Relación entre la presencia de tiroiditis linfocítica con la gravedad y recurrencia/persistencia del carcinoma diferenciado de tiroides.

Introducción: Para el sistema endocrino la neoplasia más frecuente es el cáncer diferenciado de tiroides, con un claro incremento en su incidencia. Es importante encontrar asociaciones que posteriormente permitan establecer factores de riesgo y/o protectores claves en la estrategia terapéutica futura. Por lo que se investigó la relación entre la presencia de tiroiditis linfocítica con la gravedad y persistencia/recurrencia del carcinoma diferenciado de tiroides Materiales y métodos: se hizo un estudio de casos y controles de pacientes con carcinoma diferenciado de tiroides llevados a cirugía entre enero de 1997 y diciembre de 2012 en la Fundación Cardioinfantil, Bogotá, Colombia. Se evaluó la asociación entre la presencia de factores histopatológicos y la presencia de persistencia/recurrencia usando pruebas chi cuadrado y el OR. Para evaluar la presencia de asociación a nivel multivariado se utilizaron modelos de regresión binaria con enlace log log complementario. Resultados: la tiroiditis linfocítica no se asocia con la presencia de ninguna variable de severidad histopatológica. Sin embargo, la tiroiditis linfocítica se asoció con persistencia/recurrencia en presencia invasión vascular (OR 6.6 IC95% 1.4-32), invasión linfática (OR 5.4 IC95% 1.3-22.1), invasión de tejido peritiroideo (OR 1.0-12.3), vaciamiento central positivo (OR 5.1 IC 95% 1.0-2.6) y el, vaciamiento lateral positivo (OR 11.5 IC95% 1.0-12). Con un OR inclusive mayor respecto del grupo sin tiroiditis linfocítica en presencia de invasión linfática (OR 5.4 IC95% 1.3-22 vs 2.6 IC95% 1.2-5.6) y compromiso ganglionar en el vaciamiento lateral (OR 58 IC95% 7.1-476) independiente de la edad y el sexo. Conclusión: la tiroiditis linfocítica no se relaciona con marcadores de severidad histopatológica pero sí con mayor persistencia/recurrencia de la enfermedad.

Effects of let-7 microRNA on Cell Growth and Differentiation of Papillary Thyroid Cancer

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy and RET/PTC rearrangements represent key genetic events frequently associated to this cancer, enhancing proliferation and dedifferentiation by activation of the RET/PTC-RAS-BRAF-mitogen-activated protein kinase (MAPK) pathway. Recently, let-7 microRNA was found to reduce RAS levels in lung cancer, acting as a tumor suppressor gene. Here, we report that RET/PTC3 oncogenic activation in PCCL3 rat thyroid cells markedly reduces let-7f expression. Moreover, stable transfection of let-7 microRNA in TPC-1 cells, which harbor RET/PTC1 rearrangement, inhibits MAPK activation. As a result, let-7f was capable of reducing TPC-1 cell growth, and this might be explained, at least in part, by decreased messenger RNA (mRNA) expression of cell cycle stimulators such as MYC and CCND1 (cyclin D1) and increased P21 cell cycle inhibitor mRNA. In addition, let-7 enhanced transcriptional expression of molecular markers of thyroid differentiation such as TITF1 and TG. Thus, reduced expression of let-7f might be an essential molecular event in RET/PTC malignant transformation. Moreover, let-7f effects on thyroid growth and differentiation might attenuate neoplastic process of RET/PTC papillary thyroid oncogenesis through impairment of MAPK signaling pathway activation. This is the first functional demonstration of an association of let-7 with thyroid cancer cell growth and differentiation.

Tamoxifen inhibits transforming growth factor-alpha gene expression in human breast carcinoma samples treated with triiodothyronine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fipronil (active ingredient of acaricide frontline (R)) acting on the mice thyroid

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tamoxifen inhibits transforming growth factor-α gene expression in human breast carcinoma samples treated with triiodothyronine

