR-4500 Regulates PLXNC1 and Inhibits Papillary Thyroid Cancer Progression

Although most patients with papillary thyroid cancer (PTC) are curable, there are still a few patients showing poor outcomes and increased risk of secondary cancers after therapies. In this study, we aimed to investigate the correlation between miR-4500 and PTC and to explore its molecular functions. A total of 50 patients were included, and sonography and histological examinations were used for diagnosis. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied for detection of mRNA levels while Western blotting was used for measuring protein expression. Cell proliferation was tested using CCK-8 and colony formation assays. Caspase-3 activity and nucleosomal fragmentation assays were employed to test cell apoptosis. Cell invasive ability was measured using transwell assay. MiR-4500 target was identified using luciferase assay and RNA pull-down assay. MiR-4500 expression was significantly decreased in five PTC cell lines compared with Nthy-ori 3-1 cells and in PTC tissues compared with adjacent normal thyroid tissues, respectively. Decreased expression of miR-4500 showed lower survival rate, higher cancer stage, and lymphatic metastasis. Therefore, our results implied that miR-4500 could serve as a potential biomarker for PTC prognosis. Overexpression of miR-4500 repressed colony formation, proliferation, and invasiveness of PTC cells whereas increased cell apoptosis. We identified that PLXNC1 was a direct target of miR-4500. PLXNC1 knockdown showed similar effects on cell viability, colony formation, and cell apoptosis as overexpression of miR-4500 in PTC cells. In conclusion, miR-4500 inhibits the malignant transformation of PTC cells by directly targeting and repressing PLXNC1.

Evaluation of prognostic usefulness of long noncoding RNA GAS5 and FAL1 in papillary thyroid carcinoma

Genetic studies on cancers have revealed that lncRNA-GAS5 and lncRNA-FAL1 are overexpressed in some cancerous cells. The aim of the present investigation was to evaluate the roles of lncRNA-GAS5 and lncRNA-FAL1 gene expression changes in the diagnosis and prognosis of patients with papillary thyroid carcinoma (PTC). In a case-control investigation, we recruited a total of 140 formalin-fixed paraffin-embedded tissues of PTC, including 70 cancerous and noncancerous tissues. Quantitative real-time polymerase chain reaction was used to determine the lncRNA-GAS5 and lncRNA-FAL1 level of gene expression in the two tissue groups. The association between the clinicopathological characteristics of patients and the expression level of lncRNA-GAS5 and lncRNA-FAL1 was evaluated. Our findings revealed that the level of expression in the lncRNA-GAS5 and lncRNA-FAL1 genes was significantly upregulated in thyroid cancerous tissues (P < 0.003 and P < 0.040, respectively). The expression of lncRNA-GAS5 and lncRNA-FAL1 revealed a significant association with tumor node metastasis staging (P < 0.042 and P < 0.001, respectively). It seems that the lncRNA-GAS5 and lncRNA-FAL1 genes play an oncogenic role in PTC. The two genes have a significant potential prognostic value and may likely be used as novel therapeutic targets for PTC patients in the future.

MiRNAs Are Involved in Tall Cell Morphology in Papillary Thyroid Carcinoma

Five percent of papillary thyroid carcinomas (PTC) show an adverse clinical outcome (ACO). The tall cell variant of papillary thyroid carcinomas (TCV) is a good predictor of an ACO, however, the identification of tall-cells is subjective. Micro RNAs are short non-coding ribonucleic acids (miRNA). Their expression in PTC could be a powerful, more objective predictor of prognosis.

METHODS

Forty-four PTC underwent miRNA profiling, twenty-four of them were TCV. The miRNA dataset was validated by analysis of expression of known target proteins (vascular endothelial growth factor (VEGF) and phosphatase and tensin homolog (PTEN)) in 125 patients including 48 TCV and 57 with an ACO.

RESULTS

One hundred and forty-nine miRNAs were significantly associated with an ACO, seventy-one of them with TC-morphology. Twenty-two miRNAs were identified as targets for VEGF and thirty-two as targets for PTEN. In univariate and multivariable analysis, reduced expression of PTEN and an increased expression of VEGF were associated with shorter relapse free survival. A classifier, including TC-morphology, pT-stage, VEGF, and PTEN, predicted relapse with an 80% accuracy.

CONCLUSIONS

Some miRNAs predict outcome in PTC and are involved in TC-morphology in PTC. These miRNAs may serve as more objective indicators of an ACO than tall cell morphology. PTEN and VEGF protein expression are prognostically relevant and are at least partially regulated by miRNAs.

