Intensity of vascular endothelial growth factor expression is associated with increased risk of recurrence and decreased disease-free survival in papillary thyroid cancer

The role of vascular endothelial growth factor in the development of papillary thyroid carcinoma in patients with lymphocytic thyroiditis

BACKGROUND

Vascular endothelial growth factor (VEGF) plays a pivotal role in the pathogenesis of autoimmune chronic inflammatory conditions and papillary thyroid carcinoma (PTC). We hypothesized that, as VEGF expression is increased both in PTC and in lymphocytic thyroiditis (LT), it may stimulate the development of PTC in patients with LT. To evaluate this, we examined both tumor and adjacent non-tumoral tissues of PTC patients with and without LT.

METHODS

A total of 50 patients with PTC (52.50±7.41 years) and 17 patients with nodular goiter (NG) (50.47±10.38 years) were included in the study. According to the presence of LT, patients with PTC were further divided into two groups. Immunohistochemical analyses of VEGF were conducted in all patients and for PTC patients, both tumor tissue and adjacent non-tumoral tissue were evaluated.

RESULTS

The scores for intensity of staining and percentage of labeled thyrocytes for VEGF were found to be significantly higher in the PTC patients than in the NG patients (P<0.001, P<0.001, respectively). The tumor tissue revealed similar scores for PTC patients with LT and without LT. However, the scores in adjacent non-tumoral tissue were higher in PTC patients with LT than in patients without LT (P=0.004, P=0.01, respectively).

CONCLUSIONS

To the best of our knowledge, our results are the first to demonstrate that the expression of VEGF in adjacent non-tumoral tissue were higher in PTC patients with LT than in those without, which shows a possible role of VEGF expression in the progression of PTC in the presence of LT.

Role of PET/Computed Tomography in Elderly Thyroid Cancer: Tumor Biology and Clinical Management

PET/computed tomography (CT) studies can be potentially useful in elderly thyroid carcinoma patients for exploring the disease biology, especially in metastatic setting and thereby directing appropriate therapeutic management on case-to-case basis, adopting nuclear theranostics, and disease prognostication. With the availability of multiple PET radiopharmaceuticals, it would be worthwhile to evolve and optimally use FDG and the other non-fluorodeoxyglucose and investigational PET/CT tracers as per the clinical situation and need and thereby define their utilities in a given case scenario. In this regard, (I) differentiated thyroid carcinoma (DTC) including radioiodine refractory disease, poorly differentiated thyroid cancer (PDTC) and TENIS, (II) medullary thyroid carcinoma (MTC), (III) anaplastic carcinoma and (IV) Primary thyroid lymphoma (PTL) should be viewed and dealt separately.

Advances in pharmacotherapy for advanced thyroid cancer of follicular origin (PTC, FTC). New approved drugs and future therapies

INTRODUCTION

The most common altered signaling found in aggressive iodine-refractory Thyroid cancer derived from follicular cells (RAI-TC) are RTK, MAPK, PI3K, WNT, BRAF, RAS, RET, and TP53. Tyrosine Kinase Inhibitors (TKI) are multi-kinase inhibitors able to act against different pathways, that elicit an anti-neoplastic activity.

AREAS COVERED

The aim of this paper is to review recent novel molecular therapies of RAI-TC. Recently, sorafenib and lenvatinib, have been approved for the treatment of aggressive RAI-TC. Other studies are evaluating vandetanib and selumetinib in RAI-TC. Furthermore, preliminary studies have evaluated dabrafenib, and vemurafenib in BRAF mutated RAI-TC patients to re-induce 131-iodine uptake. The interplay between cells of the immune system and cancer cells can be altered by immune checkpoints inhibitors. The expression of PDL1 in RAI-TC was related to tumor recurrence and poor survival. Several clinical trials are investigating a combination of different therapies, such as lenvatinib and pembrolizumab.

EXPERT OPINION

Mechanisms of resistance to TKIs inhibitors can be of intrinsic or acquired origin. An acquired resistance to lenvatinib, or sorafenib can be due to upregulation of FGFR; therefore anti-FGFR agents are evaluated. A new strategy is to combine TKIs with immunotherapy. Several studies are evaluating lenvatinib and pembrolizumab in RAI-TC patients.

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.

Molecular targets of tyrosine kinase inhibitors in thyroid cancer

Thyroid cancer (TC) is the eighth most frequently diagnosed cancer worldwide with a rising incidence in the past 20 years. Surgery is the primary strategy of therapy for patients with medullary TC (MTC) and differentiated TC (DTC). In DTC patients, radioactive iodine (RAI) is administered after thyroidectomy. Neck ultrasound, basal and thyroid-stimulating hormone-stimulated thyroglobulin are generally performed every three to six months for the first year, with subsequent intervals depending on initial risk assessment, for the detection of possible persistent/recurrent disease during the follow up. Distant metastases are present at the diagnosis in ∼5 % of DTC patients; up to 15 % of patients have recurrences during the follow up, with a survival reduction (70 %-50 %) at 10-year. During tumor progression, the iodide uptake capability of DTC cancer cells can be lost, making them refractory to RAI, with a negative impact on the prognosis. Significant advances have been done recently in our understanding of the molecular pathways implicated in the progression of TCs. Several drugs have been developed, which inhibit signaling kinases or oncogenic kinases (BRAF^V600E, RET/PTC), such as those associated with Platelet-Derived Growth Factor Receptor and Vascular Endothelial Growth Factor Receptor. Tyrosine kinase receptors are involved in cancer cell proliferation, angiogenesis, and lymphangiogenesis. Several tyrosine kinase inhibitors (TKIs) are emerging as new treatments for DTC, MTC and anaplastic TC (ATC), and can induce a clinical response and stabilize the disease. Lenvatinib and sorafenib reached the approval for RAI-refractory DTC, whereas cabozantinib and vandetanib for MTC. These TKIs extend median progression-free survival, but do not increase the overall survival. Severe side effects and drug resistance can develop in TC patients treated with TKIs. Additional studies are needed to identify a potential effective targeted therapy for aggressive TCs, according to their molecular characterization.

Primary cell cultures for the personalized therapy in aggressive thyroid cancer of follicular origin

Thyroid cancer (TC) is the most prevalent endocrine malignancy. More than 90 % of TC is represented by differentiated TC (DTC) arising from the follicular thyroid cells. DTC includes papillary TC (PTC), follicular TC (FTC), and Hürthle cell TC. Anaplastic TC (ATC) accounts for 1% of TC, and it represents 15-40 % of TC death. Current treatment strategies are not completely effective against aggressive DTC or ATC, and mortality is one of the most important challenges. Recently, progresses have been obtained in the understanding of the molecular/genetic basis of TC progression, and new drugs have been introduced [i.e. tyrosine kinase inhibitors (TKIs)], able to block the oncogenic or signaling kinases, associated with cellular growth. Thyroid cell lines, obtained from tumoral cells and chosen for high proliferation in vitro, have been used as preclinical models. Actually, these cells lose the characteristic features of the primary tumor, because they adapt to in vitro growth conditions. For these reasons, the use of these cell lines has important limitations, and more recently human primary cell cultures have been established as monolayer cultures, and investigated for their biological behavior. Moreover, in the past, primary TC cells could be collected only through surgical biopsies, while recently human primary cell cultures can be established also from samples of fine-needle aspiration citology from aggressive dedifferentiated DTC or ATC. Testing in vitro different TKIs in each patient can help to develop new personalized treatments, without using ineffective drugs. In conclusion, personalized medicine and precise oncology, which consider both patients and their disease features, represent the future of the treatment approach, and further progress is needed in this direction.

Bone metastases in thyroid cancer

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Osseous metastases (OMs) occur in only 4% of all thyroid cancer patients but are associated with greatly increased morbidity and mortality.

