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Objective: Although the prognostic role of BRAFV600E mutation in papillary thyroid carcinoma (PTC) is controversial, the American Thyroid Association (ATA) includes the mutational status in their risk stratification system. To evaluate the impact of the BRAFV600E mutation status on PTC risk stratification. Subjects and methods: PTC patients attending a university-based hospital who had the analysis of the BRAFV600E mutation were included. Persistent disease was defined as the presence of biochemical or structural disease. The performance of the ATA risk stratification system on predicting persistent disease with or without the BRAFV600E mutation status information was evaluated. Results: Of the 134 patients evaluated, 44 (32.8%) carried BRAFV600E mutation. The median tumor size was 1.7 cm (P25-75 1.0-3.0), 64 (47.8%) patients had lymph node, and 11 (8.2%) distant metastases. According to the ATA risk stratification system, patients were classified as low, intermediate, and high risk in 55 (41%), 59 (44%), and 20 (14%) patients, respectively.The data on BRAFV600E mutation reclassified 12 (8.9%) patients from low to intermediate risk. After a median follow-up of 8.5 years, the prevalence of persistent disease was similar in patients with and without BRAFV600E mutation (P = 0.42). Multivariate analysis failed to demonstrate an association between the BRAFV600E mutation and persistent disease status (RR 0.96; 95%CI 0.47-1.94). Notably, none of the patients reclassified from low to intermediate risk showed persistent disease on follow-up. Conclusion: Inclusion of BRAFV600E mutational status has a limited impact on risk stratification and does not add to the prediction of outcomes in PTC patients. Arch Endocrinol Metab. 2020;64(6):751-7., SCOPUS: ar.j, info:eu-repo/semantics/published

Although the prognostic role of BRAFPTC patients attending a university-based hospital who had the analysis of the BRAFOf the 134 patients evaluated, 44 (32.8%) carried BRAFInclusion of BRAF

Elevated serum levels of carbohydrate antigen 19.9 (CA19.9), a well-established tumor marker in pancreatic neoplasms, has been proposed as a prognostic marker of tumor aggressiveness in medullary thyroid carcinoma (MTC). A hypothesis of C-cell dedifferentiation has been raised. Here, we evaluated the expression of CA19.9 and CD133, a stem cell marker, in MTC tissues. MTC samples from patients attending a university-based hospital were evaluated for CA19.9 and CD133 expression by immunohistochemistry. Clinical data were retrieved from medical records. Tumor specimens from 70 MTC patients (57.1% hereditary) were evaluated. The age at diagnosis was 36.1 ± 16.3 years, and 58.6% were female; 53% of patients had cervical and 20% distant metastases. CA19.9 staining was detected in 87% of the samples, but no association was observed with biochemical markers, tumor size, local or distant metastases (All P > 0.05). Remarkable, CA19.9 expression was higher in the metastasis than in primary tumor samples (P = 0.0002). CD133 was expressed in 90.5% samples, but no correlation was found with CA19.9. Interestingly, we identified three distinct expression patterns to CA19.9: individual, focal, and diffuse cells. Sporadic MTC was associated with the individual cell pattern (70.6%), while the hereditary form with the focal expression pattern (63.9%; P = 0.04). Remarkably, the diffuse pattern was associated with larger tumor size and distant metastases (P = 0.032). The majority of samples stained for CA19.9, suggesting it is an MTC cell-intrinsic feature. Three distinct expression patterns were identified, which were associated with the hereditary or sporadic form, larger tumor size, and presence of metastases.

