Thyroid cancer: molecular aspects and new therapeutic strategies

Update on iodine-refractory differentiated thyroid carcinoma

Radioiodine therapy represents a fundamental pillar in the routine adjuvant therapy of patients with high-risk differentiated thyroid carcinoma. However, a non-negligible percentage of these patients will develop iodine refractoriness, showing a worse prognosis, as well a lower survival, which demonstrates a clear need to explore different therapeutic approaches. Iodine refractory patient treatment continues to be a challenge, currently having different novel therapeutic options that should be known by the different specialties related to differentiated thyroid carcinoma (DTC). The aim of this work is to review iodine refractory thyroid carcinoma treatment, focusing especially on the definition of iodine refractoriness, highlighting its importance due to its high mortality, and introducing the different therapeutic options available for these patients.

Changes in peripheral blood immune cell population in thyroid cancer patients treated with lenvatinib

This study evaluated changes in the peripheral blood immune cell population in patients with advanced thyroid cancer receiving lenvatinib treatment to confirm the immune-modulatory effect of lenvatinib. After obtaining informed consent from patients, we prospectively collected 20 ml of whole blood at 2-3 months intervals 2-4 times from each patient; peripheral blood mononuclear cells (PBMCs) were separated, and the Maxpar Direct Immune Profiling Assay was performed. A total of 10 patients were enrolled, and 31 blood samples were obtained. The median age of patients was 65 years, and all patients showed durable responses to the lenvatinib treatment. When we compared the PBMC profiles between the pre-treatment, on-treatment, and off-treatment samples, the peripheral natural killer (NK) cell proportion differed significantly. The proportion of NK cells among total live cells significantly increased from 9.3 ± 4.5 (%) in the pre-treatment samples to 20.8 ± 7.9 (%) in the on-treatment samples (P = 0.009) and decreased to 13.3 ± 3.1 (%) in the off-treatment samples (P = 0.07). There was a significant increase in the peripheral NK cell population with lenvatinib treatment in advanced thyroid cancer patients. This finding confirms the immune-modulatory effect of lenvatinib.

The importance of hsa-miR-28 in human malignancies

MicroRNA production in tumorigenesis is dysregulated by a variety of processes, such as proliferation and removal of microRNA genes, aberrant transcriptional regulation of microRNAs, disrupted epigenetic alterations, and failures in the miRNA biogenesis machinery. Under some circumstances, miRNAs may act as tumorigenic and maybe anti-oncogenes. Tumor aspects such as maintaining proliferating signals, bypassing development suppressors, delaying apoptosis, stimulating metastasis and invasion, and promoting angiogenesis have been linked to dysfunctional and dysregulated miRNAs. MiRNAs have been found as possible biomarkers for human cancer in a great deal of research, which requires additional evaluation and confirmation. It is known that hsa-miR-28 can function as an oncogene or tumor suppressor in many malignancies, and it does this by modulating the expression of several genes and the downstream signaling network. MiR-28-5p and miR-28-3p, which originate from the same RNA hairpin precursor miR-28, have essential roles in a variety of cancers. This review outlines the function and mechanisms of miR-28-3p and miR-28-5p in human cancers and illustrates the miR-28 family's potential utility as a diagnostic biomarker for prognosis and early detection of cancers.

The expression of HDAC9 and P300 in papillary thyroid carcinoma cell line

PURPOSE

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer and accounts for 85-90% of all thyroid cancers. Metastatic differentiated thyroid cancer, radioiodine-refractory thyroid cancer, and anaplastic thyroid cancer still lack effective therapeutic options. Here, we aimed to assess HDAC9 and P300 expression in the papillary thyroid carcinoma cell line and compare them with normal thyroid cells.

METHODS

Nthy-ori-3-1, a normal thyroid cell line, and BCPAP, a PTC cell line, were cultured for 24 and 48 h and immunofluorescence staining was used to determine the levels of HDAC9 and P300 protein expression. HDAC9 paracrine release was assessed using an ELISA assay.

RESULTS

HDAC9 protein expression was higher in both cell groups at the 48th hour than at the 24th hour; however, P300 protein expression was lower in BCPAP cells at the 48th hour than at the 24th hour. In comparison to Nthy-ori-3-1, BCPAP expressed more HDAC9 and P300 proteins. HDAC9 secretion slightly increased in Nthy-ori-3-1 cells from 24 to 48 h. Furthermore, HDAC9 secretion in BCPAP cells dramatically decreased from 24 to 48 h.

CONCLUSION

Our findings revealed that the expression of HDAC9 and P300 was higher in the PTC cell line than in normal thyroid cells. This indicates that the acetylation mechanism in thyroid cancer cells is not the same as it is in healthy cells. Epigenetic studies may reveal the mechanisms underlying PTC with further analysis.

Anlotinib for Recurrent or Metastatic Primary Malignant Bone Tumor: A Multicenter, Single-Arm Trial

Objective

Anlotinib, a novel multitarget kinase inhibitor of VEGFR, FGFR, PDGFR and c-Kit, has proven to be effective and safe for refractory soft tissue sarcoma patients, but has not been examined in recurrent or metastatic primary malignant bone tumors in a clinical trial setting.