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OMs are about twice as frequent in follicular, hurthle cell, and medullary thyroid cancers as compared to papillary thyroid cancers.

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OMs are often lytic, triggered via activation of osteoclasts by tumor cells in a “vicious cycle”.

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OMs are often initially asymptomatic, but associated with eventual skeletal related events in >75%.

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Early identification of OMs, preemptive treatment with antiresorptive agents, and aggressive treatment of focal lesions before crisis are key.

Whereas preemptive screening for the presence of lymph node and lung metastases is standard-of-care in thyroid cancer patients, bone metastases are less well studied and are often neglected in thyroid cancer patient surveillance. Bone metastases in thyroid cancer are, however, independently associated with poor/worse prognosis with a median overall survival from detection of only 4 years despite an otherwise excellent prognosis for the vast majority of thyroid cancer patients. In this review we summarize the state of current knowledge as pertinent to bony metastatic disease in thyroid cancer, including clinical implications, impacts on patient function and quality of life, pathogenesis, and therapeutic opportunities, proposing approaches to patient care accordingly. In particular, bone metastasis pathogenesis appears to reflect cooperatively between cancer and the bone microenvironment creating a “vicious cycle” of bone destruction rather than due exclusively to tumor invasion into bone. Additionally, bone metastases are more frequent in follicular and medullary thyroid cancers, requiring closer bone surveillance in patients with these histologies. Emerging data also suggest that treatments such as multikinase inhibitors (MKIs) can be less effective in controlling bone, as opposed to other (e.g. lung), metastases in thyroid cancers, making special attention to bone critical even in the setting of active MKI therapy. Although locoregional therapies including surgery, radiotherapy and ablation play important roles in palliation, antiresorptive agents including bisphosphonates and denosumab appear individually to delay and/or lessen skeletal morbidity and complications, with dosing frequency of every 3 months appearing optimal; their early application should therefore be strongly considered.

Novel treatments for anaplastic thyroid carcinoma

Anaplastic thyroid cancer (ATC) is one of the deadliest human cancers and it is less than 2% of thyroid carcinomas (TCs). The standard treatment of ATC includes surgical debulking, accelerated hyperfractionated external beam radiation therapy (EBRT), and chemotherapy, in particular with cisplatin or doxorubicin, achieving about 10 months of median survival. Since ATC is a rare and aggressive tumor, it is still challenging to predict the patient clinical therapy responsiveness. Several genetic mutations have been described in ATC, involved in different molecular pathways linked to tumor progression, and novel therapies acting on these molecular pathways have been investigated, to improve the quality of life in these patients. Here we review the new targeted therapy of ATC. We report interesting results obtained with molecules targeting different pathways: angiogenesis (vandetanib, combretastatin, sorafenib, lenvatinib, sunitinib, CLM94, CLM3, etc.); EGFR (gefitinib, docetaxel); BRAF (dabrafenib/trametinib, vemurafenib); PPARγ agonists (rosiglitazone, pioglitazone, efatutazone); PD-1 and PD-L1 (pembrolizumab); TERT. To escape resistance to monotherapies, the evaluation of combination strategies with radiotherapy, chemotherapy, or targeted drugs is ongoing. The results of clinical trials with dabrafenib and trametinib led to the approval from FDA of this combination for patients with BRAF V600E mutated ATC with locally advanced, unresectable, or metastatic ATC. The anti-PD-L1 antibody immunotherapy, alone or combined with a BRAF inhibitor, has been shown also promising in the treatment of ATC. Furthermore, to increase the therapeutic success and not to use ineffective or even harmful treatments, a real tailored therapy should be pursued, and this can be achieved thanks to the new available genomic analysis methods and to the possibility to test in vitro novel treatments directly in primary cells from each ATC patient. Exploring new treatment strategies is mandatory to improve the survival of these patients, guaranteeing a good quality of life.

Thyroid volumes and serum VEGF levels in dyslipidemic patients: effects of statin treatment

Background/aim

Defective vascularization may be important in thyroid nodular disease. In this study, we aimed to investigate serum vascular endothelial growth factor (VEGF) levels in dyslipidemic patients with thyroid nodules, as well as the effects of statin therapy.

Materials and methods

The study included 37 dyslipidemic patients with thyroid nodules and 32 dyslipidemic patients without thyroid nodules. Anthropometry, serum VEGF levels, biochemical parameters, thyroid-stimulating hormone (TSH), free triiodothyronine (fT3) and free thyroxine (fT4) levels, and thyroid sonography were determined before and after 6 months of statin therapy.

Results

Patients with and without thyroid nodules had similar metabolic parameters. Serum VEGF levels did not differ between the groups. In patients with nodules, VEGF levels remained unchanged (P = 0.931) after statin therapy. However, serum VEGF levels were lowered by statin treatment in patients without nodules (P = 0.030). Statin therapy resulted in a decrease in the dominant thyroid nodule volume. The changes in thyroid volume and dominant thyroid nodule volume were not correlated with changes in VEGF, body mass index, total cholesterol, low-density lipoprotein cholesterol, or homeostatic model assessment of insulin resistance (HOMA-IR).

Conclusion

Although statin treatment decreases serum VEGF levels in dyslipidemic patients without thyroid nodules, it has no lowering effect on serum VEGF levels in patients with thyroid nodules. The decrease in thyroid nodule volume with statin treatment was associated with neither metabolic parameters nor serum VEGF levels.

Phase 2 study of vascular endothelial growth factor trap for the treatment of metastatic thyroid cancer

BACKGROUND

Several multitargeted tyrosine kinase inhibitors (TKIs) have demonstrated activity in patients with thyroid cancer that is refractory to radioactive iodine (RAI). The antitumor effect is attributed at least in part to the ability of these TKIs to inhibit angiogenesis in these vascular tumors. Vascular endothelial growth factor (VEGF) Trap (VT) is a recombinantly produced fusion protein consisting solely of human sequences for VEGF receptors 1 and 2 extracellular domains and human immunoglobulin 1. Evaluating VT in patients with thyroid cancer is reasonable considering the activity observed with TKIs targeting VEGF.

METHODS

The current study was a single-institution, phase 2, Simon 2-stage design (21 to >41 patients) study based on the objective response rate and/or 6-month progression-free survival as the primary endpoints. Eligible patients were required to have progressive, RAI-refractory and/or [¹⁸ F]fludeoxyglucose-avid, recurrent and/or metastatic, nonmedullary, nonanaplastic thyroid cancer; disease that was measurable using Response Evaluation Criteria In Solid Tumors (RECIST) criteria; and adequate organ and bone marrow function. VT at a dose of 4 mg/kg intravenously was administered every 14 days.

RESULTS

A total of 40 patients were included in the analysis. Of these patients, 24 had papillary thyroid cancer, 2 had follicular thyroid cancer, and 11 had Hurthle cell thyroid cancer. The final 3 tumors were classified as poorly differentiated. There were no complete and/or partial responses noted; 34 patients achieved stable disease and 6 patients experienced disease progression as their best response. Of the 34 patients with stable disease, 16 remained on the study for >6 months and 6 patients remained on the study for >12 months. The median duration on treatment was 4.1 months (range, 0.6-30.8 months).

CONCLUSIONS

Unlike TKIs, which have shown responses in this setting, to the authors' knowledge there have been no responses observed with the use of single-agent VT to date. It does not appear to be a promising drug for the treatment of patients with thyroid cancer.