Objectives: To examine the effects of triiodothyronine (T3), 17β-estradiol (E2), and tamoxifen (TAM) on transforming growth factor (TGF)-α gene expression in primary breast cancer cell cultures and interactions between the different treatments. Methods and results: Patients included in the study (no.=12) had been newly diagnosed with breast cancer. Fresh human breast carcinoma tissue was cut into 0.3-mm slices. These slices were placed in six 35-mm dishes on 2-ml organ culture medium. Dishes received the following treatments: dish 1: ethanol; dish 2: T3; dish 3: T3+TAM; dish 4: TAM; dish 5: E2; dish 6: E2+TAM. TGF-α mRNA content was normalized to glyceraldehyde-3-phosphate dehydrogenase mRNA levels. All tissues included in this study were positive for estrogen receptor (ER) and thyroid hormone receptor expression. Treatment with T3 for 48 h significantly increased TGF-α mRNA levels compared to controls (15-fold), and concomitant treatment with TAM reduced expression to 3.4-fold compared to controls. When only TAM was added to the culture medium, TGF-α mRNA expression increased 5.3-fold, significantly higher than with all other treatment modalities. Conclusion: We demonstrate that TGF-α mRNA expression is more efficiently upregulated by T3 than E2. Concomitant treatment with TAM had a mitigating effect on the T3 effect, while E2 induced TGF-α upregulation. Our findings show some similarities between primary culture and breast cancer cell lines, but also some important differences: a) induction of TGF-α, a mitogenic protein, by TAM; b) a differential effect of TAM that may depend on relative expression of ER α and β; and c) supraphysiological doses of T3 may induce mitogenic signals in breast cancer tissue under conditions of low circulating E2. ©2008, Editrice Kurtis.

Estudo clínico e genético de uma família portadora de carcinoma medular de tireóide

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diagnóstico, tratamento e seguimento do carcinoma medular de tireoide: recomendações do Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise de metilação do gene FOXE1 em carcinoma de células escamosas em cães: padronização metodológica

It is believed that epigenetic mechanisms such as DNA methylation are important for the tumorigenesis and maintenance of the altered state of tumor cells. DNA methylation occurs by the addition of a methyl group to carbon 5 of cytosine, catalyzed by the enzyme DNA methyl-transferase, which can change the expression of a gene, including the tumor suppressor genes. In human squamous cell carcinoma, several features have shown the etiological role of genes in tumor development. Among them, FOXE1 gene (forkhead box E1 - thyroid transcription factor) is presented with an important role in susceptibility to disease. Similarly the FOXE1 methylation pattern could alter the expression of this gene in dogs and predisposed to tumor on. Therefore, this study aims to investigate in dogs, the validity of the strategy employed in humans to analyze the FOXE1 methylation status. DNA extraction from fresh frozen tumoral samples was performed by Wizard Genomic® DNA Purification Kit. The methylation status was determined by MSP-PCR (methylation-specific polymerase chain reaction), using 2.0 ng of DNA treated with sodium bisulphate. One hundred micrograms of bisulphite-modified DNA was amplified using primers specific for either methylated or unmethylated DNA (primers sequences are available at http://pathology2.jhu.edu/pancreas/primer.pdf). The analysis of fragments was loaded on to 7% polyacrylamide gels and silver nitrate staining. In this stage of technical approach, 60% were FOXE1 hypermethylated. In conclusion, it was observed that the standard technique for assessing the methylation pattern of gene FOXE1 in humans can be used for the same evaluation in dogs. The correlation of these molecular data with clinical and histopathological parameters may have diagnostic and prognostic value and still be used as a tumor marker for therapeutic decision and surgical approach

Does radioiodine therapy in patients with differentiated thyroid cancer increase the frequency of another malignant neoplasm?

Objectives. To compare the frequency of another primary malignancy in patients with differentiated thyroid carcinoma (DTC) who received radioiodine therapy or not ((131)I). Material and Methods. 168 cases of DTC patients were retrospectively evaluated as to the frequency of another neoplasia by comparing patients with and without it, taking into account clinical, laboratory, and therapeutic parameters. Results. Another primary malignancy occurred in 8.9% of patients. Of these, 53.3% showed the malignancy before (131)I and 46.7% after it. By comparing both groups, the age at the moment of diagnosis of another neoplasia was 46.1 ± 20.2 years for the group before (131)I therapy and of 69.4 ± 11.4 years for the group after it (P = 0.02). Of the 148 patients treated with (131)I, 4.7% developed another malignancy. The latter were older (61 ± 17 years) than those who did not show another cancer type (44.1 ± 14.2 years) (P < 0.05). Conclusion. The frequency of another neoplasia found after (131)I was similar to that found before (131)I.

