Thyroid carcinoma is the most common endocrine malignant neoplasia. Differentiated thyroid carcinomas (DTC), represent more than 90% of all thyroid carcinomas and comprise the papillary (PTC) and follicular thyroid carcinomas (FTC) subtypes. Anaplastic thyroid carcinoma (ATC) corresponds to less than 5% of all thyroid tumors. The etiology of DTC is not fully understood. Several genetic events have been implicated on differentiated thyroid tumorigenesis. Point mutations in BRAF and RAS genes and RET/PTC rearrangements are observed in about 70% of PTC cases. Follicular carcinomas commonly harbor RAS mutations and PAX8-PPARJ rearrangements. Anaplastic carcinomas may harbor a wide set of genetic alterations, as in genes encoding effectors in the mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinases (PI3K) and G-Catenin signaling pathways. These distinct genetic alterations are able to activate constitutively several signaling pathways as MAPK, PI3K and G-Catenin, which have been implicated on thyroid cancer development and progression. In this context, the evaluation of the specific oncogenes, as well as the knowledge of their effects on thyroid carcinomas can provide important information about the disease presentation, prognosis and therapy, through the development of specific tyrosine kinase targets. Particularly in this review, we explore the main genetic alterations observed in follicular cell-derived thyroid carcinomas as well as the molecular mechanisms involved in thyroid tumors development and progression.

Thyroid carcinoma is the most common endocrine malignant neoplasia. Differentiated thyroid carcinomas (DTC), represent more than 90% of all thyroid carcinomas and comprise the papillary (PTC) and follicular thyroid carcinomas (FTC) subtypes. Anaplastic thyroid carcinoma (ATC) corresponds to less than 5% of all thyroid tumors. The etiology of DTC is not fully understood. Several genetic events have been implicated on differentiated thyroid tumorigenesis. Point mutations in BRAF and RAS genes and RET/PTC rearrangements are observed in about 70% of PTC cases. Follicular carcinomas commonly harbor RAS mutations and PAX8-PPARJ rearrangements. Anaplastic carcinomas may harbor a wide set of genetic alterations, as in genes encoding effectors in the mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinases (PI3K) and G-Catenin signaling pathways. These distinct genetic alterations are able to activate constitutively several signaling pathways as MAPK, PI3K and G-Catenin, which have been implicated on thyroid cancer development and progression. In this context, the evaluation of the specific oncogenes, as well as the knowledge of their effects on thyroid carcinomas can provide important information about the disease presentation, prognosis and therapy, through the development of specific tyrosine kinase targets. Particularly in this review, we explore the main genetic alterations observed in follicular cell-derived thyroid carcinomas as well as the molecular mechanisms involved in thyroid tumors development and progression.

Thyroid carcinoma is the most common endocrine malignant neoplasia. Differentiated thyroid carcinomas (DTC), represent more than 90% of all thyroid carcinomas and comprise the papillary (PTC) and follicular thyroid carcinomas (FTC) subtypes. Anaplastic thyroid carcinoma (ATC) corresponds to less than 5% of all thyroid tumors. The etiology of DTC is not fully understood. Several genetic events have been implicated on differentiated thyroid tumorigenesis. Point mutations in BRAF and RAS genes and RET/PTC rearrangements are observed in about 70% of PTC cases. Follicular carcinomas commonly harbor RAS mutations and PAX8-PPARJ rearrangements. Anaplastic carcinomas may harbor a wide set of genetic alterations, as in genes encoding effectors in the mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinases (PI3K) and G-Catenin signaling pathways. These distinct genetic alterations are able to activate constitutively several signaling pathways as MAPK, PI3K and G-Catenin, which have been implicated on thyroid cancer development and progression. In this context, the evaluation of the specific oncogenes, as well as the knowledge of their effects on thyroid carcinomas can provide important information about the disease presentation, prognosis and therapy, through the development of specific tyrosine kinase targets. Particularly in this review, we explore the main genetic alterations observed in follicular cell-derived thyroid carcinomas as well as the molecular mechanisms involved in thyroid tumors development and progression.