Methods

This is a multicenter single-arm trial. Patients with pathologically proven recurrent or metastatic primary malignant bone tumors were eligible. Anlotinib was administered orally at 12 mg per day. Each cycle consisted of 2 weeks of treatment followed by 1-week off-treatment. The primary endpoint was progression-free survival (PFS), as assessed in the intention-to-treat (ITT) population. Secondary endpoints included objective response rate (ORR), disease control rate (DCR) and overall survival (OS). Adverse events (AEs) were assessed per NCI CTCAE version 4.03.

Results

A total of 42 patients were enrolled. Median PFS was 5.3 months (95% CI 3.5-8.4 months) in the overall analysis, 4.8 months (95%CI 3.5-7.1 months) in osteosarcoma patients and 2.8 months [95%CI 1.3 months to not reached (NR)] in chondrosarcoma patients. The median OS was 11.4 months (95% CI 10.1 months to NR) in the overall analysis, not reached (95% CI, NR, NR) in osteosarcoma patients and 11.4 months (95% CI 1.8 to 21.1 months) in chondrosarcoma patients. The ORR was 9.52% and DCR was 78.57%. Grade 3 or above AEs occurred in 54.76% of the patients, and included hypertension (19.05%), hypertriglyceridemia (9.52%) and pustulosis palmaris et plantaris (7.14%). No treatment-related death was reported.

Conclusion

Anlotinib demonstrated promising antitumor activities in recurrent or metastatic primary malignant bone tumors with manageable AEs.

The role of microRNAs in the pathogenesis of thyroid cancer

Thyroid cancer is the most frequent type of cancers originating from the endocrine system. Early diagnosis leads to good clinical outcome in differentiated types of thyroid cancer. Yet, there are few treatment options for patients with medullary or anaplastic thyroid cancer. Thus, identification of molecular markers that explain the pathologic process during evolution of this cancer has practical significance. MicroRNAs (miRNAs) have been shown to influence the activity of thyroid cancer-related signaling pathways such as MAPK pathway and RET gene. These small transcripts not only can differentiate malignant tissues from non-malignant tissues, but also have differential expression in different stages of thyroid cancer. Assessment of serum levels of miRNAs is a practical noninvasive method for follow-up of patients after thyroidectomy. Moreover, the therapeutic effects of a number of miRNAs have been verified in xenograft models of thyroid cancer. In the current review, we summarize the data regarding the role of miRNAs in thyroid cancer.

NEOADJUVANT LENVATINIB IN ADVANCED UNRESECTABLE MEDULLARY THYROID CARCINOMA: A CASE REPORT

Objective

Medullary thyroid carcinoma, a rare form of thyroid cancer, is typically managed with surgical excision. However, in patients with locally-invasive tumors, an aggressive surgical attempt may result in unnecessary morbidity. Neoadjuvant tyrosine kinase inhibition has been utilized to downstage tumors prior to surgical excision but its role in thyroid cancer treatment is not well-established. We describe the potential role that lenvatinib, a tyrosine kinase inhibitor, may have as a neoadjuvant agent in advanced locoregional medullary thyroid carcinoma.

Methods

Our patient presented with a large left thyroid mass and bulky left lateral neck lymphadenopathy. Imaging studies revealed a hypervascular and locally-invasive tumor with metastatic central and left lateral lymphadenopathy. A lymph node biopsy cytologic evaluation and plasma calcitonin concentration of 32,926 pg/mL were consistent with medullary thyroid carcinoma. Rearranged during transfection germline mutation testing was negative. A multidisciplinary team of physicians deemed the patient a poor surgical candidate and recommended 4 months of neoadjuvant lenvatinib therapy to reduce tumor burden with a subsequent reassessment of resectability. Given the tumor's hypervascularity, lenvatinib was chosen due its potent vascular endothelial growth factor receptor inhibition, as well as its availability at our institution.

Results

Lenvatinib therapy resulted in rapid regression of tumor volume (approximately 70% reduction) as documented by computed tomography and ultrasound. Surgery after 4 months of treatment resulted in a 99% reduction in serum calcitonin and imaging studies 6 months later showed no residual disease.

Conclusion

Lenvatinib has potential as a neoadjuvant agent in advanced medullary thyroid carcinoma, and permitted tumor resection in this previously inoperable patient.

Diagnostic value of the candidate microRNAs in thyroid fine-needle aspiration biopsy (FNAB) samples

