Our purpose was to determine the effects on mammary gland development in prepubertal heifers given the anti-estrogen tamoxifen. Sixteen Holstein calves were randomly assigned to one of two treatment groups: tamoxifen-injected (TAM) or control (CON). Calves were subcutaneously injected daily from 28 to 120 days of age with 0.3 mg/kg tamoxifen or carrier. At 120 days calves were euthanized and udders removed. Weight of trimmed parenchymal tissue (left rear quarter) was dramatically lower in TAM calves than in CON calves (p < 0.0003; 16.1 vs. 34.8 g). Parenchymal samples from three regions of the left rear quarter (lower, middle and outer regions) were processed for immunohistochemical staining for Estrogen Receptor α and Progesterone Receptor, myoepithelial cells, and label retaining cells. Overall, the proportion of neither ER nor PR labeled cells was impacted by TAM treatment. However, imaging analysis indicated a markedly higher intensity of ER expression in CON calves. TAM caused an increase in myoepithelial cell differentiation similar to what is seen in ovariectomy. We were able to effectively use a new technique of multispectral imaging to identify label retaining cells, which led to the discovery of an increase in the percentage of label retaining cells in TAM compared to CON. While treatment with the anti-estrogen tamoxifen reduced mammary parenchymal mass similarly to OVX, the mechanism(s) involved appear to differ. This suggests that the impacts of ovariectomy are only partially explained by the absence of estrogen. / Master of Science

Changes in the microenvironment have been implicated in the transition of pre-invasive ductal carcinoma in-situ (DCIS) to invasive breast cancer. Normal myoepithelial cells have a tumour suppressor phenotype but they are altered in DCIS and ultimately lost with transition to invasive cancer. A consistent change in DCIS is up-regulation of the integrin αvβ6 in myoepithelial cells. Preliminary observations identified a correlation between myopeithelial αvβ6 and an increased peri-ductal inflammatory infiltrate. The hypothesis of this study is that the altered myoepithelial phenotype influences the peri-ductal inflammatory environment, which in turn mediates a pro-apoptotic effect on myoepithelial cells contributing to their loss. To investigate this, the inflammatory infiltrate was characterised in a series of DCIS tissue in relation to αvβ6 status. This demonstrated significantly higher levels of CD4+ve and FOXP3+ve T cells around αvβ6+ve DCIS ducts compared to αvβ6-ve ducts (P=<0.01), suggesting an increase in Treg cells. In-vivo, Matrigel plugs containing injected into the flanks of female C57/Blk6 normal mice generated influx of higher levels of CD4+ve cells (p=0.005) and FOXP3+ T cells (p=0.007) in the presence of αvβ6+ve myoepithelial cells compared to αvβ6-ve cells, supporting the findings in human tissue samples. Since Treg cells produce TRAIL that can induce apoptosis, we investigated the influence of αvβ6 on myoepithelial cells on the levels of TRAIL in T cells and the hypothesis that αvβ6-positive myoepithelial ells may be more susceptible to TRAIL-induced apoptosis, leading to loss of the myoepithelial barrier. Firstly, levels of TRAIL in Jurkat and primary T cell populations co-cultured with β4 (ii) or β6 myoepithelial cells were measured. This demonstrated a higher level of TRAIL in primary T cells co-cultured β6 myoepithelial cells compared to those co-cultured with β4 myoepithelial cells. β6+ve and β6-ve myoepithelial cells were exposed to TRAIL, and this demonstrated that TRAIL enhanced apoptosis, measured by cleaved PARP, in β6+ve cells. Furthermore, these cells showed loss of the anti-apoptotic protein Galectin-7, and knockdown of Galectin-7 in normal β6-ve myoepithelial cells rendered them more susceptible to TRAIL-induced apoptosis. In DCIS tissues, an inverse relationship between αvβ6 and Galectin-7 in myoepithelial cells was demonstrated, and Cytokine Array analysis showed that αvβ6+ve myoepithelial cells express higher levels of IL-16, which has a role in Treg cell recruitment. Taken together these results suggest that expression of αvβ6 by myoepithelial cells in DCIS generates a tumour-promoter peri-ductal inflammatory infiltrate through altered cytokine release, is associated with reduced galectin-7 expression and enhances myoepithelial cell apoptosis in response to TRAIL. This provides a potential mechanism by which myoepithelial cells may be lost during evolution of DCIS and so contribute to progression to invasive disease.