Made available in DSpace on 2015-12-06T23:47:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2006 / BV UNIFESP: Teses e dissertações

Orientador: Laura Sterian Ward / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-13T00:19:00Z (GMT). No. of bitstreams: 1 Silva_JoycedoRosarioda_D.pdf: 4211439 bytes, checksum: d230e48c7d6fd16a7f9c75667ad83f9a (MD5) Previous issue date: 2009 / Resumo: A maior expressão de MUC1 tem sido relacionada com o pior prognóstico de diversas malignidades como o câncer de mama e pâncreas. Aproximadamente 20% dos carcinomas diferenciados da tiróide (CDT) evoluem com recidivas locais e a distância. O nosso objetivo foi o de avaliar o gene da MUC1 nos pacientes com CDT e relacionar com aspectos clínicos e anatomo-patológicos. CASUÍSTICA E MÉTODOS: Selecionamos 150 pacientes portadores de carcinoma papilífero (CP), 57 oriundos do Hospital das Clínicas da UNICAMP, acompanhados por 67 (73,29±39,83) meses, de 1995 a 2008 e 93 pacientes do Hospital AC Camargo - Fundação Antônio Prudente em São Paulo acompanhados por 41,37 (32,5±34,30) meses, de 1998 a 2008. Realizamos análise da expressão do gene da MUC 1 por imunoistoquímica e por PCR em Tempo Real e comparamos com dados de evolução clínica e do anatomopatológico. RESULTADOS: Observamos a expressão da proteína MUC1 em 82,19% dos pacientes com CP, no entanto, sem diferenças estatísticas para os dados de evolução clínica e do anatomo-patológico. A análise do RNA-m de MUC1 se correlacionou com a menor expressão nos indivíduos que apresentaram metástases ao diagnóstico (p valor=0,0216). Observamos a pior evolução: no sexo masculino, quando havia metástases ao diagnóstico, na ausência de tiroidite e nos tumores maiores que 4 cm. A presença de invasão tumoral foi mais freqüente nos indivíduos com ausência de tiroidite em 47% dos casos (p=0,0132; OR 2,473 - 95%IC: 1,198-5,104). CONCLUSÃO: Não conseguimos correlacionar a análise do gene MUC1 com aspectos clínicos e anatomo-patológicos de pior prognóstico para o CDT. / Abstract: The over expression of MUC1 has been related with the worst prognosis in malignancies like breast and pancreas cancer. We know that around 20% of the patients with differentiated thyroid cancer (DTC) can develop local and/or distant recurrences and because of that we decide to analyze the MUC1 gene in patients with DTC and tried to relate it with clinical and pathological patterns of the thyroid cancer. PATIENTS AND METHODS: We selected 150 patients with Papillary Thyroid Cancer: 57 from the Clinical Hospital of Campinas State University, followed up for 67 (73,29±39,83) months, since 1995 to 2008 and 93 patients from the A. C. Camargo Hospital - Antonio Prudente Foundation - São Paulo for 41,37 (32,5±34,3) months since 1998 to 2008. We analyzed the MUC1 gene with the immunohistochemistry and the Real Time - PCR techniques and compared the results with clinical and pathological data. RESULTS: The MUC1 expression was positive in 82,19% of the patients with papillary thyroid cancer, however, when we compared with clinical and pathological data, there was not statistical significance. The MUC1 m-RNA analysis was correlated with the less expression of the gene in the individuals who had had metastases at the diagnosis. We could observe the worst outcome in the individuals of the male gender, in the presence of metastases at the diagnosis, in the absence of thyroiditis in the non-neoplasic tissue and in tumors larger than 4 cm. The presence of tumoral invasion was significant in the patients with metastases to the diagnosis and in the ones without thyroiditis in 47% (p=0,0132; OR 2,473 - 95% CI: 1,198-5,104). CONCLUSION: We conclude that MUC1gene analysis was not useful to determine aggressive tumors nor to predict prognosis in papillary thyroid carcinomas. / Doutorado / Clinica Medica / Doutor em Clínica Médica