Background Changes in global DNA methylation have been suggested to cause genomic instability leading to increased risk of cancer. The accumulation of epigenetic changes is believed to contribute to tumorigenesis and dedifferentiation, but the effects of such changes in thyroid cancer are still yet defined. Objective To evaluate the global DNA methylation levels in thyroid cancer patients. Methods Total DNA was extracted from peripheral blood leukocytes of the medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) patients and the methylation pattern was evaluated using the Imprint Methylated DNA Quantification kit (Sigma-Aldrich). Results A total of 42 patients were analyzed (24 MTC, 12 PTC, and 6 controls). For MTC, the mean age was 41 ± 20 years, 54% were women and 12 cases were sporadic. The median calcitonin level at diagnosis was 1692 (637–8865), 65% of the MTC patients had local metastases and 23% distant metastases. For PTC, the median age was 43 ± 15 years, 58% were women and 50% had local metastases. The percentage of overall methylation differed according to the tumor subtype. Patients with MTC had a higher level of DNA methylation when compared to individuals with PTC (35 (24–48) vs. 17 (6.5–20.5); P = 0.002, respectively). Interestingly, among patients with MTC, individuals with the sporadic form of the disease had a higher level of methylation when compared to the hereditary form (25 (16–37) vs. 43 (33–52); P = 0.025, respectively). No association was observed between global methylation levels and clinical and/or oncological characteristics of the disease. Conclusion Global methylation levels were higher in MTC as compared to PTC patients. These results suggest the overall DNA methylation profile may be influenced by the histological subtype of thyroid cancer.

Purpose of review Medullary thyroid carcinoma (MTC) comprises approximately 4% of all malignant thyroid neoplasms. Although the majority of patients have a good prognosis, a subgroup of patients develops progressive disease and requires systemic therapy. Here, we focused on the current MTC therapeutic approaches and discussed the advantages and disadvantages of molecular targeted therapies. Recent findings Targeted molecular therapies that inhibit RET and other tyrosine kinase receptors involved in angiogenesis have been shown to improve progression-free survival in patients with advanced MTC. Two drugs, vandetanib and cabozantinib, have been approved for the treatment of progressive or symptomatic MTC, and several others have exhibited variable efficacy. No tyrosine kinase inhibitor has been shown to improve survival. Although no definitive recommendation can currently be made, cumulative data indicate that knowledge of the tumor mutational profile may facilitate improvements in targeted therapy for MTC. Summary Tyrosine kinase inhibitors are effective therapeutic agents for the treatment of progressive MTC. Nevertheless, it is not clear who will benefit the most from therapy, and the decision regarding when and how to initiate the treatment should be made based on the patient's medical history and tumor behavior. Hopefully, in the near future, molecular profiling of MTC can be used to determine the most effective molecular therapeutic target.

Introduction: Although frequently assumed to be age-related changes, vascular white matter lesions (WML) are sometimes found in young adults. Etiology is usually attributed to sporadic small vessel disease; nevertheless, genetic disorders may also be implicated. We aimed to characterize the population of young adults with vascular WML in Neurology outpatient clinics. Methods: Neurologists from 12 Portuguese hospitals were invited to include patients aged 18–55 years evaluated in consultation, with vascular WML on MRI, scoring II or III in the Fazekas scale. Central imaging validation was performed by 2 independent, blinded, Neuroradiologists. Demographic and clinical data were collected as well as results of investigations performed. Results: During 2 years, 77 patients were included (mean age 47.7 years). Vascular risk factors were present in 88.3% patients (hypertension in 53.2%) and previous history of stroke in 36.4%. Patients without history of stroke were younger (46.6 ± 7.2 vs. 49.6 ± 3.9 years, p = 0.045) and had fewer vascular risk factors (p < 0.001). They were more frequently females (87.8 vs. 46.4%, p < 0.001), and headache (30.6 vs. 3.6%, p = 0.007), contrary to focal symptoms (16.3 vs. 53.6%, p = 0.001), was the most frequent reason of referral. Etiological investigations performed differed between Neurologists. A genetic disorder was identified in 6 out of 58 patients (CADASIL n = 5; COL4A1 n = 1). Conclusion: Young adults with vascular WML evaluated in Neurology outpatient clinics concentrate in the oldest age groups. Vascular risk factors should be screened carefully in this population. Among patients without history of stroke, females largely outweigh males. Diagnostic investigations performed do not follow a standardized protocol.