The roles and role-players in thyroid cancer angiogenesis

Thyroid cancer is the most prevalent endocrine cancer worldwide. Angiogenesis, the formation of new blood vessels, plays a pivotal role in the development and progression of tumors. Over the past years, cancer research has focused on the ability of tumors to induce newly formed blood vessel, because tumor growth and the process of cancer metastasis mainly depends on angiogenesis. Tumor neovascularization occurs following the imbalance between pro-angiogenic and anti-angiogenic factors until the tumor switches to an angiogenic phenotype. A number of signaling factors and receptors that are implicated in the regulation of angiogenesis have been identified and characterized; most notably, the vascular endothelial growth factors (VEGFs) family and their receptors, which are the main pro-angiogenic molecules during early development and in pathological conditions such as cancer. Although thyroid is a highly vascularized organ, angiogenic switch in tumors of this organ leads to the formation of a vast network of blood vessels that favors the dissemination of tumor cells to distant organs and results in deterioration of patient conditions. Accordingly, the identification of key angiogenic biomarkers for thyroid cancer can facilitate diagnosis, prognosis and clinical decision-making and also may help to discover targeting factors for effective cancer therapy as well as monitoring response to therapy. Hence, the main purposes of this review are to summarize the types and mechanisms of angiogenesis emphasizing the prominent factors implicated in thyroid cancer angiogenesis.

Expression of Vascular Endothelial Growth Factor and Its Receptors in Thyroid Nodular Hyperplasia and Papillary Thyroid Carcinoma: A Tertiary Health Care Centre Based Study

Introduction:

Vascular endothelial growth factor (VEGF) is an angiogenic factor that plays an important role in thyroid cancer. VEGF is known to have high affinity to VEGF receptors such as VEGFR-1 (Flt-1) and VEGFR-2 (KDR). Papillary thyroid carcinoma (PTC) is the most common thyroid cancer and studies showed the increasing incidence of PTC arising in nodular hyperplasia. Targeted therapy on these growth factors and receptors are used in management of both differentiated and undifferentiated thyroid carcinoma. This study aims to determine the expression of VEGF and VEGF receptors (VEGFR) in thyroid nodular hyperplasia and PTC.

Methods:

A cross-sectional study based on paraffinized archival tissue blocks of 113 nodular hyperplasias and 67 PTC from the thyroidectomy specimens in the year of 2003 to 2014. The tissue sections were then stained by immunohistochemistry for VEGF, VEGFR-1 and VEGFR-2. The lymph node involvement and extrathyroid extension also were determined.

Results:

The mean age of PTC patients was 44.7±15.8 years and nodular hyperplasia were 42.2±13.6 years. There was a statistical difference of VEGFR-1 (p=0.028) and VEGFR-2 (p=0.003) expression between nodular hyperplasia and PTC. However, no significant difference of VEGF expression (p=0.576) between both diseases. Co-expression of VEGF and VEGFR-1 was significant in both nodular hyperplasia (p=0.016) and PTC (p=0.03), meanwhile no relevant relationship for VEGF and VEGFR-2 expression (p>0.05). No significant association (p>0.05) between lymph node status and extrathyroid extension with age groups, gender, VEGF and VEGFR expression.

Conclusions:

VEGF, VEGFR-1 and VEGFR-2 showed overexpression in both nodular hyperplasia and PTC. The expression of VEGFR-1 and VEGFR-2 are more significant in PTC with relevant co-expression of VEGF and VEGFR-1. Therefore, the inhibition of VEGFR offers a promising prospect for tumour management in thyroid carcinoma.

Intraoperative radiotherapy for the treatment of thyroid cancer: a pilot study

We preliminarily evaluated the clinical feasibility and efficacy of intraoperative radiotherapy in patients with thyroid carcinoma. Nine thyroid cancer patients received intraoperative radiotherapy using an Intrabeam system. The dose was 3-4 Gy and the irradiation time ranged from 1 min 32 s to 7 min 33s. One case was a primary thyroid carcinoma, while the other cases were recurrent disease. Adverse effects, recurrence and survival were analyzed. In one patient, poorly differentiated thyroid carcinoma recurred 5 months after treatment, one patient developed a postoperative tracheal skin fistula, and one patient developed a wound infection. Because the affected areas were treated with both surgical resection and then radiotherapy, it is difficult to know which of those led to the adverse effects. Nonetheless, our results indicate that intraoperative radiotherapy can relieve the symptoms associated with thyroid cancer and improve the quality of life for these patients. It thus appears feasible to treat thyroid cancer patients with intraoperative radiotherapy.

THE CORRELATION BETWEEN INFLAMMATORY AND METABOLIC PARAMETERS WITH THYROID FUNCTION IN PATIENTS WITH HASHIMOTO'S THYROIDITIS: THE POTENTIAL ROLE OF INTERLEUKIN 23 (IL-23) AND VASCULAR ENDOTHELIAL GROWTH FACTOR (VEGF) - 1

CONTEXT

Hashimoto's thyroiditis is the most common autoimmune disorder as cause of secondary hypothyroidism. The disease is associated with several metabolic disturbances and inflammatory disorders.

OBJECTIVES

The aim of the current report was to evaluate several inflammatory and metabolic predictors of Hashimoto's thyroiditis.

SUBJECTS AND METHODS

In the current study, forty patients with Hashimoto's thyroiditis participated in the current study. They were aged between 20 to 50 years old. Anthropometric and nutritional measurements were assessed and biochemical factors including serum VEGF, IL-23, Nesfatin-1 and serum lipids were measured.

RESULTS

Waist circumference was higher among patients with lower serum TSH concentrations. Serum HDL and T4 concentrations were lower and serum IL-23 was higher among patients with higher TSH concentrations. BMI, WC and serum HDL were negative predictors of serum TSH while IL-23 was positively associated with TSH concentrations. Serum lipids including TC, TG and LDL were also negatively associated with T3 and T4 concentrations.

CONCLUSIONS

According to our findings, VEGF and serum IL-23 were potent predictors of Hashimoto's thyroiditis. However, further studies are warranted to better clarify these associations and underlying pathologic mechanisms.

IL13Rα2 siRNA inhibited cell proliferation, induced cell apoptosis, and suppressed cell invasion in papillary thyroid carcinoma cells

Aim

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Infiltrative growth and metastasis are the two most intractable characteristics of PTC. Interleukin-13 receptor α2 (IL13Rα2) with high affinity for Th2-derived cytokine IL-13 has been reported to be overexpressed in several tumors. In this study, an analysis of IL13Rα2 expression in PTC and matched paracancerous tissues was undertaken, and its biologic functions in PTC were assessed.

Methods

IL13Rα2 and vascular endothelial growth factor (VEGF) expression were detected by using real-time polymerase chain reaction and immunohistochemistry analyses. Cell proliferation, invasion, apoptosis, and caspase activity were measured with the Cell Counting Kit-8, Transwell, flow cytometry analyses, and biochemistry assay, respectively.

Results

Upregulation of IL13Rα2 and VEGF was observed in PTC tissues compared with matched paracancerous tissues. Pearson’s correlation analysis indicated that IL13Rα2 mRNA level in the tested PTC tissues was positively correlated with VEGF mRNA level. Besides, inhibited cell proliferation, induced cell apoptosis, and suppressed cell invasion were detected in IL13Rα2-silenced TPC-1 cells. Increased activity of Caspase 3 and Caspase 9, along with elevated cleaved Caspase 3 and poly (ADP)-ribose polymerase indicated the signal pathway of cell apoptosis induced by IL13Rα2 siRNA. In addition, downregulated metastasis- and angiogenesis-related proteins VEGF, VEGFR2, MMP2, and MMP9 indicated the decreased number of invading cells after knockdown of IL13Rα2.

Conclusion

The results demonstrate that IL13Rα2 plays an important role in the progress of PTC. IL13Rα2 knockdown in PTC cells inhibited cell proliferation, induced cell apoptosis, and suppressed cell invasion. These data suggest that IL13Rα2 may be a novel therapeutic target in the treatment of PTC clinically.