Preoperative serum VEGF-C but not VEGF-A level is correlated with lateral neck metastasis in papillary thyroid carcinoma

BACKGROUND

This study aimed to investigate the relationships between serum vascular endothelial growth factor (VEGF)-A or VEGF-C levels and lymph node metastasis (LNM) status in patients with papillary thyroid carcinoma (PTC).

METHODS

The study enrolled 150 patients with pathologically proven PTC who underwent surgery: PTC without LNM, PTC with central neck metastasis, and PTC with lateral neck metastasis.

RESULTS

Preoperative serum VEGF-A levels were 300.12 ± 80.80 pg/mL overall and were not correlated with the presence of LNM. Preoperative serum VEGF-C levels were 132.41 ± 48.48 pg/mL overall and were significantly correlated with the presence of LNM. Serum VEGF-C levels were further increased in patients with lateral neck metastasis and positively correlated with the number of metastatic LNs (rho = 0.252, P = 0.002). Serum VEGF-C, but not VEGF-A, was identified as a significant predictor of lateral neck metastasis.

CONCLUSION

Serum VEGF-C might be a clinically relevant biomarker of lateral neck metastasis in patients with PTC.

Coding Molecular Determinants of Thyroid Cancer Development and Progression

Thyroid cancer is the most common endocrine malignancy. Its incidence and mortality rates have increased for patients with advanced-stage papillary thyroid cancer. The characterization of the molecular pathways essential in thyroid cancer initiation and progression has made huge progress, underlining the role of intracellular signaling to promote clonal evolution, dedifferentiation, metastasis, and drug resistance. The discovery of genetic alterations that include mutations (BRAF, hTERT), translocations, deletions (eg, 9p), and copy-number gain (eg, 1q) has provided new biological insights with clinical applications. Understanding how molecular pathways interplay is one of the key strategies to develop new therapeutic treatments and improve prognosis.

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.

Predictive Value of BRAFV600E Mutation for Lymph Node Metastasis in Papillary Thyroid Cancer: A Meta-analysis

BRAF^V600E mutation has been thought to be a valuable molecular marker that may predict a worse prognosis for papillary thyroid cancer (PTC). But whether BRAF^V600E mutation is associated with lymph node metastasis (LNM) remains controversial. Different surgical strategies may bring a bias in demonsstrating the association between them. In order to delineate a risk stratification to guide a tailored initial approach to tumors that express BRAF^V600E mutation, we performed this meta-analysis by using the articles in which total or near-total thyroidectomy plus bilateral central lymph node dissection was routinely performed to avoid the bias from the surgical strategy. We searched the Medline, Embase and CNKI database for eligible studies from January 2003 to May 2018. Meta-analysis was performed using the STATA 12.0 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated under fixed-effects or randomeffects models. Fifteen clinical studies were included with a total of 4909 PTC patients. Our meta-analysis results reported that BRAFV600E mutation was associated with LNM (OR=1.34; 95% CI: 1.09-1.65; P=0.005), as well as central LNM (OR=1.59; 95% CI: 1.35-1.88; P<0.00001). Moreover, in patients with papillary thyroid microcarcinoma, we also confirmed the predictive value of BRAF^V600E mutation for LNM (OR=3.49; 95% CI: 2.02-6.02; P<0.00001). This meta-analysis demonstrates that BRAF^V600E mutation is closely related to LNM in PTC patients. The results suggest that BRAF^V600E mutation can be considered as a risk factor for LNM in PTC. Moreover, combining BRAF^V600E mutation with other risk factors to determine the initial surgical treatment may bring benefits for PTC patients.

Targeted next-generation sequencing of cancer-related genes in thyroid carcinoma: A single institution's experience