Obstrução de vias lacrimais associada ao tratamento radioiodoterápico de carcinoma de tireoide

OBJETIVO: Descrever uma série de pacientes portadores de obstrução do sistema lacrimal associado à radioiodoterapia para tratamento de carcinoma de tireoide, revisar os dados clínicos e a resposta ao tratamento cirúrgico desta rara complicação. MÉTODOS: Foi realizada uma análise retrospectiva dos achados oftalmológicos de pacientes com histórico de carcinoma de tireoide previamente submetidos à tireoidectomia e à RIT que foram encaminhados para cirurgia de vias lacrimais. RESULTADOS: Dezessete pacientes com carcinoma de tireoide tratados com tireoidectomia e RIT apresentaram obstrução do ducto nasolacrimal sintomática após período médio de 13,2 meses do tratamento do câncer. Onze pacientes tiveram epífora bilateral, 8 com mucocele de saco lacrimal. A idade dos pacientes variou entre 30 e 80 anos, sendo 10 com idade menor ou igual a 49 anos. A dose cumulativa média de radioiodo administrada foi de 571 mCi (variação entre 200-1200 mCi). Sintomas de obstrução nasal e aumento de glândulas salivares ocorreram em 53% dos pacientes. Todos os pacientes foram submetidos à dacriocistorrinostomia. Observou-se ainda que nos 3 pacientes mais jovens houve maior sangramento intraoperatótio e dilatação de saco lacrimal. A resolução completa da epífora e da dacriocistite ocorreu em 82,4%, e foi parcial em 17,6% (3 pacientes mantiveram queixa unilateral após a correção da obstrução bilateralmente). O seguimento médio foi de 6 meses (intervalo: 2-24 meses). CONCLUSÕES: Alta dose cumulativa de radioiodo, disfunção nasal e de glândulas salivares estão associadas à obstrução das vias lacrimais. Observa-se uma maior porcentagem de pacientes mais jovens apresentando quadro de dacriocistite quando comparado à dacrioestenose idiopática. A absorção de iodo radioativo pela mucosa do ducto nasolacrimal com subsequente inflamação, edema e fibrose parece ter relação direta com a obstrução do ducto nasolacrimal. O conhecimento desta complicação é importante para o estudo e abordagem correta desses pacientes.

Iodide treatment acutely increases pendrin (SLC26A4) mRNA expression in the rat thyroid and the PCCl3 thyroid cell line by transcriptional mechanisms

Iodine is a critical element involved in thyroid hormone synthesis. Its efflux into the follicular lumen is thought to occur, in part, through pendrin at the apical membrane of thyrocytes. This study attempted to investigate whether iodide administration affects SLC26A4 mRNA expression in rat thyroid and in PCCl3 cells. Rats and cells were treated or not with Nal from 30 min up to 48 h. One group was concomitantly treated with sodium perchlorate. SLC26A4 mRNA expression was also investigated in PCCl3 cells treated with actinomycin D prior to Nal treatment. Iodide administration significantly increased SLC26A4 mRNA content in both models. The simultaneous administration of Nal and perchlorate, as well as the treatment of PCCl3 cells with actinomycin D prevented this effect, indicating that intracellular iodide is essential for this event, which appears to be triggered by transcriptional mechanisms. These data show that intracellular iodide rapidly upregulates SLC26A4 mRNA expression. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

Diagnostic utility of immunohistochemistry in distinguishing trichoepithelioma and basal cell carcinoma: evaluation using tissue microarray samples

Trichoepithelioma is a benign neoplasm that shares both clinical and histological features with basal cell carcinoma. It is important to distinguish these neoplasms because they require different clinical behavior and therapeutic planning. Many studies have addressed the use of immunohistochemistry to improve the differential diagnosis of these tumors. These studies present conflicting results when addressing the same markers, probably owing to the small number of basaloid tumors that comprised their studies, which generally did not exceed 50 cases. We built a tissue microarray with 162 trichoepithelioma and 328 basal cell carcinoma biopsies and tested a panel of immune markers composed of CD34, CD10, epithelial membrane antigen, Bcl-2, cytokeratins 15 and 20 and D2-40. The results were analyzed using multiple linear and logistic regression models. This analysis revealed a model that could differentiate trichoepithelioma from basal cell carcinoma in 36% of the cases. The panel of immunohistochemical markers required to differentiate between these tumors was composed of CD10, cytokeratin 15, cytokeratin 20 and D2-40. The results obtained in this work were generated from a large number of biopsies and resulted in the confirmation of overlapping epithelial and stromal immunohistochemical profiles from these basaloid tumors. The results also corroborate the point of view that trichoepithelioma and basal cell carcinoma tumors represent two different points in the differentiation of a single cell type. Despite the use of panels of immune markers, histopathological criteria associated with clinical data certainly remain the best guideline for the differential diagnosis of trichoepithelioma and basal cell carcinoma. Modern Pathology (2012) 25, 1345-1353; doi: 10.1038/modpathol.2012.96; published online 8 June 2012

Characterization of new molecular targets involved in iodide flux in the thyroid gland: the anoctamins