Medullary thyroid carcinoma (MTC) is a rare type of tumor that originates from thyroid C cells and accounts for 2–4% of all malignant thyroid neoplasms. MTC may occur sporadically or be inherited, as part of the MEN 2 syndrome. Germline mutations of the RET (REarranged during Transfection) proto-oncogene cause hereditary cancer, whereas somatic RET mutations and, less frequently, RAS mutations have been described in sporadic MTC samples. Since early surgery with complete resection of tumor mostly determines the likelihood of attaining cure for MTC, the broader use of RET genetic screening has dramatically changed the prognostic of gene carriers in hereditary MTC. Nevertheless, despite recent advances, the management of advanced, progressive MTC remains challenging. The multikinase inhibitors (MKI), vandetanib and cabozantinib, were approved for the treatment of progressive or symptomatic MTC, and several other compounds have exhibited variable efficacy. Although these drugs have been shown to improve progression-free survival, no MKI has been shown to increase the overall survival. As these drugs are nonselective, significant off-target toxicities may occur, limiting achievement of the required TK-specific inhibition. Recently, next-generation small-molecule TKI has been developed. These TKI are specifically designed for highly potent and selective targeting of oncogenic RET alterations, making them promising drugs for the treatment of advanced MTC. Here, we summarize the current understanding of the intracellular signaling pathways involved in MTC pathogenesis as well as the therapeutic approaches and challenges for the management of advanced MTC, focusing on targeted molecular therapies.

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazilian centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome.

© 2019 Elsevier Ltd. All rights reserved., Background: Multiple endocrine neoplasia type 2B is a rare syndrome caused mainly by Met918Thr germline RET mutation, and characterised by medullary thyroid carcinoma, phaeochromocytoma, and extra-endocrine features. Data are scarce on the natural history of multiple endocrine neoplasia type 2B. We aimed to advance understanding of the phenotype and natural history of multiple endocrine neoplasia type 2B, to increase awareness and improve detection. Methods: This study was a retrospective, multicentre, international study in patients carrying the Met918Thr RET variant with no age restrictions. The study was done with registry data from 48 centres globally. Data from patients followed-up from 1970 to 2016 were retrieved from May 1, 2016, to May 31, 2018. Our primary objectives were to determine overall survival, and medullary thyroid carcinoma-specific survival based on whether the patient had undergone early thyroidectomy before the age of 1 year. We also assessed remission of medullary thyroid carcinoma, incidence and treatment of phaeochromocytoma, and the penetrance of extra-endocrine features. Findings: 345 patients were included, of whom 338 (98%) had a thyroidectomy. 71 patients (21%) of the total cohort died at a median age of 25 years (range

Background: Papillary thyroid carcinoma (PTC) is the most common and less aggressive thyroid cancer, but some patients may display locally advanced disease. Therapeutic options are limited in these cases, particularly for those patients with unresectable tumors. Neoadjuvant therapy is not part of the recommended work up. Methods: Report a case of an unresectable grossly locally invasive PTC successfully managed with neoadjuvant therapy and provide a systematic review (SR) using the terms “Neoadjuvant therapy” AND “Thyroid carcinoma.” Results: A 32-year-old man with a 7.8 cm (in the largest dimension) PTC was referred to total thyroidectomy, but tumor resection was not feasible due to extensive local invasion (trachea, esophagus, and adjacent structures). Sorafenib, a multikinase inhibitor (MKI), was initiated; a 70% tumor reduction was observed after 6 months, allowing new surgical intervention and complete resection. Radioactive iodine (RAI) was administered as adjuvant therapy, and whole body scan (WBS) shows uptake on thyroid bed. One-year post-surgery the patient is asymptomatic with a status of disease defined as an incomplete biochemical response. The SR retrieved 123 studies on neoadjuvant therapy use in thyroid carcinoma; of them, 6 were extracted: 4 case reports and 2 observational studies. MKIs were used as neoadjuvant therapy in three clinical cases with 70–84% of tumor reduction allowing surgery. Conclusion: Our findings, along with other reports, suggest that MKIs is an effective neoadjuvant therapy and should be considered as a therapeutic strategy for unresectable grossly locally invasive thyroid carcinomas.