Thyroid carcinoma (TC) has characteristic genetic alterations, including point mutations in proto-oncogenes and chromosomal rearrangements that vary by histologic subtype. Recent developments in next-generation sequencing (NGS) technology enable simultaneous analysis of cancer-associated genes of interest, thus improving diagnostic accuracy and allowing precise personalized treatment for human cancer. A total of 50 patients who underwent thyroidectomy between 2014 and 2016 at Hokuto Hospital were enrolled. Total DNA was extracted from formalin-fixed, paraffin-embedded tissue sections and quantified. Targeted regions of 24 cancer-associated genes were amplified by PCR, barcoded and sequenced using an Illumina MiSeq platform. Subjects included 30 patients with papillary carcinoma (PC), two with PC tall cell variant (TVPC), two with PC follicular variant (FVPC), eight with follicular carcinoma, seven with poorly differentiated carcinoma (PDC), and one with anaplastic carcinoma (AC). The BRAF V600E mutation was present in 25 of 30 (83%) patients with PC, 2 of 2 (100%) patients with TVPC, 6 of 7 (86%) patients of PDC, and one patient with AC. PIK3CA mutations were present in 3 of 30 (delPV104P, A1046T and C420R; 10%) patients with PC and 1 of 7 (H1047R; 14%) patients with PDC. The TP53 mutation was present in 1 of 30 (R306*; 3.3%) patients with PC and 1 of 7 (Q152*; 14%) patients with PDC. The NRAS mutation was present in 1 of 2 (Q61K, 50%) patients with FVPC. Statistical analysis showed that patients without the BRAF V600E mutation had advanced pathologic T and N stages compared with those with the mutation (P=0.047 and P=0.019, respectively). The BRAF V600E mutation was not correlated with overall and disease-free survival in patients with PC. A patient with PC with a mutation in EGFR (K852Q) and the PIK3CA mutation had an aggressive course with multiple bone and lung metastases. Detection of mutations in cancer-associated genes using NGS could enhance the understanding of the clinical behavior of TC.

False-negative BRAF V600E mutation results on fine-needle aspiration cytology of papillary thyroid carcinoma

BACKGROUND

The BRAF V600E mutation is highly specific for papillary thyroid carcinoma (PTC). A test for this mutation can increase the diagnostic accuracy of fine-needle aspiration cytology (FNAC), but a considerably high false-negative rate for the BRAF V600E mutation on FNAC has been reported. In this study, we investigated the risk factors associated with false-negative BRAF V600E mutation results on FNAC.

METHODS

BRAF V600E mutation results of 221 PTC nodules between December 2011 and June 2013 were retrospectively reviewed. BRAF V600E mutation results on both preoperative FNAC and postoperative formalin-fixed, paraffin-embedded (FFPE) samples were compared. We investigated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of BRAF V600E mutation results on FNAC. And, we identified the risk factors associated with false-negative results.

RESULTS

Of 221 PTC nodules, 150 (67.9%) on FNAC and 185 (83.7%) on FFPE samples were BRAF V600E mutation positive. The sensitivity, specificity, PPV, and NPV for BRAF V600E mutation testing with FNAC were 80.5, 97.2, 99.3, and 49.3%, respectively. Thirty-six (16.3%) BRAF V600E mutation-negative nodules on FNAC were mutation positive on FFPE sample analysis. Risk factors for these false-negative results were age, indeterminate FNAC results (nondiagnostic, atypia of undetermined significance (AUS), and findings suspicious for PTC), and PTC subtype.

CONCLUSION

False-negative rate of BRAF mutation testing with FNAC for thyroid nodules is increased in cases of old age, indeterminate FNAC pathology results, and certain PTC subtypes. Therapeutic surgery can be considered for these cases. A well-designed prospective study with informed consent of patients will be essential for more informative results.

Galectin-3 Performance in Histologic a Cytologic Assessment of Thyroid Nodules: A Systematic Review and Meta-Analysis

The literature on Galectin-3 (Gal-3) was systematically reviewed to achieve more robust information on its histologic reliability in identifying thyroid cancers and on the concordance between Gal-3 test in histologic and cytologic samples. A computer search of the PubMed and Scopus databases was conducted by combinations of the terms thyroid and Gal-3. Initially, 545 articles were found and, after their critical review, 52 original papers were finally included. They reported 8172 nodules with histologic evaluation of Gal-3, of which 358 with also preoperative FNAC Gal-3 assessment. At histology, Gal-3 sensitivity was 87% (95% confidence intervals [CI] from 86% to 88%), and specificity 87% (95% CI from 86% to 88%); in both cases, we found heterogeneity (I₂ 85% and 93%, respectively) and significant publication bias (p < 0.001). The pooled rate of positive Gal-3 at fine needle aspiration (FNAC) among cancers with histologically proven Gal-3 positivity was 94% (95% CI from 89% to 97%), with neither heterogeneity (I₂ 14.5%) nor bias (p = 0.086). These data show high reliability of Gal-3 for thyroid cancer at histology, while its sensitivity on FNAC samples is lower. The limits of cytologic preparations and interpretation of Gal-3 results have to be solved.

