Tumores testiculares germinativos não-seminomas: imunoexpressão protéica de EGFR, Her2 E c-Kit
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2017-08-25
Autores
Quevedo, Francisco Carlos [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
As neoplasias testiculares constituem aproximadamente 1% dos cânceres masculinos. Dentre eles, os tumores que têm origem nas células germinativas (TTCG) são os mais frequentes. Por sua natureza, esses tumores têm padrão morfológico variado, sendo distribuídos em dois subgrupos: os seminomas e os não-seminomas. Esses últimos, por sua vez, são classificados em carcinomas embrionários, tumores do seio endodérmico, coriocarcinomas, teratomas e tumores mistos de células germinativas. Há consenso na literatura de que a invasão vascular verificada histologicamente no tumor primário é o melhor indicador preditivo de progressão da doença e recidiva. Estudos recentes demonstram o papel dos fatores de crescimento e seus receptores para avaliação prognóstica dos TTCG, no que o uso da imuno-histoquímica é fundamental. O presente estudo procurou avaliar pela técnica imuno-histoquímica à ocorrência da expressão do receptor do fator de crescimento epidérmico (EGFR), do Her2 e do c-Kit em uma série de TTCG não-seminomas primários de testículo. Além disso, explorou a possível relação entre a expressão desses marcadores com a evolução dos pacientes após terapêutica convencional. A série foi constituída de amostras parafinadas existentes no Laboratório de Anatomia Patológica e Citologia do Hospital Amaral Carvalho de Jaú, totalizando 103 pacientes que receberam o diagnóstico de tumor testicular de células germinativas não-seminomas (TTCGNS) no período 1996-2010. Dentre os 103 casos, predominaram os TTCGMNS (57,3%). Nestes, observou-se o predomínio de marcação para EGFR e c-Kit. O EGFR foi expresso quando o componente coriocarcinoma era predominante e o c-Kit no componente epitelial do teratoma. A hipótese do estudo, que os casos positivos para os marcadores analisados estariam correlacionados com sobrevida menor, não foi confirmada pela analise estatística de Kaplan-Meier; seria necessário um maior número de casos para se chegar a uma conclusão quanto à sobrevida. Superexpressão, amplificação gênica e mutações ativadoras são frequentes em tumores testiculares germinativos; deste modo, o uso da técnica de Hibridização Fluorescente in situ (FISH) foi utilizada para avaliação dos eventos gênicos relativos a imunoexpressão proteica, observada pelos resultados encontrados no estudo imuno-histoquímico. Somente um caso, classificado como TTCGM, apresentava amplificação para gene EGFR. Este caso apresentou bom prognóstico. Considerou-se que, a ausência de amplificação observada na maioria dos casos, deve-se a qualidade inadequada do material parafinado e estocado. Conclui-se que, na série estudada, os TTCGNS expressam os marcadores EGFR, Her2 e c-Kit, a depender do subtipo histológico; entretanto, estas proteínas não tiveram impacto prognostico. A amplificação gênica para o EGFR pode ocorrer de forma isolada, porem devido a condições técnicas restritivas, não foi possível observa-la nos demais casos positivos para EGFR pela técnica de imuno-histoquímico.