Background Thyroid cancer (TC) is known to be the most common endocrine malignancy with an incidence rate which has increased by 2.3-fold over the past 30 years. Approximately, 30% of the thyroid fine-needle aspiration biopsy (FNAB) outcomes are indecisive. Moreover, researchers recognized multiple differentially expressed microRNAs (miRNAs) as candidate diagnostic markers for thyroid nodules. The purpose of this study was to identify thyroid tumor-associated miRNAs in FNAB with the capacity to be developed as unique biomarkers. Materials and methods According to the study design, a quantitative real time reverse transcription polymerase chain reaction (qRT-PCR) was applied to evaluate the expression levels of nine miRNAs (Let7, miR-34a, miR-146b, miR-221, miR-151, miR-155, miR-181b, miR-222 and miR-375) among 224 FNA samples as the training set. Results The findings of this study revealed that miR-181b and miR-146b are the best predictors to diagnose benign thyroid FNA samples from malignant samples. However, the remaining miRNAs were co-expressed and had no significant effect on the predictor model. On the other hand, sensitivity and specificity of miR-181b and miR-146b were reported at 83.0%-83.0% and 83.0%-66.0%, respectively. Conclusions According to the results of this study, miR-146b and miR-181b might be considered as adjunct markers contributing to thyroid FNAB in tumor types. In addition, miR-146b and miR-181b were recognized as biomarkers for discriminating benign thyroid nodules from malignant ones. It is suggested that further prospective clinical trials be conducted to evaluate the accuracy of such findings in a larger cohort and determine the clinical uses.

Real-World Data for Lenvatinib in Radioiodine-Refractory Differentiated Thyroid Cancer (RELEVANT): A Retrospective Multicentric Analysis of Clinical Practice in Austria

BACKGROUND

Lenvatinib has proven efficacy in progressive, radioiodine- (RAI-) refractory thyroid cancer (TC). Dose reductions are commonly performed due to decreased tolerability and adverse effects. This retrospective multicenter study analyzed overall survival (OS) and progression-free survival (PFS) and tolerability in the Austrian patient population treated with lenvatinib.

METHODS

Clinical data of 43 patients (25 males and 18 females) with a median age of 70 years (range: 39-91 years) and RAI-refractory TC with metastases to the lymph nodes (74%), lungs (86%), bone (35%), liver (16%), and brain (12%) were analyzed. The mean duration of treatment with lenvatinib was 26.6 ± 15.4 months with dosage reductions required in 39 patients (91%).

RESULTS

PFS after 24 months was 71% (95% CI: 56-87), and overall survival (OS) was 74% (95% CI: 60-88), respectively. OS was significantly shorter (p=0.048) in patients with a daily maintenance dosage ≤ 10 mg (63%) (95% CI: 39-86) as compared to patients on ≥ 14 mg lenvatinib (82%) (95% CI: 66-98) daily. Dose reduction was noted in 39 patients (91%). Grade ≥3 toxicities (hypertension, diarrhea, weight loss, and palmar-plantar erythrodysesthesia syndrome) were most common leading to discontinuation of lenvatinib in 7 patients (16%).

CONCLUSION

Lenvatinib showed sustained clinical efficacy in patients with metastatic RAI-refractory TC even with reduced maintenance dosages over years. The effects were comparable to the registration trial, although patients had a higher median age and, more commonly, dose reductions.

Association between Circulating Fibroblast Growth Factor 21 and Aggressiveness in Thyroid Cancer

Fibroblast growth factor 21 (FGF21) plays important roles in regulating glucose, lipid, and energy metabolism; however, its effects in tumors remain poorly understood. To understand the role of FGF21 in regulating tumor aggressiveness in thyroid cancer, serum levels of FGF21 were measured in healthy subjects and patients with papillary thyroid cancer (PTC), and expression levels of FGF21, FGF receptors (FGFRs), and β-klotho (KLB) were investigated in human thyroid tissues. The cell viability, migrating cells, and invading cells were measured in PTC cells after treatment with recombinant FGF21. Higher serum levels of FGF21 were found in patients with thyroid cancer than in control participants, and were significantly associated with body mass index (BMI), fasting glucose levels, triglyceride levels, tumor stage, lymphovascular invasion, and recurrence. Serum FGF21 levels were positively correlated with the BMI in patients with PTC, and significantly associated with recurrence. Recombinant FGF21 led to tumor aggressiveness via activation of the FGFR signaling axis and epithelial-to-mesenchymal transition (EMT) signaling in PTC cells, and AZD4547, an FGFR tyrosine kinase inhibitor, attenuated the effects of FGF21. Hence, FGF21 may be a new biomarker for predicting tumor progression, and targeting FGFR may be a novel therapy for the treatment of obese patients with PTC.

Genetic polymorphisms of miRNA let7a-2 and pri-mir-34b/c are associated with an increased risk of papillary thyroid carcinoma and clinical/pathological features

microRNAs (miRNAs) as a group of short noncoding RNAs are crucial molecules in transcriptional and translational regulation of oncogenes and tumor suppressor genes. Evidence showed there was an association between the miRNA polymorphisms and various cancers, including papillary thyroid carcinoma (PTC). The present study aims to evaluate the possible effects of let7a-2 rs1143770 and pri-mir-34b/c rs4938723 polymorphisms on PTC susceptibility. A total of 120 patients with PTC and 130 age, sex, and race matched controls were enrolled in the case-control study. The polymerase chain reaction-restriction fragment length polymorphism method was used for genotyping of let7a-2 rs1143770 and pri-mir-34b/c rs4938723 polymorphisms. The let7a-2 rs1143770 CT and TT genotypes were associated with a 1.9-fold and 2.2-fold higher risk of PTC, respectively (P = 0.027 and P = 0.041). Moreover, the let7a-2 rs1143770 polymorphism was associated with increased PTC risk in both dominant (2-fold, P = 0.015) and the allelic model (1.5-fold, P = 0.03). The frequency of pri-mir-34b/c rs4938723TC genotype was significantly higher in patients with PTC and associated with a two-fold higher risk of PTC (P = 0.013). In addition, this polymorphism was associated with a 1.8-fold increased risk of PTC in dominant model (P = 0.021). The let7a-2 rs1143770CT genotype was associated with a 3.5-fold increased risk of N1 stage in PTC patients (P = 0.04), however, pri-mir-34b/c rs4938723TC genotype was associated with a 3.4-fold and 5.1-fold increased risk of III-IV stage and vascular invasion in PTC group, respectively (P = 0.04 and P = 0.04). In conclusion, the present study shows that let7a-2 rs1143770 and pri-mir-34b/c rs4938723 polymorphisms could be susceptible factors for PTC and some clinical features.