Type 3 deiodinase (DIO3, D3) is reactivated in human neoplasias. Increased D3 levels in papillary thyroid carcinoma (PTC) have been associated with tumor size and metastatic disease. The objective of this study is to investigate the signaling pathways involved inDIO3upregulation in PTC. Experiments were performed in human PTC cell lines (K1 and TPC-1 cells) or tumor samples.DIO3mRNA and activity were evaluated by real-time PCR and ion-exchange column chromatography respectively. Western blot analysis was used to determine the levels of D3 protein.DIO3gene silencing was performed via siRNA transfection.DIO3mRNA levels and activity were readily detected in K1 (BRAFV600E) and, at lower levels, in TPC-1 (RET/PTC1) cells (PP=0.02 respectively). Similarly,DIO3mRNA levels were higher in PTC samples harboring theBRAFV600Emutation as compared with those with RET/PTC1 rearrangement or negative for these mutations (PBRAFoncogene (PLX4032, 3 μM), MEK (U0126, 10–20 μM) or p38 (SB203580, 10–20 μM) signaling was associated with decreases inDIO3expression in K1 and TPC-1 cells. Additionally, the blockage of the sonic hedgehog (SHH) pathway by cyclopamine (10 μM) resulted in markedly decreases inDIO3mRNA levels. Interestingly, siRNA-mediatedDIO3silencing induced decreases on cyclin D1 expression and partial G1 phase cell cycle arrest, thereby downregulating cell proliferation. In conclusion, sustained activation of the MAPK and SHH pathways modulate the levels ofDIO3expression in PTC. Importantly,DIO3silencing was associated with decreases in cell proliferation, thus suggesting a D3 role in tumor growth and aggressiveness.