Current Standards in Treatment of Radioiodine Refractory Thyroid Cancer

OPINION STATEMENT

Radioiodine refractory differentiated thyroid cancer (RAI-R DTC) is a challenging malignancy with limited prognosis and treatment options. Recently, clinical trials with targeted therapies have advanced the outlook of these patients, and inhibition of the vascular endothelial growth factor (VEGF) axis has led to the approval of small-molecule tyrosine kinase inhibitors (TKIs) for first-line treatment of radioiodine refractory disease. In addition to approved therapies (sorafenib and lenvatinib), other multi-targeted tyrosine kinase inhibitors that are commercially available have been recognized as viable treatment options for RAI-R DTC. Our preference is to initially use lenvatinib, given the dramatic progression-free survival (PFS) improvement versus placebo, with the caveat that 24 mg daily is not often tolerated and lower doses often used. In patients with BRAF V600E mutation, BRAF inhibitors are now considered for treatment, especially if patients are at high risk from antiangiogenic therapy. Research is continuing to evolve in identifying mechanisms related to radioiodine refractoriness, and trials are evaluating therapeutic molecules to overcome this resistance. Clinical care of patients with RAI-R DTC requires careful consideration of both patient and disease characteristics. Many patients with asymptomatic and indolent disease can be followed for years without treatment while others with high volume or rapidly progressive disease merit early intervention.

Growth arrest by activated BRAF and MEK inhibition in human anaplastic thyroid cancer cells

Anaplastic thyroid cancer (ATC) is a rare malignancy that progresses extremely aggressively and often results in dismal prognosis. We investigated the efficacy of inhibiting the activated RAS/RAF/MEK pathway in ATC cells aiming to clarify the mechanism of effect and resistance. Four human ATC cell lines (ACT-1, OCUT-2, OCUT-4 and OCUT-6) were used. OCUT-4 had a BRAF mutation. OCUT-2 had both BRAF and PI3KCA mutations. ACT-1 and OCUT-6 had wild-type BRAF and NRAS mutations. The effects of dabrafenib, a selective inhibitor of the BRAFV600E kinase, and trametinib, a reversible inhibitor of MEK activity, were investigated. Dabrafenib strongly inhibited the viability in BRAF mutated cells by demonstrating G0/G1-arrest via the downregulation of MEK/ERK phosphorylation. Upregulated phosphorylation of MEK was observed in RAS mutated cells after dabrafenib treatment and caused VEGF upregulation, but was not related to the cellular proliferation. Trametinib inhibited the cellular viability to variable degrees in every cell by downregulating ERK phosphorylation. Dual blockade by both inhibitors demonstrated clear cytostatic effect in all the cells. OCUT-4 showed the weakest sensitivity to trametinib, no additional effect of either inhibitor in combination with the other, and an increase of SNAI1 mRNA expression after treatment with inhibitors, suggesting a mechanism for resistance. Our findings demonstrated the efficacy of a mutation-selective BRAF inhibitor and a MEK inhibitor in human ATC cells in a genetic alteration-specific manner.

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

Background

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

Methods

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

Results

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

Conclusions

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

Activity and Safety of Sunitinib in Patients with Advanced Radioiodine Refractory Thyroid Carcinoma: A Retrospective Analysis of 57 Patients

BACKGROUND

The aim of this study was to evaluate the effectiveness of sunitinib in patients with progressive radioiodine refractory (RAIR) thyroid cancer (TC).

MATERIALS AND METHODS

A multicentric retrospective analysis was performed of patients treated in six TUmeurs THYroïdiennes REFractaires participating centers. All patients with progressive RAIR TC who were treated with sunitinib outside a clinical trial between August 2007 and March 2015 were retrospectively and consecutively included. The primary endpoint was the overall response rate (ORR) and disease control rate ≥6 months based on RECIST criteria. Secondary endpoints included evaluation of overall survival (OS) and progression-free survival (PFS) from the first dose of sunitinib. Primary and secondary endpoints were also evaluated according to treatment setting: first or second line of tyrosine kinase inhibitor (TKI).