Impact of dose interruption on the efficacy of lenvatinib in a phase 3 study in patients with radioiodine-refractory differentiated thyroid cancer

BACKGROUND

In the phase 3 Study of (E7080) Lenvatinib in Differentiated Cancer of the Thyroid (SELECT), lenvatinib significantly improved efficacy outcomes versus placebo in patients with radioiodine-refractory differentiated thyroid cancer (RR-DTC). Lenvatinib-treated patients had more adverse events (AEs), which were generally managed with dose modifications, including dose interruption. This exploratory post hoc analysis investigated the impact of dose interruption on lenvatinib efficacy.

METHODS

Dose modifications were required for grade 3 or intolerable grade 2 AEs in SELECT. Lenvatinib-treated patients were dichotomised based on the duration of dose interruption relative to total treatment duration: shorter dose interruption (<10% of total treatment duration) and longer dose interruption (≥10%).

RESULTS

At the time of primary data cut-off (November 15, 2013; median follow-up, 17.1 months), the median progression-free survival (PFS) for the shorter dose-interruption group had not yet been reached, whereas median PFS for the longer dose-interruption group was 12.8 months (95% confidence interval [CI], 9.3-16.5). Compared with placebo, the hazard ratios for PFS in the shorter and longer dose-interruption groups were 0.14 (95% CI, 0.09-0.20) and 0.31 (95% CI, 0.22-0.43), respectively. In a multivariate model, dose interruption was significantly associated with lenvatinib efficacy, even after adjustment for patient characteristics.

CONCLUSIONS

Lenvatinib improved efficacy outcomes versus placebo in patients with RR-DTC, regardless of the duration of dose interruption; however, those with shorter dose interruptions had a greater magnitude of benefit versus those with longer interruptions. This analysis highlights the importance of timely management of lenvatinib toxicities to minimise dose interruptions and maximise lenvatinib efficacy in patients with RR-DTC. CLINICALTRIALS.

GOV NUMBER

NCT01321554.

Curcumin induces endoplasmic reticulum stress-associated apoptosis in human papillary thyroid carcinoma BCPAP cells via disruption of intracellular calcium homeostasis

BACKGROUND

Thyroid cancer is the most common endocrine tumor. Our previous studies have demonstrated that curcumin can induce apoptosis in human papillary thyroid carcinoma BCPAP cells. However, the underlined mechanism has not been clearly elucidated. Endoplasmic reticulum (ER) is a major organelle for synthesis, maturation, and folding proteins as well as a large store for Ca. Overcoming chronically activated ER stress by triggering pro-apoptotic pathways of the unfolded protein response (UPR) is a novel strategy for cancer therapeutics. Our study aimed to uncover the ER stress pathway involved in the apoptosis caused by curcumin.

METHODS

BCPAP cells were treated with different doses of curcumin (12.5-50 μM). Annexin V/PI double staining was used to determine cell apoptosis. Rhod-2/AM calcium fluorescence probe assay was performed to measure the calcium level of endoplasmic reticulum. Western blot was used to examine the expression of ER stress marker C/EBP homologous protein 10 (CHOP) and glucose-regulated protein 78 (GRP78). X-box binding protein1 (XBP-1) spliced form was examined by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Curcumin significantly inhibited anchorage-independent cell growth and induced apoptosis in BCPAP cells. Curcumin induced ER stress and UPR responses in a dose- and time-dependent manner, and the chemical chaperone 4-phenylbutyrate (4-PBA) partially reversed the antigrowth activity of curcumin. Moreover, curcumin significantly increased inositol-requiring enzyme 1α (IRE1α) phosphorylation and XBP-1 mRNA splicing to induce a subsets of ER chaperones. Increased cleavage of activating transcription factor 6 (ATF6), which enhances expression of its downstream target CHOP was also observed. Furthermore, curcumin induced intracellular Ca influx through inhibition of the sarco-endoplasmic reticulum ATPase 2A (SERCA2) pump. The increased cytosolic Ca then bound to calmodulin to activate calcium/calmodulin-dependent protein kinase II (CaMKII) signaling, leading to mitochondrial apoptosis pathway activation. Ca chelator BAPTA partially reversed curcumin-induced ER stress and growth suppression, confirming the possible involvement of calcium homeostasis disruption in this response.