Testicular neoplasms constitute approximately 1% of male cancers. Among these, germ cell tumors (TGCT) are the most prevalent. These tumors show varied morphological patterns and are distributed into two subgroups: seminomas and non-seminomas. The latter, in turn, are classified as embryonal carcinomas, endodermal sinus tumors, choriocarcinomas, teratomas and mixed germ cell tumors. The consensus in the literature is that histological verification of vascular invasion (VI) in the primary tumor is the best predictor of disease progression and recurrence. However, recent studies have highlighted the role of growth factors and their receptors for prognostic evaluation of TGCT, in which the use of immunohistochemistry is fundamental. This study sought to evaluate the occurrence of epidermal growth factor receptor (EGFR), Her2 and c-Kit in a series of primary non-seminoma TGCTs. In addition, possible relationships between the expression of these markers and patient evolution following conventional therapy was investigated. The series consisted of paraffin-embedded samples from the Laboratory of Anatomical Pathology and Cytology of Amaral Carvalho Hospital in Jaú, SP, Brazil, of 103 patients diagnosed with testicular non-seminoma germ cell tumor (NSGCT) over a 15-year period (1996-2010). Among the 103 cases, testicular NSGCT predominated (57.3%), and among these, staining for EGFR and c-Kit predominated. EGFR was expressed when the choriocarcinoma component was predominant, and c-Kit when the epithelial component of the teratoma was predominant. The initial hypothesis that positive cases for any marker would be correlated to lower survival was not confirmed by Kaplan-Meier survival probability studies. A larger number of cases is required to reach any conclusions concerning survival. Gene overexpression and amplification and activating mutations are common in testicular germinal tumors, thus fluorescent in situ hybridization (FISH) was used to validate the genic events results obtained in the immunohistochemical study. Only one case, classified as mixed TGCT, showed EGFR gene amplification, and this case presented good prognosis. The lack of amplification observed in most cases was due to the inadequate quality of the stored, paraffinembedded materials. In conclusion, in the series studied, testicular NSGCT expressed EGFR, Her2 and c-Kit markers depending on the histological subtype; however, these proteins had no prognostic impact. Gene amplification for EGFR may occur in isolation, but due to the limited technical conditions, it was not observed in the other cases positive for EGFR using immunohistochemistry.
Testicular neoplasms constitute approximately 1% of male cancers. Among these, germ cell tumors (TGCT) are the most prevalent. These tumors show varied morphological patterns and are distributed into two subgroups: seminomas and non-seminomas. The latter, in turn, are classified as embryonal carcinomas, endodermal sinus tumors, choriocarcinomas, teratomas and mixed germ cell tumors. The consensus in the literature is that histological verification of vascular invasion (VI) in the primary tumor is the best predictor of disease progression and recurrence. However, recent studies have highlighted the role of growth factors and their receptors for prognostic evaluation of TGCT, in which the use of immunohistochemistry is fundamental. This study sought to evaluate the occurrence of epidermal growth factor receptor (EGFR), Her2 and c-Kit in a series of primary non-seminoma TGCTs. In addition, possible relationships between the expression of these markers and patient evolution following conventional therapy was investigated. The series consisted of paraffin-embedded samples from the Laboratory of Anatomical Pathology and Cytology of Amaral Carvalho Hospital in Jaú, SP, Brazil, of 103 patients diagnosed with testicular non-seminoma germ cell tumor (NSGCT) over a 15-year period (1996-2010). Among the 103 cases, testicular NSGCT predominated (57.3%), and among these, staining for EGFR and c-Kit predominated. EGFR was expressed when the choriocarcinoma component was predominant, and c-Kit when the epithelial component of the teratoma was predominant. The initial hypothesis that positive cases for any marker would be correlated to lower survival was not confirmed by Kaplan-Meier survival probability studies. A larger number of cases is required to reach any conclusions concerning survival. Gene overexpression and amplification and activating mutations are common in testicular germinal tumors, thus fluorescent in situ hybridization (FISH) was used to validate the genic events results obtained in the immunohistochemical study. Only one case, classified as mixed TGCT, showed EGFR gene amplification, and this case presented good prognosis. The lack of amplification observed in most cases was due to the inadequate quality of the stored, paraffinembedded materials. In conclusion, in the series studied, testicular NSGCT expressed EGFR, Her2 and c-Kit markers depending on the histological subtype; however, these proteins had no prognostic impact. Gene amplification for EGFR may occur in isolation, but due to the limited technical conditions, it was not observed in the other cases positive for EGFR using immunohistochemistry.
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Palavras-chave
Germinativos, Não-seminomas, Tumores testiculares, Germ cell, Non-seminoma, Testicular tumors