RESULTS

Fifty-seven patients (29 men; 50.8%), mean age 62.2 years (range 43-80 years) with progressive RAIR TC were included. Sunitinib was the first-line TKI treatment for 32 (56.1%) patients and the second-line TKI treatment for 25 (43.9%) patients. For all patients, according to RECIST criteria, ORR was 35.1% (20 patients) and disease control rate ≥6 months was 68.4% (39 patients). No complete response was observed. Six (10.5%) patients showed disease progression. When sunitinib was used as first-line TKI therapy, ORR was 46.9% (15/32 patients), and disease control rate ≥6 months was 75% (24/32 patients). When sunitinib was used as second-line TKI therapy, ORR was 20% (5/25 patients), and disease control rate ≥6 months was 60% (15/25 patients). The median OS and PFS were 21.0 (range 15-29) and 10.2 months (range 6-13), respectively, for all patients. With sunitinib as first-line TKI-therapy, median OS and PFS was 30.0 (range 19.0-53.0) and 15 (range 7.0-21.0) months, respectively. As second-line therapy, median OS and PFS were 13 (range 8.0-20.0) and 6 (range 5.0-11.0) months, respectively. Eleven (19.3%) patients experienced grade 3 toxicity, and four patients (7.0%) experienced grade 4 toxicity.

CONCLUSION

The efficacy of sunitinib as first- and second-line TKI therapy in a large cohort of patients treated for progressive RAIR TC is herein reported. Further prospective studies are needed to evaluate the effectiveness of sunitinib in RAIR TC.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Treatment of advanced thyroid cancer with targeted therapies: ten years of experience

Thyroid cancer is rare, but it is the most frequent endocrine malignancy. Its prognosis is generally favorable, especially in cases of well-differentiated thyroid cancers (DTCs), such as papillary and follicular cancers, which have survival rates of approximately 95% at 40 years. However, 15-20% of cases became radioiodine refractory (RAI-R), and until now, no other treatments have been effective. The same problems are found in cases of poorly differentiated (PDTC) and anaplastic (ATC) thyroid cancers and in at least 30% of medullary thyroid cancer (MTC) cases, which are very aggressive and not sensitive to radioiodine. Tyrosine kinase inhibitors (TKIs) represent a new approach to the treatment of advanced cases of RAI-R DTC, MTC, PDTC, and, possibly, ATC. In the past 10 years, several TKIs have been tested for the treatment of advanced, progressive, and RAI-R thyroid tumors, and some of them have been recently approved for use in clinical practice: sorafenib and lenvatinib for DTC and PDTC and vandetanib and cabozantinib for MTC. The objective of this review is to present the current status of the treatment of advanced thyroid cancer with the use of innovative targeted therapies by describing both the benefits and the limits of their use based on the experiences reported so far. A comprehensive analysis and description of the molecular basis of these therapies, as well as new therapeutic perspectives, are reported. Some practical suggestions are given for both the choice of patients to be treated and their management, with particular regard to the potential side effects.

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.

MicroRNA-3151 inactivates TP53 in BRAF-mutated human malignancies

The B-Raf proto-oncogene serine/threonine kinase (BRAF) gene is the most frequently mutated gene in malignant melanoma (MM) and papillary thyroid cancer (PTC) and is causally involved in malignant cell transformation. Mutated BRAF is associated with an aggressive disease phenotype, thus making it a top candidate for targeted treatment strategies in MM and PTC. We show that BRAF mutations in both MM and PTC drive increased expression of oncomiR-3151, which is coactivated by the SP1/NF-κB complex. Knockdown of microRNA-3151 (miR-3151) with short hairpin RNAs reduces cell proliferation and increases apoptosis of MM and PTC cells. Using a targeted RNA sequencing approach, we mechanistically determined that miR-3151 directly targets TP53 and other members of the TP53 pathway. Reducing miR-3151's abundance increases TP53's mRNA and protein expression and favors its nuclear localization. Consequently, knockdown of miR-3151 also leads to caspase-3-dependent apoptosis. Simultaneous inhibition of aberrantly activated BRAF and knockdown of miR-3151 potentiates the effects of sole BRAF inhibition with the BRAF inhibitor vemurafenib and may provide a novel targeted therapeutic approach in BRAF-mutated MM and PTC patients. In conclusion, we identify miR-3151 as a previously unidentified player in MM and PTC pathogenesis, which is driven by BRAF-dependent and BRAF-independent mechanisms. Characterization of TP53 as a downstream effector of miR-3151 provides evidence for a causal link between BRAF mutations and TP53 inactivation.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Mutation Profile of Well-Differentiated Thyroid Cancer in Asians

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

Association Between Obesity and BRAFV600E Mutation Status in Patients with Papillary Thyroid Cancer

BACKGROUND

The prevalence of papillary thyroid cancer (PTC) is thought to be related to obesity, which affects the prognosis for PTC patients. However, the mechanisms implicated in the relationship between obesity and PTC is a matter for debate. In this study, we aimed to gain insight into the relationship between obesity and the clinicopathological features of PTC, including the BRAFV600E mutation.