CONCLUSIONS

Curcumin inhibits thyroid cancer cell growth, at least partially, through ER stress-associated apoptosis. Our observations provoked that ER stress activation may be a promising therapeutic target for thyroid cancer treatment.(Figure is included in full-text article.).

Downregulation of SKP2 in Papillary Thyroid Cancer Acts Synergistically With TRAIL on Inducing Apoptosis via ROS

CONTEXT AND OBJECTIVE

S-phase kinase protein 2 (SKP2) is an F-box protein with proteasomal properties and has been found to be overexpressed in a variety of cancers. However, its role in papillary thyroid cancer (PTC) has not been fully elucidated.

EXPERIMENTAL DESIGN

SKP2 expression was assessed by immunohistochemistry in a tissue microarray format on a cohort of >1000 PTC samples. In vitro and in vivo studies were performed using proteasome inhibitor bortezomib and proapoptopic death ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) either alone or in combination on PTC cell lines.

RESULTS

SKP2 was overexpressed in 45.5% of PTC cases and was significantly associated with extrathyroidal extension (P = 0.0451), distant metastasis (P = 0.0435), and tall cell variant (P = 0.0271). SKP2 overexpression was also directly associated with X-linked inhibitor of apoptosis protein overexpression (P < 0.0001) and Bcl-xL overexpression (P = 0.0005) and inversely associated with death receptor 5 (P < 0.0001). The cotreatment of bortezomib and TRAIL synergistically induced apoptosis via mitochondrial apoptotic pathway in PTC cell lines. Furthermore, bortezomib and TRAIL synergistically induced reactive oxygen species (ROS) generation and caused death receptor 5 upregulation through activation of the extracellular signal-regulated kinase-C/EBP homologous protein signaling cascade. Finally, bortezomib treatment augmented the TRAIL-mediated anticancer effect on PTC xenograft tumor growth in nude mice.

CONCLUSION

These data suggest that SKP2 is a potential therapeutic target in PTC and that a combination of bortezomib and TRAIL might be a viable therapeutic option for the treatment of patients with aggressive PTC.

Lenvatinib for Anaplastic Thyroid Cancer

BACKGROUND

Lenvatinib has been approved by regulatory agencies in Japan, the United States, and the European Union for treatment of radioiodine-refractory differentiated thyroid cancer (RR-DTC). Thyroid cancer, however, is a clinically diverse disease that includes anaplastic thyroid cancer (ATC), the subtype associated with the highest lethality. Effective therapy for ATC is an unmet need.

PATIENTS AND METHODS

This phase 2, single-arm, open-label study in patients with thyroid cancer, including ATC, RR-DTC, and medullary thyroid cancer was conducted from 3 September 2012 to 9 July 2015. Patients received lenvatinib 24 mg daily until disease progression or development of unacceptable toxicity. The primary endpoint was safety, and the secondary endpoint was efficacy, as assessed by progression-free survival (PFS), overall survival (OS), and objective response rate.

RESULTS

At data cutoff, 17 patients with ATC were enrolled. All experienced ≥1 treatment-emergent adverse event (TEAE). The most frequent TEAEs were decreased appetite (82%), hypertension (82%), fatigue (59%), nausea (59%), and proteinuria (59%). Of note, only one patient required lenvatinib withdrawal because of a TEAE, and this TEAE was considered unrelated to lenvatinib. The median PFS was 7.4 months [95% confidence interval (CI): 1.7-12.9], the median OS was 10.6 months (95% CI: 3.8-19.8), and the objective response rate was 24%.

CONCLUSION

In this study, lenvatinib demonstrated manageable toxicities with dose adjustments and clinical activity in patients with ATC. This clinical activity of lenvatinib warrants further investigation in ATC.

CLINICALTRIALSGOV

NCT01728623.

Neoadjuvant Therapy in Differentiated Thyroid Cancer

Objectives. Invasion of differentiated thyroid cancer (DTC) into surrounding structures can lead to morbid procedures such as laryngectomy and tracheal resection. In these patients, there is a potential role for neoadjuvant therapy. Methods. We identified three studies involving the treatment of DTC with neoadjuvant chemotherapy: two from Slovenia and one from Japan. Results. These studies demonstrate that in selected situations, neoadjuvant chemotherapy can have a good response and allow for a more complete surgical resection, the treatment of DTC. Additionally, the SELECT trial shows that the targeted therapy lenvatinib is effective in the treatment of DTC and could be useful as neoadjuvant therapy for this disease due to its short time to response. Pazopanib has also demonstrated promise in phase II data. Conclusions. Thus, chemotherapy in the neoadjuvant setting could possibly be useful for managing advanced DTC. Additionally, some of the new tyrosine kinase inhibitors (TKIs) hold promise for use in the neoadjuvant setting in DTC.