Os marcadores prognósticos em mastologia têm sido utilizados como apoio diagnóstico para prever o comportamento dos neoplasmas mamários (prognóstico) e determinar a provável resposta ao tratamento pré ou pós-cirúrgico. Estudos têm sido feitos sobre o prognóstico dos tumores mamários caninos (TMCs) que apresentam semelhanças e diferenças com tumores mamários humanos. Além disso, esses tumores exibem, com alta freqüência, proliferação de células mioepiteliais que podem sofrer metaplasia, acompanhada de alterações moleculares. O presente estudo teve o objetivo de verificar a expressão imuno-histoquímica e a associação de diferentes marcadores utilizados como prognósticos nos tumores de mama humana (RE, RP, c-erbB-2 e Ki-67) e marcadores mioepiteliais (p63, CK5 e vimentina) nos TMCs. O primeiro artigo analisa a expressão desses marcadores em 35 tumores encontrados em onze fêmeas caninas nas quais foram identificados tumores malignos múltiplos nas glândulas mamárias. Cada tipo histológico analisado em fêmeas portadoras de tumores múltiplos expressou marcadores prognósticos e mioepiteliais peculiares à sua histogênese, porém houve associação dessa expressão apenas em alguns tipos celulares presentes nos TMCs. Os tumores com componente epitelial carcinomatoso não apresentaram diferenças significativas, no entanto, nos tumores com componente complexo e misto, ocorreu associação entre a expressão da p63, CK5 e vimentina. No conjunto de marcadores estudados, a p63 e a CK5 mostram-se promissoras na elucidação da transformação das células mioepiteliais concomitante à invasão tumoral e com relação à expressão da vimentina que se mostrou bem evidenciada durante a transformação da célula mioepitelial proliferada a célula participante do mesênquima do neoplasma invasor em mamas de caninos, ao menos nos aspectos de expressão molecular e morfológica. O segundo artigo analisa os marcadores mioepiteliais em 82 casos de TMCs malignos. Este estudo comprovou a freqüência e a associação da expressão desses marcadores em determinados tipos histológicos tumorais e celulares, permitindo a identificação das células mioepiteliais em transformação na maior parte dos TMCs malignos, notadamente, os que apresentam componente mesenquimal metaplásico. Mais estudos devem ser feitos na tentativa de verificar a significância da expressão encontrada no comportamento biológico desses tumores. / Prognostic markers in mastology have been used as diagnostic support, to predict the behavior of mammary neoplasias (prognosis) and to determine their possible response to treatment before or after surgery. Studies have been conducted on the prognosis of canine mammary gland tumors (MGTs), which show similarities to and differences from human breast tumors. In addition, these tumors often show proliferation of myoepithelial cells, which may undergo metaplasia, accompanied by molecular alterations. The aim of the present study was to check the immunohistochemical expression and the association between different markers used as prognostic factors in human breast tumors (ER, RP, c-erbB-2 and Ki-67) and myoepithelial markers (p63, CK5 and vimentin) in MGTs. The first article analyzes the expression of these markers in 35 tumors in 11 female dogs, where multiple tumors were identified in the mammary glands. Each histological type analyzed in the female dogs with multiple tumors expressed prognostic and myoepithelial markers that were peculiar to their histogenesis, but the association of this expression was observed only in some cell types of MGTs. Tumors with a carcinomatous epithelial component did not have significant differences, but tumors with complex and mixed components showed association between the expressions of p63, CK5 and vimentin. Of the group of investigated markers, p63 and CK5 proved to be promising tools in elucidating the transformation of myoepithelial cells concomitantly to tumor invasion