METHODS

The medical records of 1121 PTC patients were reviewed and the relationships between anthropometric factors, biochemical parameters, and clinicopathological parameters, including BRAFV600E mutation status, were analyzed.

RESULTS

Body mass index (BMI) showed a strong association with advanced TNM stage (p < 0.001) and BRAFV600E mutation status (p = 0.008). We also found that BRAFV600E (+) patients had a higher body weight (p = 0.024) and a higher BMI (p = 0.003) than patients with BRAFV600E (-) PTC. In addition, BRAFV600E (+) PTC patients had a significantly higher incidence of extrathyroidal extension (p = 0.025) and more advanced T, N, TNM stage (p < 0.001) than BRAFV600E (-) PTC patients. Consistent with this observation, female BRAFV600E (+) PTC patients had a higher BMI (p = 0.011) and more aggressive tumor behaviors than female BRAFV600E (-) PTC patients. In multivariate analysis, BMI was persistently associated with BRAFV600E mutation in the entire cohort (odds ratio [OR] 1.387; 95 % CI 1.036-1.859; p = 0.028) and in the female subcohort (OR 1.221; 95 % CI 1.014-1.631; p = 0.046).

CONCLUSION

The positive association between BMI and BRAFV600E supports the hypothesis that excessive bodyweight influences tumor progression.

Expression of angiogenic switch, cachexia and inflammation factors at the crossroad in undifferentiated thyroid carcinoma with BRAF(V600E)

Cachexia is the result of complex metabolic alterations which cause morbidity and mortality in patients with advanced cancers including undifferentiated (anaplastic) thyroid carcinoma (ATC). ATC is a lethal disease with limited therapeutic options and unclear etiology for cachexia. We hypothesize that the BRAF(V600E) oncoprotein triggers microvascular endothelial cell tubule formation (in vitro angiogenesis) by means of factors which play a crucial role in angiogenic switch, inflammation/immune response and cachexia. We use human ATC cells and applied multiplex ELISA assay to screen for and measure angiogenic/cachectic and pro-inflammatory factors in the ATC-derived secretome. We find that vemurafenib anti-BRAF(V600E) therapy significantly reduces secreted VEGFA, VEGFC and IL6 protein levels compared to vehicle-treated ATC cells. As a result, the secretome from vemurafenib-treated ATC cells inhibits microvascular endothelial cell-related in vitro angiogenesis. Furthermore, ATC clinical samples express VEGFA, VEGFC and IL6 proteins. Our results suggest that angiogenic/cachectic and pro-inflammatory/immune response factors could play a crucial role in BRAF(V600E)-positive human ATC aggressiveness. Understanding the extent to which microenvironment-associated angiogenic factors participate in cachexia and cancer metabolism in advanced thyroid cancers will reveal new biomarkers and foster novel therapeutic approaches.

GLI1 Transcription Factor Affects Tumor Aggressiveness in Patients With Papillary Thyroid Cancers

A significant proportion of patients with papillary thyroid cancer (PTC) present with extrathyroidal extension (ETE) and lymph node metastasis (LNM). However, the molecular mechanism of tumor invasiveness in PTC remains to be elucidated. The aim of this study is to understand the role of Hedgehog (Hh) signaling in tumor aggressiveness in patients with PTC. Subjects were patients who underwent thyroidectomy from 2012 to 2013 in a single institution. Frozen or paraffin-embedded tumor tissues with contralateral-matched normal thyroid tissues were collected. Hh signaling activity was analyzed by quantitative RT-PCR (qRT-PCR) and immunohistochemical (IHC) staining. Datasets from Gene Expression Omnibus (GEO) (National Center for Biotechnology Information) were subjected to Gene Set Enrichment Analysis (GSEA). BRAFT1799A and telomerase reverse transcriptase promoter mutation C228T were analyzed by direct sequencing. Among 137 patients with PTC, glioma-associated oncogene homolog 1 (GLI1) group III (patients in whom the ratio of GLI1 messenger ribonucleic acid (mRNA) level in tumor tissue to GLI1 mRNA level in matched normal tissue was in the upper third of the subject population) had elevated risk for ETE (odds ratio [OR] 4.381, 95% confidence interval [CI] 1.414-13.569, P = 0.01) and LNM (OR 5.627, 95% CI 1.674-18.913, P = 0.005). Glioma-associated oncogene homolog 2 (GLI2) group III also had elevated risk for ETE (OR 4.152, 95% CI 1.292-13.342, P = 0.017) and LNM (OR 3.924, 95% CI 1.097-14.042, P = 0.036). GSEA suggested that higher GLI1 expression is associated with expression of the KEGG gene set related to axon guidance (P = 0.031, false discovery rate < 0.05), as verified by qRT-PCR and IHC staining in our subjects.GLI1 and GLI2 expressions were clearly related to aggressive clinicopathological features and aberrant activation of GLI1 involved in the axon guidance pathway. These results may contribute to development of new prognostic markers, as well as novel therapeutic targets.