Novel therapies against aggressive differentiated thyroid carcinomas

The incidence of thyroid cancer (TC) is increasing. Although the majority of these cancers have a good prognosis, 10% of these will develop local recurrence and/or distant metastases. Conventional cytotoxic chemotherapy has been largely replaced by molecular-target therapies, but it can still have a role. Two tyrosine kinase inhibitors have been approved for the treatment of advanced differentiated TC. They significantly improve progression-free survival, but at the cost of frequent and potentially serious adverse effects. At the moment, there are multiple clinical trials with other tyrosine kinase inhibitors and other drugs. We present a review of the current standard of care and what is up to come in the treatment of advanced TC.

Relationship between expression of vascular endothelial growth factor and cervical lymph node metastasis in papillary thyroid cancer: A meta-analysis

The aim of the present study was to examine the relationship between the protein expression of vascular endothelial growth factor (VEGF) and lymph node metastasis (LNM) in papillary thyroid cancer (PTC). VEGF-related articles that had been published until August 2016 were searched from the PubMed, EMBASE, and MEDLINE to identify the risk factors of LNM in PTC. RevMan 5.3 software was used for the meta-analysis. Finally, 9 articles met the inclusion criteria and were included in our meta-analysis. LNM was found to be present in 176 of 318 patients (57.8%) with high VEGF expression and in 71 of 159 patients (47.0%) with low VEGF expression. The overall OR was 2.81 (95% confidence interval, 1.49-5.29). LNM occurred more frequently in patients with high VEGF expression than in those with low VEGF expression (P=0.001). Heterogeneity was markedly decreased in the subgroup analyses of LNM in terms of the patients' country of origin and the detection methods. Our meta- analysis concluded that the VEGF protein expression is associated with LNM in PTC.

Treatment and surveillance of advanced, metastatic iodine-resistant differentiated thyroid cancer

PURPOSE OF REVIEW

This review will focus on the management and treatment of metastatic thyroid cancer that is radioactive iodine refractory and review the new drugs and their mechanism of actions as well as their adverse events.

RECENT FINDINGS

Until recently, there were no efficacious therapeutic modalities for these patients. With advancement in knowledge and research of the molecular aberrations and oncogenic mutations in thyroid cancer as well as further understanding the role of angiogenesis in tumor growth molecular pathogenesis, novel targeted therapies are available for these patients. Some of these drugs have successfully prolonged progression free survival and are now Food and Drug Administration approved. Additional agents are approved for the treatment of other types of cancers and are currently under investigation for differentiated thyroid cancer treatment.

SUMMARY

Differentiated thyroid cancer (papillary and follicular) is the most common endocrine malignancy. It is generally known to have an excellent prognosis and patients are usually cured with the conventional primary treatments including surgery, radioactive iodine, and thyroid stimulating hormone suppression. A minor proportion of patients do not fully recover mainly because they develop radioactive iodine-resistant disease. These patients have few treatment options, which we aimed to describe here.

Novel treatment options for anaplastic thyroid cancer

Several genetic alterations have been identified in different molecular pathways ofanaplastic thyroid cancer (ATC) and associated with tumor aggressiveness and progression (BRAF, p53,RAS, EGFR, VEGFR-1, VEGFR-2, etc). New drugs targeting these molecular pathways have beenrecently evaluated in ATC. Areas covered: We review the new targeted therapies of ATC. Interesting results have been reported with molecules targeting different pathways, as: a-BRAF (dabrafenib/trametinib, vemurafenib); b-angiogenesis (sorafenib, combretastatin, vandetanib, sunitinib, lenvatinib, CLM3, etc); c-EGFR (gefitinib); d- PPARγ agonists (rosiglitazone, pioglitazone, efatutazone). In patients with ATC treated with lenvatinib, a median overall survival of 10.6 (3.8-19.8) months was reported. In order to bypass the resistance to the single drug, the capability of targeted drugs to synergize with radiation, or chemotherapy, or other targeted drugs is explored. Expert commentary: New, affordable and individual genomic analysis combined with the opportunity to test these new treatments in primary cell cultures from every ATC patient in vitro, may permit the personalization of therapy. Increasing the therapeutic effectiveness and avoiding the use of ineffective drugs. The identification of new treatments is necessary, to extend life duration guaranteing a good quality of life. To bypass the resistance to asingle drug, the capability of targeted drugs to synergize with radiation, or chemotherapy, or othertargeted drugs is explored. Moreover, new affordable individual genomic analysis and the opportunity totest these novel treatments in primary cell cultures from every ATC patient in vitro, might permit topersonalize the therapy, increasing the therapeutic effectiveness and avoiding the use of ineffectivedrugs.

The effects of Nigella sativa on thyroid function, serum Vascular Endothelial Growth Factor (VEGF) - 1, Nesfatin-1 and anthropometric features in patients with Hashimoto's thyroiditis: a randomized controlled trial

Background

Hashimoto’s thyroiditis is an autoimmune disorder and the most common cause of hypothyroidism. The use of Nigella sativa, a potent herbal medicine, continues to increase worldwide as an alternative treatment of several chronic diseases including hyperlipidemia, hypertension and type 2 diabetes mellitus (T2DM). The aim of the current study was to evaluate the effects of Nigella sativa on thyroid function, serum Vascular Endothelial Growth Factor (VEGF) – 1, Nesfatin-1 and anthropometric features in patients with Hashimoto’s thyroiditis.

Methods

Forty patients with Hashimoto’s thyroiditis, aged between 22 and 50 years old, participated in the trial and were randomly allocated into two groups of intervention and control receiving powdered Nigella sativa or placebo daily for 8 weeks. Changes in anthropometric variables, dietary intakes, thyroid status, serum VEGF and Nesfatin-1 concentrations after 8 weeks were measured.

Results

Treatment with Nigella sativa significantly reduced body weight and body mass index (BMI). Serum concentrations of thyroid stimulating hormone (TSH) and anti-thyroid peroxidase (anti-TPO) antibodies decreased while serum T3 concentrations increased in Nigella sativa-treated group after 8 weeks. There was a significant reduction in serum VEGF concentrations in intervention group. None of these changes had been observed in placebo treated group. In stepwise multiple regression model, changes in waist to hip ratio (WHR) and thyroid hormones were significant predictors of changes in serum VEGF and Nesgfatin-1 values in Nigella sativa treated group (P < 0.05).

Conclusions

Our data showed a potent beneficial effect of powdered Nigella sativa in improving thyroid status and anthropometric variables in patients with Hashimoto’s thyroiditis. Moreover, Nigella sativa significantly reduced serum VEGF concentrations in these patients. Considering observed health- promoting effect of this medicinal plant in ameliorating the disease severity, it can be regarded as a useful therapeutic approach in management of Hashimoto’s thyroiditis.

Trial registration

Iranian registry of clinical trials (registration number IRCT2015021719082N4- Registered March-15-2015).

Evolving molecularly targeted therapies for advanced-stage thyroid cancers

Increased understanding of disease-specific molecular targets of therapy has led to the regulatory approval of two drugs (vandetanib and cabozantinib) for the treatment of medullary thyroid cancer (MTC), and two agents (sorafenib and lenvatinib) for the treatment of radioactive- iodine refractory differentiated thyroid cancer (DTC) in both the USA and in the EU. The effects of these and other therapies on overall survival and quality of life among patients with thyroid cancer, however, remain to be more-clearly defined. When applied early in the disease course, intensive multimodality therapy seems to improve the survival outcomes of patients with anaplastic thyroid cancer (ATC), but salvage therapies for ATC are of uncertain benefit. Additional innovative, rationally designed therapeutic strategies are under active development both for patients with DTC and for patients with ATC, with multiple phase II and phase III randomized clinical trials currently ongoing. Continued effort is being made to identify further signalling pathways with potential therapeutic relevance in thyroid cancers, as well as to elaborate on the complex interactions between signalling pathways, with the intention of translating these discoveries into effective and personalized therapies. Herein, we summarize the progress made in molecular medicine for advanced-stage thyroid cancers of different histotypes, analyse how these developments have altered - and might further refine - patient care, and identify open questions for future research.