Polymorphisms within base and nucleotide excision repair pathways and risk of differentiated thyroid carcinoma

The thyrocytes are exposed to high levels of oxidative stress which could induce DNA damages. Base excision repair (BER) is one of the principal mechanisms of defense against oxidative DNA damage, however recent evidences suggest that also nucleotide excision repair (NER) could be involved. The aim of present work was to identify novel differentiated thyroid cancer (DTC) risk variants in BER and NER genes. For this purpose, the most strongly associated SNPs within NER and BER genes found in our previous GWAS on DTC were selected and replicated in an independent series of samples for a new case-control study. Although a positive signal was detected at the nominal level of 0.05 for rs7689099 (encoding for an aminoacid change proline to arginine at codon 117 within NEIL3), none of the considered SNPs (i.e. rs7990340 and rs690860 within RFC3, rs3744767 and rs1131636 within RPA1, rs16962916 and rs3136166 in ERCC4, and rs17739370 and rs7689099 in NEIL3) was associated with the risk of DTC when the correction of multiple testing was applied. In conclusion, a role of NER and BER pathways was evoked in the susceptibility to DTC. However, this seemed to be limited to few polymorphic genes and the overall effect size appeared weak.

Spanish consensus for the management of patients with advanced radioactive iodine refractory differentiated thyroid cancer

BACKGROUND

Approximately one third of the patients with differentiated thyroid cancer (DTC) who develop structurally-evident metastatic disease are refractory to radioactive iodine (RAI). Most deaths from thyroid cancer occur in these patients. The main objective of this consensus is to address the most controversial aspects of management of these patients.

METHODS

On behalf of the Spanish Society of Endocrinology & Nutrition (SEEN) and the Spanish Group for Orphan and Infrequent Tumors (GETHI), the Spanish Task Force for Thyroid Cancer, consisting of endocrinologists and oncologists, reviewed the relevant literature and prepared a series of clinically relevant questions related to management of advanced RAI-refractory DTC.

RESULTS

Ten clinically relevant questions were identified by the task force. In answering to these 10 questions, the task force included recommendations regarding the best definition of refractoriness; the best therapeutic options including watchful waiting, local therapies, and systemic therapy (e.g. kinase inhibitors), when sodium iodide symporter (NIS) restoration may be expected; and how recent advances in molecular biology have increased our understanding of the disease.

CONCLUSIONS

In response to our appointment as a task force by the SEEN and GHETI, we developed a consensus to help in clinical management of patients with advanced RAI-refractory DTC. We think that this consensus will provide helpful and current recommendations that will help patients with this disorder to get optimal medical care.

[Consensus statement for accreditation of multidisciplinary thyroid cancer units]

Thyroid cancer is the leading endocrine system tumor. Great advances have recently been made in understanding of the origin of these tumors and the molecular biology that makes them grow and proliferate, which have been associated to improvements in diagnostic procedures and increased availability of effective local and systemic treatments. All of the above makes thyroid cancer a paradigm of how different specialties should work together to achieve the greatest benefit for the patients. Coordination of all the procedures and patient flows should continue throughout diagnosis, treatment, and follow-up, and is essential for further optimization of resources and time. This manuscript was prepared at the request of the Working Group on Thyroid Cancer of the Spanish Society of Endocrinology and Nutrition, and is aimed to provide a consensus document on the definition, composition, requirements, structure, and operation of a multidisciplinary team for the comprehensive care of patients with thyroid cancer. For this purpose, we have included contributions by several professionals from different specialties with experience in thyroid cancer treatment at centers where multidisciplinary teams have been working for years, with the aim of developing a practical consensus applicable in clinical practice.

Expression of YY1 in Differentiated Thyroid Cancer

The transcription factor Yin Yang 1 (YY1) has an important regulatory role in tumorigenesis, but its implication in thyroid cancer has not been yet investigated. In the present study, we have analyzed the expression of YY1 in differentiated thyroid cancer and assessed the association of YY1 expression with clinical features. Expression of YY1 was evaluated in human thyroid cancer cell lines, a series of matched normal/tumor thyroid tissues and in a thyroid cancer tissue microarray, using real-time PCR, Western blot, and/or immunohistochemistry. YY1 was overexpressed in thyroid cancer cells, at transcription and protein levels. A significant increase of YY1 mRNA was also observed in tumor thyroid tissues. Moreover, immunohistochemical analysis of the thyroid cancer tissue microarray revealed that both papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC) present increased YY1 protein levels (48 and 19%, respectively). After stratification by the level of YY1 protein, positive YY1 expression identifies 88% of patients with PTC. The association of YY1 expression with clinicopathological features in PTC and FTC showed that YY1 expression was related with age at diagnosis. Our data indicates for the first time overexpression of YY1 in differentiated thyroid cancer, with YY1 being more frequently overexpressed in the PTC subtype.

The Clinicopathological Features of BRAF Mutated Papillary Thyroid Cancers in Chinese Patients

The BRAF(V600E) mutation is commonly found in papillary thyroid cancers (PTCs) at different frequencies in different regions. However, the association between the BRAF(V600E) mutation and clinicopathological features in Chinese PTC patients is unknown. A total of 543 Chinese patients with histologically confirmed PTC were enrolled in this study. For the BRAF mutation assay, the target fragments were amplified and sequenced with an ABI 3500 gene analyzer. In 170 of 543 samples (31.3%), the BRAF(V600E) mutation was detected. In the bivariate analysis, the BRAF(V600E) mutation showed an association with bilaterality, tumor size, extrathyroidal invasion, and lymph node metastases (LNM). However, in the multivariate analysis, the BRAF(V600E) mutation was positively related to only tumor size (>1 cm) and extrathyroidal invasion. In addition, the multivariate analysis also showed that the age at diagnosis (<45 y) and tumor size (>1 cm) were independent predictors for LNM. In this study, the BRAF(V600E) mutation is positively associated with worse prognostic factors, including larger tumor size and the tumor extending to the thyroid capsule or extrathyroidal region; however, it is not an independent predictor for LNM.