When thyroid carcinoma goes bad: a morphological and molecular analysis

Thyroid carcinomas of follicular epithelial derivation are common and generally well-behaved malignancies with excellent cure and survival rates. However, a subset of these carcinomas, whether well-differentiated, poorly differentiated, or anaplastic, is highly aggressive, manifesting with local invasion, recurrence, and distant metastasis. The recognition of dedifferentiation is of paramount importance. In addition, the challenge for Pathologists is to identify the rare aggressive differentiated carcinomas so that treatment may be tailored appropriately. Thus, histological subtyping and documentation of other aggressive features such as widespread invasion and angioinvasion are critical. Mutational analyses in the past decade have delineated the molecular alterations responsible for thyroid carcinogenesis and progression, allowing greater sub-classification and prognostication of thyroid carcinomas. This review article highlights important aggressive morphologic features and molecular mutations associated with thyroid carcinoma.

Differentiated thyroid cancer: focus on emerging treatments for radioactive iodine-refractory patients

BACKGROUND

The treatment of differentiated thyroid cancer refractory to radioactive iodine (RAI) had been hampered by few effective therapies. Recently, tyrosine kinase inhibitors (TKIs) have shown activity in this disease. Clinical guidance on the use of these agents in RAI-refractory thyroid cancer is warranted.

MATERIALS AND METHODS

Molecular mutations found in RAI-refractory thyroid cancer are summarized. Recent phase II and III clinical trial data for TKIs axitinib, lenvatinib, motesanib, pazopanib, sorafenib, sunitinib, and vandetinib are reviewed including efficacy and side effect profiles. Molecular targets and potencies of these agents are compared. Inhibitors of BRAF, mammalian target of rapamycin, and MEK are considered.

RESULTS

Routine testing for molecular alterations prior to therapy is not yet recommended. TKIs produce progression-free survival of approximately 1 year (range: 7.7-19.6 months) and partial response rates of up to 50% by Response Evaluation Criteria in Solid Tumors. Pazopanib and lenvatinib are the most active agents. The majority of patients experienced tumor shrinkage with TKIs. Common adverse toxicities affect dermatologic, gastrointestinal, and cardiovascular systems.

CONCLUSION

Multiple TKIs have activity in RAI-refractory differentiated thyroid cancer. Selection of a targeted agent should depend on disease trajectory, side effect profile, and goals of therapy.

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

BACKGROUND

Over the past several decades, there has been a rapid worldwide increase in the prevalence of papillary thyroid cancer (PTC) as well as a number of changes in the clinicopathological characteristics of this disease. BRAF(V600E), which is a mutation of the proto-oncogene BRAF, has become the most frequent genetic mutation associated with PTC, particularly in Korea. Thus, the present study investigated whether the prevalence of the BRAF(V600E) mutation has increased over the past two decades in the Korean population and whether various PTC-related clinicopathological characteristics have changed.

METHODS

The present study included 2,624 patients who underwent a thyroidectomy for PTC during two preselected periods; 1995 to 2003 and 2009 to 2012. The BRAF(V600E) mutation status of each patient was confirmed using the polymerase chain reaction-restriction fragment length polymorphism method or by the direct sequencing of DNA.