Iodide transport is necessary for the synthesis of thyroid hormones following accumulation in the follicular lumen out of thyroid cells, via channels unknown with the exception of pendrin. According to our hypothesis, TMEM16A could be the main molecular identity of the channel mediating iodide efflux in the thyroid gland. TMEM16A is the prior candidate for calcium-activated chloride conductance (CaCC). TMEM16A belongs to the TMEM16/anoctamin family comprising ten members (TMEM16A-K). Higher affinity of TMEM16A for iodide and predicted expression in the thyroid gland suggest its mediation of iodide efflux. The aim of this project was to identify the role of TMEM16A in iodide transport in the thyroid gland, by characterizing its molecular expression and functional properties. We demonstrated that TMEM16F, H, K transcripts are expressed in FRTL-5 thyroid cells, as well as TMEM16A, which is TSH-independent. Tumor tissue from human thyroid maintains TMEM16A expression. Functional in vivo experiments in FRTL-5, stably expressing YFP-H148Q/I152L fluorescent protein as a biosensor, showed that iodide efflux is stimulated by agonists of purinergic receptors with an order of potency of ATP>UTP>ADP (compatible with an involvement of P2Y purinergic receptors), and by agonists of adrenergic receptors (epinephrine, norepinephrine and phenylephrine). Iodide efflux was blocked by α-receptor antagonists prazosin and phentolamine, consistent with a role of α1 adrenergic receptors. Iodide efflux was specifically dependent on calcium mobilized from intracellular compartments and induced by the calcium ionophore ionomycin. CaCC blockers suppressed ionomycin-/ATP-/epinephrine-stimulated iodide efflux. Heterologous expression of TMEM16A in CHO K1 cells induced calcium-activated iodide fluxes. All these results support the hypothesis of the involvement of TMEM16A in calcium-dependent iodide efflux induced by receptor agonists in thyroid cells. TMEM16A may represent a new pharmacological target for thyroid cancer therapy, since its blockade may enhance the retention of radioiodide by tumour cells enhancing the efficacy of radioablative therapy.

High sensitivity analysis of BRAF mutations in neoplastic and non-neoplastic thyroid lesions

The clonal distribution of BRAFV600E in papillary thyroid carcinoma (PTC) has been recently debated. No information is currently available about precursor lesions of PTCs. My first aim was to establish whether the BRAFV600E mutation occurs as a subclonal event in PTCs. My second aim was to screen BRAF mutations in histologically benign tissue of cases with BRAFV600E or BRAFwt PTCs in order to identify putative precursor lesions of PTCs. Highly sensitive semi-quantitative methods were used: Allele Specific LNA quantitative PCR (ASLNAqPCR) and 454 Next-Generation Sequencing (NGS). For the first aim 155 consecutive formalin-fixed and paraffin-embedded (FFPE) specimens of PTCs were analyzed. The percentage of mutated cells obtained was normalized to the estimated number of neoplastic cells. Three groups of tumors were identified: a first had a percentage of BRAF mutated neoplastic cells > 80%; a second group showed a number of BRAF mutated neoplastic cells < 30%; a third group had a distribution of BRAFV600E between 30-80%. The large presence of BRAFV600E mutated neoplastic cell sub-populations suggests that BRAFV600E may be acquired early during tumorigenesis: therefore, BRAFV600E can be heterogeneously distributed in PTC. For the second aim, two groups were studied: one consisted of 20 cases with BRAFV600E mutated PTC, the other of 9 BRAFwt PTCs. Seventy-five and 23 histologically benign FFPE thyroid specimens were analyzed from the BRAFV600E mutated and BRAFwt PTC groups, respectively. The screening of BRAF mutations identified BRAFV600E in “atypical” cell foci from both groups of patients. “Unusual” BRAF substitutions were observed in histologically benign thyroid associated with BRAFV600E PTCs. These mutations were very uncommon in the group with BRAFwt PTCs and in BRAFV600E PTCs. Therefore, lesions carrying BRAF mutations may represent “abortive” attempts at cancer development: only BRAFV600E boosts neoplastic transformation to PTC. BRAFV600E mutated “atypical foci” may represent precursor lesions of BRAFV600E mutated PTCs.

Poorly differentiated thyroid carcinomas: how much poorly differentiated is needed?

Poorly differentiated (PD) carcinomas of the thyroid are conceptually situated between well-differentiated (papillary or follicular) carcinomas and anaplastic thyroid carcinomas. Although the morphologic criteria for PD tumors are well defined, it is not clear how much of a PD area besides a well-differentiated component in a given tumor is required to allow such a diagnosis.