Molecular profiling of thyroid cancer subtypes using large-scale text mining

Background

Thyroid cancer is the most common endocrine tumor with a steady increase in incidence. It is classified into multiple histopathological subtypes with potentially distinct molecular mechanisms. Identifying the most relevant genes and biological pathways reported in the thyroid cancer literature is vital for understanding of the disease and developing targeted therapeutics.

Results

We developed a large-scale text mining system to generate a molecular profiling of thyroid cancer subtypes. The system first uses a subtype classification method for the thyroid cancer literature, which employs a scoring scheme to assign different subtypes to articles. We evaluated the classification method on a gold standard derived from the PubMed Supplementary Concept annotations, achieving a micro-average F1-score of 85.9% for primary subtypes. We then used the subtype classification results to extract genes and pathways associated with different thyroid cancer subtypes and successfully unveiled important genes and pathways, including some instances that are missing from current manually annotated databases or most recent review articles.

Conclusions

Identification of key genes and pathways plays a central role in understanding the molecular biology of thyroid cancer. An integration of subtype context can allow prioritized screening for diagnostic biomarkers and novel molecular targeted therapeutics. Source code used for this study is made freely available online at https://github.com/chengkun-wu/GenesThyCan.

Poorly differentiated thyroid cancer

PURPOSE OF REVIEW

Poorly differentiated thyroid carcinomas (PDTCs) comprise a small subset of heterogeneous thyroid tumors, occupying an intermediate area between well differentiated follicular or papillary carcinoma and anaplastic carcinomas, from both a histopathogenetic and a clinical point of view. PDTCs are more aggressive than the well differentiated, but less aggressive than the anaplastic thyroid cancers. They have a distinct biological behavior, and the classification of these tumors into a separate group appears justified.

RECENT FINDINGS

The criteria used to diagnose PDTC have been an area of controversy. The multiple definitions of PDTC make the literature difficult to interpret. No clinical features can accurately diagnose PDTCs. Thus, the results of histocytology, immunohistochemistry, and molecular genetics tests aid in diagnosis. Given the aggressiveness of PDTCs, with increased recurrence and decreased survival rates, a multimodality treatment approach is required.

SUMMARY

We conducted a comprehensive review of the current diagnostic and therapeutic tools in the management of patients with PDTCs. The present article aims to review the various aspects of this tumor type, from morphology to immunohistochemistry, and molecular abnormalities from a practical and daily practice-oriented point of view.

Novel genome-wide association study-based candidate loci for differentiated thyroid cancer risk

CONTEXT

Genome-wide association studies (GWASs) on differentiated thyroid cancer (DTC) have identified robust associations with single nucleotide polymorphisms (SNPs) at 9q22.33 (FOXE1), 14q13.3 (NKX2-1), and 2q35 (DIRC3). Our recently published GWAS suggested additional susceptibility loci specific for the high-incidence Italian population.

OBJECTIVE

The purpose of this study was to identify novel Italian-specific DTC risk variants based on our GWAS and to test them further in low-incidence populations.

DESIGN

We investigated 45 SNPs selected from our GWAS first in an Italian population. SNPs that showed suggestive evidence of association were investigated in the Polish and Spanish cohorts.

RESULTS

The combined analysis of the GWAS and the Italian replication study (2260 case patients and 2218 control subjects) provided strong evidence of association with rs10136427 near BATF (odds ratio [OR] =1.40, P = 4.35 × 10(-7)) and rs7267944 near DHX35 (OR = 1.39, P = 2.13 × 10(-8)). A possible role in DTC susceptibility in the Italian populations was also found for rs13184587 (ARSB) (P = 8.54 × 10(-6)) and rs1220597 (SPATA13) (P = 3.25 × 10(-6)). Only the associations between rs10136427 and rs7267944 and DTC risk were replicated in the Polish and the Spanish populations with little evidence of population heterogeneity (GWAS and all replications combined, OR = 1.30, P = 9.30 × 10(-7) and OR = 1.32, P = 1.34 × 10(-8), respectively). In silico analyses provided new insights into the possible functional consequences of the SNPs that showed the strongest association with DTC.

CONCLUSIONS

Our findings provide evidence for novel DTC susceptibility variants. Further studies are warranted to identify the specific genetic variants responsible for the observed associations and to functionally validate our in silico predictions.