RESULTS

The prevalence of the BRAF(V600E) mutation in Korean PTC patients increased from 62.2% to 73.7% (P=0.001) over the last two decades. Additionally, there was a greater degree of extrathyroidal extension (ETE) and lymph node metastasis in 2009 to 2012 patients with the BRAF(V600E) mutation and a higher frequency of thyroiditis and follicular variant-PTC in 2009 to 2012 patients with wild-type BRAF. However, only the frequency of ETE was significantly higher in 1995 to 2003 patients with the BRAF(V600E) mutation (P=0.047). Long-term recurrence rates during a 10-year median follow-up did not differ based on BRAF(V600E) mutation status.

CONCLUSION

The BRAF(V600E) mutation rate in Korean PTC patients has been persistently high (approximately 70%) over the past two decades and continues to increase. The present findings demonstrate that BRAF(V600E)-positive PTC was associated with more aggressive clinicopathological features, especially in patients who were recently diagnosed, suggesting that BRAF(V600E) mutation status may be a useful prognostic factor for PTC in patients recently diagnosed with this disease.

BRAF gene: From human cancers to developmental syndromes

The BRAF gene encodes for a serine/threonine protein kinase that participates in the MAPK/ERK signalling pathway and plays a vital role in cancers and developmental syndromes (RASopathies). The current review discusses the clinical significance of the BRAF gene and other members of RAS/RAF cascade in human cancers and RAS/MAPK syndromes, and focuses the molecular basis and clinical genetics of BRAF to better understand its parallel involvement in both tumourigenesis and RAS/MAPK syndromes—Noonan syndrome, cardio-facio-cutaneous syndrome and LEOPARD syndrome.

Associations of the BRAF(V600E) mutation with sonographic features and clinicopathologic characteristics in a large population with conventional papillary thyroid carcinoma

OBJECTIVE

To evaluate the association of the BRAF(V600E) mutation with sonographic features and clinicopathologic characteristics in a large population with conventional papillary thyroid carcinoma (PTC).

METHODS

We retrospectively reviewed the sonographic features, clinicopathologic characteristics, and presence of the BRAF(V600E) mutation in 688 patients who underwent thyroidectomy for conventional PTC between January and July 2010 at a single institution. The incidence of the BRAF(V600E) mutation was calculated. The sonographic features and clinicopathologic characteristics were compared between BRAF-positive and BRAF-negative patients. BRAF-positive patients were subdivided into those with papillary thyroid microcarcinoma (the PTMC group) and those with PTC larger than 10 mm (the PTC>10 mm group), and their sonographic features were compared.

RESULTS

The BRAF(V600E) mutation was detected in 69.2% of patients (476 of 688). Sonographic features were not significantly different between BRAF-positive and BRAF-negative PTC, nor between PTMC and PTC>10 mm groups. The BRAF(V600E) mutation was associated with male sex (P = 0.028), large tumor size, extrathyroidal extension, central and lateral lymph node metastasis, and advanced tumor stage (P<0.0001).

CONCLUSION

The BRAF(V600E)mutation was significantly associated with several poor clinicopathologic characteristics, but was not associated with sonographic features, regardless of tumor size. We recommend that patients with a thyroid nodule with any suspicious sonographic feature undergo preoperative BRAF(V600E) testing for risk stratification and to guide the initial surgical approach in PTC.

Up-regulation of urinary-type plasminogen activator correlates with high-risk papillary thyroid carcinoma with BRAF(V600E) mutation and its possible molecular mechanism

The aim of the present study is to investigate the relationship between urinary-type plasminogen activator (uPA) expression and clinicopathological features in papillary thyroid carcinoma (PTC) and to determine the signal transduction of PTC cells in vitro. PTC tissues from 42 patients were analyzed for the expression of uPA and the BRAF(V600E) mutation. BCPAP, a PTC cell line harboring the BRAF(V600E) mutation, was used to study MAPK signaling. PCR and direct sequencing were applied to analyze BRAF(V600E) mutation status. uPA mRNA expression was measured using a quantitative RT-PCR method, and uPA protein was localized using an immunohistochemical method. The ERK protein status was detected by Western blot analysis. uPA gene expression was significantly increased in PTC tissues as compared to the corresponding non-tumor tissues. Furthermore, the up-regulation of uPA mRNAs was correlated with high-risk clinicopathological features, including extrathyroid invasion, loss of cellular polarity/cohesiveness, and the BRAF(V600E) mutation. Marked dephosphorylation of ERK1/2 and down-regulation of uPA expression were detected when BCPAP was treated with a MEK inhibitor, U0126. MEK inhibitors might be a potential treatment strategy for aggressive PTC with BRAF(V600E) through inhibition of uPA expression.