New insights in the treatment of radioiodine refractory differentiated thyroid carcinomas: to lenvatinib and beyond

During the past two decades, several key somatic mutations associated with development and progression of differentiated thyroid cancer (DTC) have been revealed. Historically, the treatment for advanced DTC is challenging after patients become refractory to radioactive iodine. The response to doxorubicin, the only chemotherapy agent approved by the US Food and Drug Administration, is disappointing either as monotherapy or combination therapy. Because of the lack of effective systemic treatment coupled with increased understanding of molecular and cellular pathogenesis, multiple kinase inhibitors (MKIs) as an alternative therapy for the treatment of advanced DTC has generated much interest, enthusiasm, and, most excitingly, promising results. After the encouraging results of these agents in earlier trials, the Food and Drug Administration approved sorafenib for the treatment of locally recurrent, progressive, or metastatic DTC refractory to radioactive iodine treatment based on the results of a multicenter DECISION trial. Sorafenib therefore became the first MKI approved for this indication in more than 20 years. However, even more impressive responses and progression-free survival benefits were seen in the phase III SELECT trial with lenvatinib, giving even higher hopes for the future management of what was considered just a decade ago an orphan disease. Given the role of MKIs, a new era in the treatment of advanced DTC has begun. We review the key therapeutic targets, oncogenic pathways, and promising clinical results of these agents in refractory disease, as well as their roles after failure of first line kinase inhibitors.

Lenvatinib in Advanced, Radioactive Iodine-Refractory, Differentiated Thyroid Carcinoma

Management options are limited for patients with radioactive iodine refractory, locally advanced, or metastatic differentiated thyroid carcinoma. Prior to 2015, sorafenib, a multitargeted tyrosine kinase inhibitor, was the only approved treatment and was associated with a median progression-free survival (PFS) of 11 months and overall response rate (ORR) of 12% in a phase III trial. Lenvatinib, a multikinase inhibitor with high potency against VEGFR and FGFR demonstrated encouraging results in phase II trials. Recently, the pivotal SELECT trial provided the basis for the FDA approval of lenvatinib as a second targeted therapy for these patients. Median PFS of 18.3 months in the lenvatinib group was significantly improved from 3.6 months in the placebo group, with an HR of 0.21 (95% confidence interval, 0.4-0.31; P < 0.0001). ORR was also significantly increased in the lenvatinib arm (64.7%) compared with placebo (1.5%). In this article, we will review the molecular mechanisms of lenvatinib, the data from preclinical studies to the recent phase III clinical trial, and the biomarkers being studied to further guide patient selection and predict treatment response.

Targeted therapies in advanced differentiated thyroid cancer

Differentiated thyroid cancer is the most common endocrine malignancy, and its incidence has been rising rapidly over the past 10 years. Although most patients with this disease have an excellent prognosis, a subset develops a more aggressive disease phenotype refractory to conventional therapies. Until recently, there was no effective therapy for these patients. With increasing knowledge of the molecular pathogenesis of thyroid cancer, novel targeted therapies are being developed for this group of patients. Sorafenib and lenvatinib, small-molecule multikinase inhibitors, were approved for the treatment of progressive, symptomatic, radioactive iodine refractory, advanced differentiated thyroid cancer in 2013 and 2015, respectively. This represents a major innovation in the therapy of patients with advanced thyroid cancer. However, these therapies still have many limitations and further research needs to be pursued with the ultimate goal of providing safe and effective personalized therapy for patients with advanced thyroid cancer.

Tyrosine kinase inhibitors for the therapy of anaplastic thyroid cancer

Anaplastic thyroid cancer (ATC) is often incurable so new therapeutic approaches are needed. Tyrosine kinases inhibitors (such as imanitib, sunitinib or sorafenib) are under evaluation for the treatment of ATC. Other vascular disrupting agents, such as combretastatin A4 phosphate, and antiangiogenic agents, such as aplidin, PTK787/ZK222584 and human VEGF monoclonal antibodies (bevacizumab, cetuximab), have been evaluated. Small-molecule adenosine triphosphate competitive inhibitors directed intracellularly at EGFRs tyrosine kinase, such as erlotinib or gefitinib, are also studied. Furthermore, new molecules have been shown to be active against ATC, such as CLM94 and CLM3. However, more research is needed to finally identify therapies able to control and to cure this disease.

A phase I study of cabozantinib (XL184) in patients with differentiated thyroid cancer

BACKGROUND

Cabozantinib targets tyrosine kinases including MET, vascular endothelial growth factor (VEGF) receptor 2, and rearranged during transfection (RET). Differentiated thyroid cancer (DTC) is a tumor type that may be sensitive to cabozantinib. Therefore, we evaluated cabozantinib in a cohort of heavily pretreated patients with metastatic DTC.

METHODS

This single-arm open-label phase I trial assessed the safety, tolerability, and antitumor activity of cabozantinib in DTC patients taking part in a drug-drug interaction study. Adult patients with histologically confirmed metastatic or surgically unresectable DTC (including papillary, follicular, or Hürthle cell) were enrolled. Patients received daily oral dosing of 140 mg cabozantinib. Safety was assessed by evaluation of adverse events (AEs), vital signs, electrocardiograms, laboratory tests, and concomitant medications. Tumor response by magnetic resonance imaging or computed tomography scan was investigator assessed using Response Evaluation Criteria In Solid Tumors (RECIST) v1.0.

RESULTS

The study enrolled 15 patients who had failed standard radioactive iodine therapy. Patients had received a median of two prior systemic agents, and 11 patients (73%) had previously received at least one VEGF pathway inhibiting therapy. Common AEs included diarrhea, nausea, fatigue, and decreased appetite. Partial response was reported in eight patients (53%). Median progression-free survival and median overall survival were not reached.

CONCLUSIONS

Cabozantinib demonstrates a safety profile similar to other multitargeted VEGFR inhibitors in advanced DTC patients. The antitumor activity observed in this study warrants further investigation of cabozantinib in patients with advanced DTC.

Personalization of targeted therapy in advanced thyroid cancer

Although generally the prognosis of differentiated thyroid carcinoma (DTC) is good, approximately 5% of people are likely to develop metastases which fail to respond to radioactive iodine, and other traditional therapies, exhibiting a more aggressive behavior. Nowadays, therapy is chosen and implemented on a watch-and-wait basis for most DTC patients. Which regimen is likely to work best is decided on the basis of an individual's clinical information, but only data referring to outcomes of groups of patients are employed. To predict the best course of therapy, an individual patient's biologic data is rarely employed in a systematic way. Anyway, the use of not expensive individual genomic analysis could lead us to a new era of patient-specific and personalized care. Recently, key targets that are now being evaluated in the clinical setting have been evidenced in the pathogenesis of these diseases. Some of the known genetic alterations playing a crucial role in the development of thyroid cancer include B-Raf gene mutations, rearranged during transfection/ papillary thyroid carcinoma gene rearrangements, and vascular endothelial growth factor receptor-2 angiogenesis pathways. The development of targeted novel compounds able to induce clinical responses and stabilization of disease has overcome the lack of effective therapies for DTC, which are resistant to radioiodine and thyroid stimulating hormone-suppressive therapy. Interestingly, the best responses have been demonstrated in patients treated with anti-angiogenic inhibitors such as vandetanib and XL184 in medullary thyroid cancer, and sorafenib in papillary and follicular DTC.