O carcinoma medular da tireoide (CMT) é um tumor maligno raro originário de células C parafoliculares da tireoide e corresponde a 4% das neoplasias malignas dessa glândula. O CMT apresenta-se como um tumor esporádico (75-80%) ou na forma hereditária (20-25%). O único tratamento curativo disponível no momento para o CMT é cirúrgico. No entanto, isso só é possível em casos em que o diagnóstico é realizado precocemente e a doença encontra-se restrita a glândula. Nos pacientes com doença avançada, onde as opções terapêuticas tradicionais como quimioterapia e radioterapia não são efetivas, os inibidores tirosino-quinase tem demonstrado eficácia na sobrevida livre de progessão da doença. Níveis de calcitonina sérica, um biomarcador específico para céluas C tireoideanas, e o antígeno-carcinoembrionário (CEA) são amplamente utilizados como marcadores no diagnóstico e seguimento dos pacientes com CMT. No entanto, estudos recentes têm indicado que níveis séricos elevados do antígeno carboidrato 19.9 (CA19.9), marcador tumoral bem estabelecido no em neoplasias pancreáticas, como um potencial marcador de agressividade e mortalidade em indivíduos com CMT avançado. O objetivo desse trabalho foi avaliar o papel do CA19.9 como marcador de agressividade tumoral em pacientes com CMT. Amostras tumorais de pacientes com CMT atendidos no Serviço de Endocrinologia do HCPA foram avaliados para expressão do CA19.9 por imunohistoquimica, através de anticorpo especifico. Para estudar a hipótese de os níveis de CA19.9 observados em pacientes com CMT estarem associados à desdiferenciação das células C, também avaliamos a expressão tecidual de CD133, um marcador para a identificação de células-tronco cancerígenas (CSC). A leitura das lâminas foi realizada por patologista, e quantificação da expressão foi inicialmente realizada pelo método de h-score. Adicionalmente as amostras foram classificadas de acordo com o padrão de expressão observado: células individuais, focos ou difuso. Setenta pacientes com CMT foram incluídos no estudo, 57,1% apresentavam a forma hereditária e 42,9% a forma esporádica. A idade média ao diagnóstico foi 36.1 (±16.3) anos e 58,6% foram do sexo feminino. A mediana dos níveis de calcitonina e CEA foram de 536pg/ml (49,35-1300,5) e 21,3ng/ml (3,6-52,6), respectivamente. Aproximadamente 53% dos pacientes apresentavam metástases locais e 20% à distância ao diagnóstico. Das 64 amostras de tumor primário disponíveis para analise, 56 (87,5%) apresentaram expressão do CA19.9, com mediana de h-score 14 (2-30). De forma semelhante, o CD133 estava expresso em 90.5% das amostras de tumor primário, no entanto não se observou nenhuma correlação entre os dois marcadores estudados (r=- 0.09; P=0.74). Não foram observadas diferenças na expressão de CA19.9 sobre idade, sexo, níveis 11 séricos calcitonina ou CEA (P>0,05). Curiosamente amostras de CMT hereditário tinham maior expressão de CA19.9 que amostras de CMT esporádico. Observamos três padrões de expressão distintos para o CA19.9: células individuais, focal e difuso. A maioria das amostras (64,3%) apresentaram o padrão de expressão focal. O padrão de células individuais foi observado em 17 (30,3%) das amostras e o padrão difuso em 3 (5,4%). As formas esporádica e hereditária da doença apresentaram diferentes padrões de expressão. De forma interessante, o CMT esporádico mostrouse associado ao padrão de células individuais (70,6%), enquanto a forma hereditária foi associada ao padrão focal de expressão (63,9%) (P=0,04). Adicionalmente, o padrão de células individuais foi associado a metástases local (P=0,055) enquanto que o padrão difuso, a metástases à distância (P=0,032). Nossos resultados demonstram expressão do CA19.9 na maioria das amostras de CMT. Diferenças nos níveis de expressão do CA19.9 não foram associadas às características clínicas ou oncológicas, sendo no entanto significativamente mais elevados em amostras de CMT hereditário. Três padrões de expressão distintos foram observados, sendo que o padrão difuso foi associado à presença de metástases à distância ao diagnóstico. Em conclusão, o CA19.9 é amplamente expresso no CMT e apresenta características distintas de outros marcadores atualmente utilizados. Estudos adicionais podem definir o papel desse marcador no manejo de pacientes de CMT. Medullary thyroid carcinoma (MTC) is a rare malignant tumor originating from parafollicular C-cell of the thyroid and corresponds to 4% of malignant neoplasms of this gland. MTC presents as a sporadic tumor (75-80%) or in hereditary form (20-25%). The only curative treatment currently available for MTC is surgical. However, this is only possible in cases of early diagnosis and the disease is restricted to the gland. In patients with advanced disease, where traditional therapeutic options such as chemotherapy and radiotherapy are not effective, tyrosine kinase inhibitors have demonstrated efficacy in disease-free survival. Levels of serum calcitonin, a specific biomarker for thyroid C-cells, and carcinoembryonic antigen (CEA) are widely used as markers in the diagnosis and follow-up of patients with MTC. However, recent studies have indicated that elevated serum levels of carbohydrate antigen 19.9 (CA19.9), a well established tumor marker in pancreatic neoplasms, are a potential marker of aggression and mortality in individuals with advanced MTC. The objective of this study was to evaluate the role of CA19.9 as a marker of tumor aggressiveness in patients with MTC. Tumor samples from MTC patients treated at the HCPA Endocrinology Service were evaluated for expression of CA19.9 by immunohistochemistry using a specific antibody. To study the hypothesis that CA19.9 levels observed in patients with MTC are associated with C-cell dedifferentiation, we also assessed the tissue expression of CD133, a marker for the identification of cancer stem cells (CSC). The reading of the slides was performed by a pathologist, and quantification of the expression was initially performed by the h-score method. Additionally, the samples were classified according to the observed expression pattern: individual cells, focal or diffuse. Seventy patients with MTC were included in the study, 57.1% presented the hereditary form and 42.9% presented sporadic form. The mean age at diagnosis was 36.1 (± 16.3) years and 58.6% were female. The median levels of calcitonin and CEA were 536pg/ml (49.35-1300.5) and 21.3ng/ml (3.6-52.6), respectively. Approximately 53% of the patients had local metastases and 20% at a distance at diagnosis. Of the 64 primary tumor samples available for analysis, 56 (87.5%) presented CA19.9 expression, with median h-score 14 (2-30). Similarly, CD133 was expressed in 90.5% of the primary tumor samples. However, no correlation was observed between the two markers studied (r=-0.09; P=0.74). No differences in CA19.9 expression were observed on age, sex, serum calcitonin or CEA levels (P>0.05). Curiously, samples of hereditary MTC had higher CA19.9 expression than sporadic MTC samples. We observed three distinct expression patterns for 13 CA19.9: individual cells, focal and diffuse. Most of the samples (64.3%) had the focal expression pattern. The individual cell pattern was observed in 17 (30.3%) of the samples and the diffuse pattern in 3 (5.4%). The sporadic and hereditary forms of the disease presented different patterns of expression. Interestingly, sporadic CMT was associated with the individual cell pattern (70.6%), while the hereditary form was associated with the focal expression pattern (63.9%) (P=0.04). In addition, the individual cell pattern was associated with local metastases (P=0.055) while the diffuse pattern, with distant metastases (P=0.032). Our results demonstrate expression of CA19.9 in the majority of MTC samples. Differences in CA19.9 expression levels were not associated with clinical or oncological features disease but it were significantly higher in hereditary MTC samples. Three distinct expression patterns were observed, and the diffuse pattern was associated with the presence of distant metastases at diagnosis. In conclusion, CA19.9 is widely expressed in MTC and presents distinct characteristics of other markers currently used. Additional studies may define the role of this marker in the management of MTC patients.