Thyroid cancer: SEOM clinical guidelines

Thyroid cancer (TC) is the most common type of endocrine malignancy and accounts for nearly 3 % of all malignancies. The incidence of TC in Spain was 5/100,000 in women and 1.9/100,000 in men in 2013. The diagnosis of TC usually follows the identification of a thyroid nodule on physical examination or as an incidental finding on diagnostic imaging performed for other reasons. In most of the cases, the prognosis is excellent but despite low mortality rates, local recurrence occurs in up to 20 %, and distant metastases can occur in approximately 10 % at 10 years. The better knowledge of molecular biology of TC has allowed to the development of new targeted agents directed to the main pathways involved in TC pathogenesis. Knowing all these new strategies will help us face the therapeutic management of TC more effectively.

Multikinase inhibitors in the treatment of thyroid cancer: specific role of lenvatinib

Thyroid cancers are the most frequent neoplasms of the endocrine system and in the initial stages their prognosis is excellent. However, few therapeutic options are available for advanced or metastatic disease. In the last decade, a better understanding of the molecular events involved in the tumorigenesis of thyroid cancers has led to development of new targeted agents for the management of advanced and refractory disease. Multikinase inhibitors that are able to block pathways involved in the proliferation, invasion, and neoangiogenesis of thyroid cancer have been the most widely studied. After an international effort to identify and recruit sufficient patients, four placebo-controlled studies of multikinase inhibitors have been completed. These trials have led to the approval of the first agents with activity in advanced medullary thyroid cancers, which will probably change the landscape of treatment for iodine-refractory differentiated thyroid cancer in the near future. The purpose of this paper is to review the development of targeted agents for thyroid malignancy, with a special focus on lenvatinib, a multikinase inhibitor.

High prevalence of mTOR complex activity can be targeted using Torin2 in papillary thyroid carcinoma

The mammalian target of rapamycin (mTOR) signaling cascade is a key regulatory pathway controlling initiation of messenger RNA in mammalian cells. Although dysregulation of mTOR signaling has been reported earlier in cancers, there is paucity of data about mTOR expression in papillary thyroid carcinoma (PTC). Therefore, in this study, we investigated the presence of mTORC2 and mTORC1 complexes in a large cohort of >500 PTC samples. Our clinical data showed the presence of active mTORC1 and mTORC2 in 81 and 39% of PTC samples, respectively. Interestingly, coexpression of mTORC1 and mTORC2 activity was seen in a 32.5% (164/504) of the PTC studied and this association was statistically significant (P = 0.0244). mTOR signaling complex was also found to be associated with activated AKT and 4E-BP1. In vitro, using Torin2, a second-generation mTOR inhibitor or gene silencing of mTOR expression prevented mTORC1 and mTORC2 activity leading to inactivation of P70S6, 4E-BP1, AKT and Bad. Inhibition of mTOR activity led to downregulation of cyclin D1, a gene regulated by messenger RNA translation via phosphorylation of 4E-BP1. Torin2 treatment also inhibited cell viability and induced caspase-dependent apoptosis via activation of mitochondrial apoptotic pathway in PTC cells. Finally, Torin2 treatment induces anticancer effect on PTC xenograft tumor growth in nude mice via inhibition of mTORC1 and mTORC2 and its associated pathways. Our results suggest that coexpression of mTORC1 and mTORC2 is seen frequently in the clinical PTC samples and dual targeting of mTORC1 and mTORC2 activity may be an attractive therapeutic target for treatment of PTC.

Comprehensive literature review: recent advances in diagnosing and managing patients with poorly differentiated thyroid carcinoma

Poorly differentiated thyroid carcinomas are a rare form of thyroid carcinomas; they display an intermediate behavior between well-differentiated and anaplastic thyroid carcinomas. PDTCs are more aggressive than the well-differentiated, but less aggressive than the undifferentiated or anaplastic, forms. No clinical features can accurately diagnose poorly differentiated thyroid carcinomas. Thus, the results of histocytology, immunohistochemistry, and molecular genetics tests aid in diagnosis. Given the aggressiveness of poorly differentiated thyroid carcinomas and the poor survival rates in patients who undergo surgery alone, a multimodality treatment approach is required. We conducted a comprehensive review of the current diagnostic and therapeutic tools in the management of patients with poorly differentiated thyroid carcinomas.

New molecular targeted therapy and redifferentiation therapy for radioiodine-refractory advanced papillary thyroid carcinoma: literature review

Although the majority of papillary thyroid carcinoma could be successfully managed by complete surgical resection alone or resection followed by radioiodine ablation, a small proportion of patients may develop radioiodine-refractory progressive disease which is not amenable to surgery, local ablative treatment or other treatment modalities. The use of FDG-PET/CT scan for persistent/recurrent disease has improved the accuracy of restaging as well as cancer prognostication. Given that patients with RAI-refractory disease tend to do significantly worse than those with radioiodine-avid or non-progressive disease, an increasing number of phase I and II studies have been conducted to evaluate the efficacy of new molecular targeted drugs such as the tyrosine kinase inhibitors and redifferentiation drugs. The overall response rate of these drugs ranged between 0–53%, depending on whether the patients had been previously treated with these drugs, performance status and extent of disease. However, drug toxicity remains a major concern in administration of target therapies. Nevertheless, there are also ongoing phase III studies evaluating the efficacy of these new drugs. The aim of the review was to summarize and discuss the results of these targeted drugs and redifferentiation agents for patients with progressive, radioiodine-refractory papillary thyroid carcinoma.