Metastatic mechanisms in follicular cell-derived thyroid cancer

Thyroid cancer incidence is rising annually largely related to enhanced detection and early stage well-differentiated primary tumors. The prognosis for patients with early stage thyroid cancer is outstanding with most patients being cured with surgery. In selected cases, I-131 is administered to treat known or suspected residual or metastatic disease. Even patients with loco-regional metastases typically have an outstanding long-term prognosis, albeit with monitoring and occasional intervention for residual or recurrent disease. By contrast, individuals with distant metastases from thyroid cancer, particularly older patients with larger metastatic burdens and those with poorly differentiated tumors, have a poor prognosis. Patients with metastatic anaplastic thyroid cancer have a particularly poor prognosis. Published clinical trials indicate that transient disease control and partial remissions can be achieved with kinase inhibitor therapy directed toward angiogenic targets and that in some cases I-131 uptake can be enhanced. However, the direct targets of activity in metastatic lesions are incompletely defined and clear evidence that these treatments increase the duration or quality of life of patients is lacking, underscoring the need for improved knowledge regarding the metastatic process to inform the development of new therapies. In this review, we will focus on current data and hypotheses regarding key regulators of metastatic dormancy, metastatic progression, and the role of putative cancer stem cells.

Relationship between preoperative serum TSH levels and expression of VEGF in papillary thyroid carcinoma

AIM

Vascular endothelial growth factor (VEGF) stimulates angiogenesis, increases vascular permeability and seems to correlate to aggressiveness of tumors. Increased expression of VEGF has been observed in papillary thyroid carcinoma (PTC). Thyroid stimulating hormone (TSH) is the major thyroid hormone, but its relationship with VEGF has seldom been studied. Therefore, we explored whether the immunohistochemical expression of VEGF was related to the serum TSH level.

METHODS

VEGF expression was analyzed in 43 archived PTC specimens using immunohistochemistry, with adjacent normal thyroid tissues used as controls. Serum TSH was measured by immunoradiometric assay before surgery and correlated to VEGF expression.

RESULTS

Positive VEGF expression was found in 90% of 43 PTC tissue specimens, but not in normal tissue. The serum TSH levels revealed a positive correlation with VEGF expression, R = 0.592 (P < 0.01).

CONCLUSIONS

TSH is a major thyroid hormone. Whether TSH promotes the progression of PTC is not known but the serum TSH levels reveal a positive correlation with VEGF expression.

An Ep-ICD based index is a marker of aggressiveness and poor prognosis in thyroid carcinoma

Background

Nuclear accumulation of the intracellular domain of epithelial cell adhesion molecule (Ep-ICD) in tumor cells was demonstrated to predict poor prognosis in thyroid carcinoma patients in our earlier study. Here, we investigated the clinical significance of Ep-ICD subcellular localization index (ESLI) in distinguishing aggressive papillary thyroid carcinoma (PTC) from non-aggressive cases.

Methods

Using domain specific antibodies against the intracellular (Ep-ICD) and extracellular (EpEx) domains of epithelial cell adhesion molecule, 200 archived tissues from a new cohort of patients with benign thyroid disease as well as malignant aggressive and non aggressive PTC were analyzed by immunohistochemistry (IHC). ESLI was defined as sum of the IHC scores for accumulation of nuclear and cytoplasmic Ep-ICD and loss of membranous EpEx; ESLI = [Ep-ICD_nuc + Ep-ICD_cyt + loss of membranous EpEx].

Results

For the benign thyroid tissues, non-aggressive PTC and aggressive PTC, the mean ESLI scores were 4.5, 6.7 and 11 respectively. Immunofluorescence double staining confirmed increased nuclear Ep-ICD accumulation and decreased membrane EpEx expression in aggressive PTC. Receiver-operating characteristic (ROC) curve analysis showed an area under the curve (AUC) of 0.841, 70.2% sensitivity and 83.9% specificity for nuclear Ep-ICD for differentiating aggressive PTC from non-aggressive PTC. ESLI distinguished aggressive PTC from non-aggressive cases with improved AUC of 0.924, 88.4% sensitivity and 85.5% specificity. Our study confirms nuclear accumulation of Ep-ICD and loss of membranous EpEx occurs in aggressive PTC underscoring the potential of Ep-ICD and ESLI to serve as diagnostic markers for aggressive PTC. Kaplan Meier survival analysis revealed significantly reduced disease free survival (DFS) for ESLI positive (cutoff >10) PTC (p<0.05), mean DFS = 133 months as compared to 210 months for patients who did not show positive ESLI.

Conclusion

ESLI scoring improves the identification of aggressive PTC and thereby may serve as a useful index for defining aggressiveness and poor prognosis among PTC patients.

Relationships between Lymph Node Metastasis and Expression of CD31, D2-40, and Vascular Endothelial Growth Factors A and C in Papillary Thyroid Cancer

OBJECTIVES

To investigate the relationships between lymph node metastasis (LNM) and expression of CD31, D2-40 and vascular endothelial growth factors (VEGF)-A and -C in patients with papillary thyroid cancer (PTC).

METHODS

Paraffin-embedded thyroid tissues of 72 patients were evaluated, which included 25 patients with thyroid nodular hyperplasia (TNH), 24 PTC patients without LNM, and 23 PTC patients with LNM. Three pathologists, who were blinded to the patient's clinical information, assessed the immunohistochemical staining results. The amount of expression was scored as high (>25% of cells stained) or low (0-25%).

RESULTS

A higher level of VEGF-A expression was observed in the PTC groups regardless of LNM when compared to the group with TNH (91.3%, 79.2%, 4.0%, respectively). VEGF-C expression in the PTC with LNM group was significantly higher than the other two groups (P<0.05). No difference in microvessel density (MVD) scores was observed using CD31 among the three groups. The lymphatic vessel density (LVD) score using D2-40 was significantly higher in patients having PTC with LNM than the other groups (P<0.05).

CONCLUSION

VEGF-C and D2-40 were more highly expressed in patients having PTC with LNM than in patients having PTC without LNM or in those having TNH. Analysis of VEGF-C level and LVD using D2-40 may be helpful in the diagnosis of PTC and the evaluation of LNM potential in patients with PTC.

Emerging role of multikinase inhibitors for refractory thyroid cancer

Thyroid cancer incidence continues to increase, remaining the most common endocrine malignancy. The need for effective systemic therapies combined with high incidence of driver mutations and overexpression of molecular pathways make refractory thyroid cancer an ideal candidate for treatment with novel agents. Multikinase inhibitors have caused a paradigm shift in the treatment of patients with advanced iodine-refractory thyroid cancer. These agents have shown to be the most effective systemic therapy for this disease not only causing prolonged responses but also improving survival. The activity of these agents inhibiting several pathways simultaneously, such as rearranged during transfection protooncogene, mitogen-activated protein kinase, and angiogenesis, can probably explain the effectiveness in controlling the progression of this malignancy. Several of these agents are currently on clinical studies in patients with differentiated and medullary thyroid cancer and most of them are showing promising clinical activity. With the approval of vandetanib for the treatment of medullary thyroid cancer, a new era in the management of this disease has begun. The molecular rationale for the use of these drugs for thyroid cancer is discussed as well as their promising clinical results.