Objective: RET single nucleotide polymorphisms (SNPs) have been implicated in the pathogenesis and progression of medullary thyroid carcinoma (MTC). Here, we investigated the influence of multiple RET variants (G691S, L769L, S836S, and S904S) on the risk of MTC and tumor behavior. Design and methods: One hundred and seven MTC patients and 308 cancer-unaffected control individuals were included. SNPs were analyzed using Custom TaqMan Genotyping Assays. Haplotypes based on the combination of allelic variants were inferred using a Bayesian statistical method. Results: The minor allele frequencies in MTC patients were as follows: L769L: 28.0%, S836S: 8.9%, and G691S/S904S: 22.2%. The RET L769L and S836S SNPs were associated with increased risk of MTC (odds ratio (OR)Z1.95, 95% CI: 1.2–3.1, PZ0.005 and ORZ2.29, 95% CI: 1.2–4.5, PZ0.017 respectively). The adjusted OR for individuals harboring haplotypes with three or more polymorphic alleles was 3.79 (95% CI: 1.5–9.5; PZ0.004), indicating an additive effect of these variants on the risk for MTC. Among MTC patients, no significant associations were observed between RET variants and age of diagnosis or tumor size but serum calcitonin levels increased according to the number of risk alleles (PZ0.003). Remarkably, patients carrying haplotypes with three or four risk alleles had increased risk for lymph node and distant metastases at diagnosis (ORZ5.84, 95% CI: 1.1–31.2, PZ0.039). Further analysis using Kaplan–Meier model demonstrated that metastatic disease occurred earlier in individuals harboring multiple risk alleles. Conclusion: Our results demonstrated an additive effect of RET polymorphic alleles on the estimated risk of developing aggressive MTC.

Medullary thyroid carcinoma is a rare malignant tumor originating in parafollicular C cells. It accounts for 5 to 8% of all thyroid cancers. MTC develops in either sporadic (75%) or hereditary form (25%). Genetic and molecular studies have demonstrated the involvement of the RET proto-oncogene in hereditary MTC and, less often, in its sporadic form. Although a strong genotype-phenotype correlation has been described, wide clinical heterogeneity is observed among families with the same RET mutation or even in carriers of the same kindred. In recent years, several single nucleotide polymorphisms of the RET gene have been described in the general population as well as in patients with MTC. Some studies have reported associations between the presence of polymorphisms and development or progression of MTC. Nonetheless, other studies failed to demonstrate any effect of the RET variants. Differences in the genetic background of distinct populations or methodological approaches have been suggested as potential reasons for the conflicting results. Here, we review current knowledge concerning the molecular pathogenesis of sporadic and hereditary MTC. In particular, we analyze the role of RET polymorphisms in the clinical presentation and prognosis of MTC based on the current literature., info:eu-repo/semantics/published

The RET S836S variant has been associated with early onset and increased risk for metastatic disease in medullary thyroid carcinoma (MTC). However, the mechanism by which this variant modulates MTC pathogenesis is still open to discuss. Of interest, strong linkage disequilibrium (LD) between RET S836S and 3'UTR variants has been reported in Hirschsprung's disease patients., info:eu-repo/semantics/published