Biotinidase is a novel marker for papillary thyroid cancer aggressiveness

Biotinidase was identified in secretome analysis of thyroid cancer cell lines using proteomics. The goal of the current study was to analyze the expression of biotinidase in thyroid cancer tissues and fine needle aspiration (FNA) samples to evaluate its diagnostic and prognostic potential in thyroid cancer. Immunohistochemical analysis of biotinidase was carried out in 129 papillary thyroid cancer (PTC, 34 benign thyroid tissues and 43 FNA samples and correlated with patients' prognosis. Overall biotinidase expression was decreased in PTC compared to benign nodules (p = 0.001). Comparison of aggressive and non-aggressive PTC showed decrease in overall biotinidase expression in the former (p = 0.001). Loss of overall biotinidase expression was associated with poor disease free survival (p = 0.019, Hazards ratio (HR) = 3.1). We examined the effect of subcellular compartmentalization of nuclear and cytoplasmic biotinidase on patient survival. Decreased nuclear expression of biotinidase was observed in PTC as compared to benign tissues (p<0.001). Upon stratification within PTC, nuclear expression was reduced in aggressive as compared to non-aggressive tumors (p<0.001). Kaplan-Meier survival analysis showed significant association of loss of nuclear biotinidase expression with reduced disease free survival (p = 0.014, HR = 5.4). Cytoplasmic biotinidase expression was reduced in aggressive thyroid cancers in comparison with non-aggressive tumors (p = 0.002, Odds ratio (OR) = 0.29) which was evident by its significant association with advanced T stage (p = 0.003, OR = 0.28), nodal metastasis (p<0.001, OR = 0.16), advanced TNM stage (p<0.001, OR = 0.21) and extrathyroidal extension (p = 0.001, OR = 0.23). However, in multivariate analysis extrathyroidal extension emerged as the most significant prognostic marker for aggressive thyroid carcinomas (p = 0.015, HR = 12.8). In conclusion, loss of overall biotinidase expression is a novel marker for thyroid cancer aggressiveness.

Differentiated thyroid cancers: a comprehensive review of novel targeted therapies

Differentiated thyroid carcinoma (DTC) accounts for more than 90% of new thyroid cancer diagnoses, and includes papillary, follicular and Hürthle cell carcinoma. The prognosis for the vast majority of individuals diagnosed with DTC is excellent, with current treatment that includes surgery, radioactive iodine ablation and postoperative thyroid-stimulating hormone suppression. Unfortunately, the small proportion of individuals who develop radioactive iodine-resistant recurrent disease have few treatment options, and the vast majority will eventually die from their disease. Recently, several novel targets for anticancer agents have been identified and offer new hope for thyroid cancer patients diagnosed with progressive disease. In addition to targeting genes commonly altered in thyroid cancer, which include mutations in BRAF, RAS and RET, proangiogenic growth factor receptors and the sodium-iodide symporter have also been targeted. Several clinical trials evaluating tyrosine kinase and angiogenesis inhibitors for treatment of individuals diagnosed with metastatic or treatment-refractory DTC are currently underway. The objective of this review is to evaluate recent clinical trials that have studied novel targeted drugs for treatment of DTC.

Differentiated thyroid cancer: management of patients with radioiodine nonresponsive disease

Differentiated thyroid carcinoma (papillary and follicular) has a favorable prognosis with an 85% 10-year survival. The patients that recur often require surgery and further radioactive iodine to render them disease-free. Five percent of thyroid cancer patients, however, will eventually succumb to their disease. Metastatic thyroid cancer is treated with radioactive iodine if the metastases are radioiodine avid. Cytotoxic chemotherapies for advanced or metastatic noniodine avid thyroid cancers show no prolonged responses and in general have fallen out of favor. Novel targeted therapies have recently been discovered that have given rise to clinical trials for thyroid cancer. Newer aberrations in molecular pathways and oncogenic mutations in thyroid cancer together with the role of angiogenesis in tumor growth have been central to these discoveries. This paper will focus on the management and treatment of metastatic differentiated thyroid cancers that do not take up radioactive iodine.

Sunitinib exerts only limited effects on the proliferation and differentiation of anaplastic thyroid cancer cells

BACKGROUND

Novel molecularly targeted drugs are undergoing preclinical and clinical testing to assess their efficacy against refractory thyroid carcinomas. The multikinase inhibitor Sunitinib has been shown to inhibit the kinase activity of the RET oncogene and reduce proliferation in differentiated thyroid cancer cells harboring the RET/PTC rearrangement. In this study, we evaluated its effects in human cell lines derived from differentiated (TPC-1) and anaplastic (8505C, CAL-62, and C643) thyroid cancers.

METHODS

The cells exposed to various concentrations of Sunitinib were examined for: (1) cell viability and presence of apoptosis, analyzed by cell counts, MTT assay, trypan blue exclusion assay, western blotting, and immunofluorescence; (2) expression of cyclin D1 and phosphorylated and nonphosphorylated extracellular signal-regulated kinase (ERK) and Akt proteins, analyzed by western blotting; and (3) transcription of genes encoding thyrocyte differentiation markers (thyroid-stimulating hormone receptor, sodium/iodide symporter, thyroglobulin, and thyroperoxidase) and proangiogenic factors (vascular endothelial growth factor A, platelet-derived growth factors A and B), measured by quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Exposure to nanomolar concentrations of Sunitinib significantly reduced cell viability in only TPC-1 cells, and this effect was paralleled by reduction of cyclin D1 levels. Western blotting revealed reduced phosphorylation of ERK and Akt after 3 and 6 hours of drug exposure. In contrast, the growth of 8505C, CAL-62, and C-643 cells was significantly reduced only by micromolar concentrations of Sunitinib, mainly due to induced necrotic rather than apoptotic death. In these cells, Sunitinib exerted a few significant effects on the transcription of angiogenic factors or thyrocyte differentiation markers.

CONCLUSIONS

Sunitinib has little or no effect on the growth or differentiation of anaplastic thyroid cancer cells, thus suggesting that it is unlikely to be effective in the treatment of anaplastic thyroid cancer.

Epigenetics modifications and therapeutic prospects in human thyroid cancer

At present no successful treatment is available for advanced thyroid cancer, which comprises poorly differentiated, anaplastic, and metastatic or recurrent differentiated thyroid cancer not responding to radioiodine. In the last few years, biologically targeted therapies for advanced thyroid carcinomas have been proposed on the basis of the recognition of key oncogenic mutations. Although the results of several phase II trials look promising, none of the patients treated had a complete response, and only a minority of them had a partial response, suggesting that the treatment is, at best, effective in stabilizing patients with progressive disease. "Epigenetic" refers to the study of heritable changes in gene expression that occur without any alteration in the primary DNA sequence. The epigenetic processes establish and maintain the global and local chromatin states that determine gene expression. Epigenetic abnormalities are present in almost all cancers and, together with genetic changes, drive tumor progression. Various genes involved in the control of cell proliferation and invasion (p16INK4A, RASSF1A, PTEN, Rap1GAP, TIMP3, DAPK, RARβ2, E-cadherin, and CITED1) as well as genes specific of thyroid differentiation (Na+/I- symport, TSH receptor, pendrin, SL5A8, and TTF-1) present aberrant methylation in thyroid cancer. This review deals with the most frequent epigenetic alterations in thyroid cancer and focuses on epigenetic therapy, whose goal is to target the chromatin in rapidly dividing tumor cells and potentially restore normal cell functions. Experimental data and clinical trials, especially using deacetylase inhibitors and demethylating agents, are discussed.

Evolving strategies: future treatment of glioblastoma

Despite recent advances, there remains an unmet need for more effective treatments for newly diagnosed and recurrent glioblastoma (GBM). While currently available alkylator-based and antiangiogenic agents provide some efficacy, novel antiangiogenic and antiglioma treatments that provide enhanced efficacy with improvements in overall survival, the potential to overcome drug resistance and decreased treatment-related toxicity are still needed. Although VEGF-directed angiogenesis is critical during GBM pathogenesis, alternative proangiogenic and glioma-promoting pathways also play a key role in tumor progression. This article reviews the limitations of current GBM treatment, the importance of angiogenic signaling pathways in GBM pathogenesis and the preliminary results of novel antiangiogenic-targeted treatments being evaluated in GBM. Therapies that inhibit multiple glioma signaling pathways, including angiogenesis, have the possibility for further improving outcome in GBM and may represent the best option for increasing overall survival.

Thyroid cancer: pathogenesis and targeted therapy

Therapeutic options for advanced, unresectable radioiodine-resistant thyroid cancers have historically been limited. Recent progress in understanding the pathogenesis of the various subtypes of thyroid cancer has led to increased interest in the development of targeted therapies, with potential strategies including angiogenesis inhibition, inhibition of aberrant intracellular signaling in the MAPK and PI3K/AKT/mTOR pathways, radioimmunotherapy, and redifferentiation agents. On the basis of a recent positive phase III clinical trial, the RET, vascular endothelial growth factor receptor (VEGFR), and epidermal growth factor receptor (EGFR) inhibitor vandetanib has received FDA approval as of April 2011 for use in the treatment of advanced medullary thyroid cancer. Several other recent phase II clinical trials in advanced thyroid cancer have demonstrated significant activity, and multiple other promising therapeutic strategies are in earlier phases of clinical development. The recent progress in targeted therapy is already revolutionizing management paradigms for advanced thyroid cancer, and will likely continue to dramatically expand treatment options in the coming years.

BRAF(V600E) mutation and expression of proangiogenic molecular markers in papillary thyroid carcinomas

OBJECTIVE

Tyrosine kinase inhibitors (TKIs) are evaluated for treatment of radioiodine refractory thyroid cancer. Their effects in this setting are based on blockade of proangiogenic signaling mediated by receptors for vascular endothelial growth factors (VEGFs) and platelet-derived growth factors (PDGF). Most TKIs also block other cancer-relevant kinases, such as B-type Raf kinase (BRAF), which are constitutively activated in approximately half of papillary thyroid carcinomas (PTCs), but the impact of these effects is not clear.

DESIGN

The aim of our study was to investigate the impact of BRAF(V600E) on proangiogenic gene expression and microvascular features of PTCs.

METHODS

mRNA levels for VEGFA, VEGF receptors, and coreceptors (VEGFRs 1, 2, and 3, neuropilin-1), and PDGF receptor β (PDGFRβ or PDGFRB) were measured with real-time PCR in BRAF(V600E) (n=55) and wild-type BRAF (BRAF-wt; n=35) PTCs. VEGF and VEGFR protein expression and microvessel densities (MVD) and lymphatic vessel densities (LVDs) were assessed by immunohistochemistry in 22 of the 90 PTCs (including 11 BRAF(V600E) cases). Angiogenic gene expression was also studied in vitro after induction/silencing of the BRAF(V600E) mutation in thyrocyte lines.

RESULTS

Transcript levels of proangiogenic factors were significantly lower in BRAF(V600E) PTCs versus BRAF-wt PTCs (P<0.0001), but MVD and LVDs were not significantly different. VEGFA mRNA levels in thyroid cell lines decreased when BRAF(V600E) mutation was induced (P=0.01) and increased when it was silenced (P=0.01).

CONCLUSIONS

Compared with BRAF-wt PTCs, those harboring BRAF(V600E) exhibit downregulated VEGFA, VEGFR, and PDGFRβ expression, suggesting that the presence of BRAF mutation does not imply a stronger prediction of response to drugs targeting VEGF and PDGFB signaling pathways.

Targeted treatment of differentiated and medullary thyroid cancer

The incidence of thyroid cancer is increasing, with a concomitant increase in the number of patients with advanced and metastatic disease. Discoveries regarding the pathogenesis of thyroid cancer have led to the recent development of new therapeutic agents that are beginning to appear on the market. Many of these new agents are targeted kinase inhibitors primarily affecting oncogenic kinases (BRAF V600E, RET/PTC) or signaling kinases (VEGFR, PDGFR). Some of these agents report significant partial response rates, while others attain stabilization of disease as their best response. Their impact on survival is unclear. While these agents target similar pathways, a wide variety of differences exist regarding efficacy and side effect profile. Current expert opinion advises that these agents be used only in a specific subset of patients.

Hypoxia-inducible factor in thyroid carcinoma

Intratumoural hypoxia (low oxygen tension) is associated with aggressive disease and poor prognosis. Hypoxia-inducible factor-1 is a transcription factor activated by hypoxia that regulates the expression of genes that promote tumour cell survival, progression, metastasis, and resistance to chemo/radiotherapy. In addition to hypoxia, HIF-1 can be activated by growth factor-signalling pathways such as the mitogen-activated protein kinases- (MAPK-) and phosphatidylinositol-3-OH kinases- (PI3K-) signalling cascades. Mutations in these pathways are common in thyroid carcinoma and lead to enhanced HIF-1 expression and activity. Here, we summarise current data that highlights the potential role of both hypoxia and MAPK/PI3K-induced HIF-1 signalling in thyroid carcinoma progression, metastatic characteristics, and the potential role of HIF-1 in thyroid carcinoma response to radiotherapy. Direct or indirect targeting of HIF-1 using an MAPK or PI3K inhibitor in combination with radiotherapy may be a new potential therapeutic target to improve the therapeutic response of thyroid carcinoma to radiotherapy and reduce metastatic burden.

Novel molecular targeted therapies for refractory thyroid cancer

The incidence of thyroid cancer continues to increase and this neoplasia remains the most common endocrine malignancy. No effective systemic treatment currently exists for iodine-refractory differentiated or medullary thyroid carcinoma, but recent advances in the pathogenesis of these diseases have revealed key targets that are now being evaluated in the clinical setting. RET (rearranged during transfection)/PTC (papillary thyroid carcinoma) gene rearrangements, B-Raf gene mutations, and vascular endothelial growth factor receptor 2 (VEGFR-2) angiogenesis pathways are some of the known genetic alterations playing a crucial role in the development of thyroid cancer. Several novel agents have demonstrated promising responses. Of the treatments studied, multi-kinase inhibitors such as axitinib, sorafenib, motesanib, and XL-184 have shown to be the most effective by inducing clinical responses and stabilizing the disease process. Randomized clinical trials are currently evaluating these agents, results that may soon change the management of thyroid cancer.

Targeted therapies for thyroid tumors

Systemic chemotherapies for advanced or metastatic thyroid carcinomas have been of only limited effectiveness. For patients with differentiated or medullary carcinomas unresponsive to conventional treatments, novel therapies are needed to improve disease outcomes. Multiple novel therapies primarily targeting angiogenesis have entered clinical trials for metastatic thyroid carcinoma. Partial response rates up to 30% have been reported in single-agent studies, but prolonged disease stabilization is more commonly observed. The most successful agents target the vascular endothelial growth factor receptors, with potential targets including the mutant kinases associated with papillary and medullary oncogenesis. Two drugs approved for other malignancies, sorafenib and sunitinib, have had promising preliminary results reported, and are being used selectively for patients who do not qualify for clinical trials. At least one randomized, placebo-controlled phase III trial has been successfully completed, showing improved progression-free survival in patients with advanced or metastatic medullary thyroid carcinoma treated with vandetanib. Randomized trials for other agents are currently underway. Treatment for patients with metastatic or advanced thyroid carcinoma now emphasizes clinical trial opportunities for novel agents with considerable promise. Alternative options now exist for use of tyrosine kinase inhibitors that are well tolerated and may prove worthy of regulatory approval for this disease.