Pheochromocytoma (PHEO), a rare catecholamine producing tumor arising from the chromaffin cells, may occurs sporadically (76%-80%) or as part of inherited syndromes (20%-24%). Angiogenesis is a fundamental step in tumor proliferation and vascular endothelial growth factor (VEGF-A) is the most well-characterized angiogenic factor. The role of angiogenic markers in PHEO is not fully understood; investigations were therefore made to evaluate the expression of VEGF-A and its receptors in PHEO and correlate to clinical parameters. Twenty-nine samples of PHEO were evaluated for VEGF-A, VEGF receptor-1 (VEGFR-1) VEGFR-2 expression and microvessel density (MVD) by immunohistochemistry. Clinical data were reviewed in medical records. The mean age of patients was 38±14 years, and 69% were woman. VEGF-A, VEGFR-1 and VEGFR-2 staining were detected in nearly all PHEO samples. No significant correlation was observed between VEGF-A, VEGFR-1, VEGFR-2 expression or MVD and age at diagnosis, tumor size or sporadic and hereditary PHEO. However, the levels of expression of these molecules were significantly higher in malignant PHEO samples (p=0.027, p=0.003 and p=0.026, respectively).VEGF-A and its receptors were shown to be up-regulated in malignant PHEO, suggesting that these molecules might be considered as therapeutic targets for unresectable or metastatic tumors., info:eu-repo/semantics/published

Background: RET polymorphisms have been involved in the clinical presentation and prognosis of multiple endocrine neoplasia type 2 (MEN2)-associated medullary thyroid carcinoma.ObjectiveTo investigate the effect of RET variants on the penetrance of pheochromocytoma (PHEO) in MEN2 patients. Methods: The RET variants L769L, S836S, and G691S/S904S were evaluated in a cohort of 153 MEN2 patients attending a tertiary teaching hospital. A comparison of RET variant frequencies between patients with and without PHEO was performed. Kaplan–Meier curves and Cox regression analysis were used to estimate the effect of RET variants on the age-dependent penetrance.ResultsA total of 48 (31.4%) patients presented with MEN2-associated PHEOs. The mean age at diagnosis was 35.5±13.4 years, 60.4% of patients were women, and 92.8% had RET mutations at codon 634. The frequencies of RET polymorphisms were as follows: 20.1% L769L, 4.75% S836S, and 17.3% S904S/G691S. We did not observe any association between the frequencies of L769L, S836S, or S904S/G691S variants and PHEO development (all P>0.05). However, individuals carrying two RET polymorphic alleles had an increased estimated risk of PHEO (2.63; 95% CI, 1.4–5.0; P=0.004) and were younger at diagnosis when compared with those with one or no polymorphism (29.6±6.3 and 39.3±14.4 years respectively; P=0.006). Accordingly, additional analysis using Cox proportional hazard models demonstrated that the presence of two RET variants was associated with an increased risk for early PHEO development (hazard ratio, 5.99 (95% CI, 2.24–16.03); PConclusionsRET polymorphic alleles have an additive effect on the estimated risk of age-related PHEO penetrance in MEN2 patients.

Medullary thyroid carcinoma (MTC) is a rare malignant tumor originating from thyroid parafollicular C cells. This tumor accounts for 3%-4% of thyroid gland neoplasias. MTC may occur sporadically or be inherited. Hereditary MTC appears as part of the multiple endocrine neoplasia syndrome type 2A or 2B, or familial medullary thyroid cancer. Germ-line mutations of the RET proto-oncogene cause hereditary forms of cancer, whereas somatic mutations can be present in sporadic forms of the disease. The RET gene encodes a receptor tyrosine kinase involved in the activation of intracellular signaling pathways leading to proliferation, growth, differentiation, migration, and survival. Nowadays, early diagnosis of MTC followed by total thyroidectomy offers the only possibility of cure. Based on the knowledge of the pathogenic mechanisms of MTC, new drugs have been developed in an attempt to control metastatic disease. Of these, small-molecule tyrosine kinase inhibitors represent one of the most promising agents for MTC treatment, and clinical trials have shown encouraging results. Hopefully, the cumulative knowledge about the targets of action of these drugs and about the tyrosine kinase inhibitor-associated side effects will help in choosing the best therapeutic approach to enhance their benefits.

Medullary thyroid carcinoma (MTC) is a rare malignant tumor originating from thyroid parafollicular C cells. This tumor accounts for 3%–4% of thyroid gland neoplasias. MTC may occur sporadically or be inherited. Hereditary MTC appears as part of the multiple endocrine neoplasia syndrome type 2A or 2B, or familial medullary thyroid cancer. Germ-line mutations of the RET proto-oncogene cause hereditary forms of cancer, whereas somatic mutations can be present in sporadic forms of the disease. The RET gene encodes a receptor tyrosine kinase involved in the activation of intracellular signaling pathways leading to proliferation, growth, differentiation, migration, and survival. Nowadays, early diagnosis of MTC followed by total thyroidectomy offers the only possibility of cure. Based on the knowledge of the pathogenic mechanisms of MTC, new drugs have been developed in an attempt to control metastatic disease. Of these, small-molecule tyrosine kinase inhibitors represent one of the most promising agents for MTC treatment, and clinical trials have shown encouraging results. Hopefully, the cumulative knowledge about the targets of action of these drugs and about the tyrosine kinase inhibitor-associated side effects will help in choosing the best therapeutic approach to enhance their benefits.

Medullary thyroid carcinoma (MTC) is a rare malignant tumor originating from thyroid parafollicular C cells. This tumor accounts for 3-4% of thyroid gland neoplasias. MTC may occur sporadically or inherited. The hereditary MTC is part of syndromes of multiple endocrine neoplasia (MEN) 2A and 2B, familial medullary thyroid carcinoma (FMTC). Germline mutations of the RET (REarranged during Transfection) protooncogene cause hereditary form of cancer, whereas somatic mutations can be present in sporadic form of the disease. The RET gene encodes a receptor tyrosine kinase involved in the activation of intracellular signaling pathways leading to proliferation, growth, differentiation, migration and survival. Nowadays, the only possibility of cure for MTC patients consists of total thyroidectomy associated with lymph node dissection. Based on the knowledge of the pathogenic mechanisms of MTC, new drugs have been developed in attempt to control metastatic disease. Of these, the small-molecule tyrosine kinase inhibitors (TKIs) represent one of the most promising agents for MTC treatment and clinical trials have shown encouraging results. Hopefully, the cumulative knowledge about the targets of action of these drugs as well as TKI-associated side effects will help on choosing the best therapeutic approach in order to enhance its benefits.

Thyroid carcinoma is the most common malignant endocrine neoplasia. Differentiated thyroid carcinomas (DTCs) represent more than 90% of all thyroid carcinomas and comprise the papillary and follicular thyroid carcinoma subtypes. Anaplastic thyroid carcinomas correspond to less than 1% of all thyroid tumors and can arise de novo or by dedifferentiation of a differentiated tumor. The etiology of DTCs is not fully understood. Several genetic events have been implicated in thyroid tumorigenesis. Point mutations in the BRAF or RAS genes or rearranged in transformation (RET)/papillary thyroid carcinoma (PTC) gene rearrangements are observed in approximately 70% of papillary cancer cases. Follicular carcinomas commonly harbor RAS mutations and paired box gene 8 (PAX8)-peroxisome proliferator-activated receptor γ (PPARγ) rearrangements. Anaplastic carcinomas may have a wide set of genetic alterations, that include gene effectors in the mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K) and/or β-catenin signaling pathways. These distinct genetic alterations constitutively activate the MAPK, PI3K and β-catenin signaling pathways, which have been implicated in thyroid cancer development and progression. In this context, the evaluation of specific genes, as well as the knowledge of their effects on thyroid carcinogenesis may provide important information on disease presentation, prognosis and therapy, through the development of specific tyrosine kinase targets. In this review, we aimed to present an updated and comprehensive review of the recent advances in the understanding of the genetic basis of follicular cell-derived thyroid carcinomas, as well as the molecular mechanisms involved in tumor development and progression.