and in terms of vimentin expression, which was quite pronounced in this transformation from proliferating myoepithelial cells into cells that participate in the mesenchyma of the invasive neoplasia in canine mammary glands, at least with regard to the aspects of molecular and morphological expression. The second article analyzes myoepithelial markers in 82 cases of malignant MGTs. This study corroborated the frequency and association of the expression of these markers in certain histological tumor and cell types, allowing for the identification of myoepithelial cells in transformation in most malignant MGTs, chiefly those with a metaplastic mesenchymal component. Further studies are necessary in order to assess the importance of expression found in the biological behavior of these tumors.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The p63 protein is expressed in the nuclei of the mammary myoepithelial cells and has synergisms or antagonisms with p53 tumor suppressor protein. The immunohistochemistry expression of p63 was studied for access the role of myoepithelial cells in histogenesis of the mixed tumors. Additionally, the possible association between p63 and p53 for access the biological aspects of this tumors was evaluated. Four specimens of the normal gland, 20 benign mixed tumors, 35 carcinomas in mixed tumors and 11 tubulopapilary carcinomas were evaluated. Myoepithelial cells forming layers periductals/periacinars continuous were reactive for protein p63 in normal gland and in benign mixed tumor. The carcinomas in mixed tumors and 72.7% (8/11) tubulopapilary carcinomas were reactive for p63. In the mixed tumors star and spindle shaped cells were reactive for p63. The p53 protein was expressed in 20.0% (4/20), 28.6% (10/35) and 36.7% (4/11), benign mixed tumors, carcinoma in mixed tumors and tubulopapilary carcinomas, respectively. There was not relation between p63 and p53 expression in none type of tumor. The present study point the participation of the mioepithelial cells in the histogenesis of the mixed tumors. The decrease in p63 expression in the basal myoepithelial cells of the carcinomas may be important for tumoral progression. / A proteína p63 é expressa no núcleo das células mioepiteliais da mama e apresenta funções sinérgicas ou antagonistas com a proteína de supressão tumoral p53. A expressão imuno-histoquímica de p63 foi estudada para acessar o papel das células mioepiteliais na histogênese dos tumores mistos. Adicionalmente, avaliou-se a possível relação entre expressão imuno-histoquímica de p63 e p53 com a finalidade de obter informações sobre a biologia desses tumores. Quatro amostras de mama normais, 20 tumores mistos benignos, 35 carcinomas em tumores mistos e 11 carcinomas tubulopapilares foram avaliados. Células mioepiteliais, formando camadas periductais/periacinares contínuas, foram imunoreativas para p63 na mama normal e nos tumores mistos benignos. Todos os carcinomas em tumores mistos e 72,7% (8/11) dos carcinomas tubulopapilares foram reativos para p63. A reatividade para p63 foi superior nos tumores mistos benignos quando comparada com os carcinomas. Nos tumores mistos, células mioepiteliais com formato fusiforme e estrelado, presentes no estroma mucinoso também foram reativas para p63. A proteína p53 foi expressa em 20,0% (4/20), 28,6% (10/35) e 36,4% (4/11) dos tumores mistos benignos, carcinomas em tumores mistos e carcinomas tubulopapilares, respectivamente. Não houve relação entre a expressão de p53 e p63 nos diferentes tipos tumorais. O presente estudo evidenciou a participação das células mioepiteliais na histogênese dos tumores mistos. A diminuição da expressão de p63 nas células mioepiteliais que compõem a camada basal dos carcinomas pode ser um evento importante para a progressão tumoral.

Os marcadores prognósticos em mastologia têm sido utilizados como apoio diagnóstico para prever o comportamento dos neoplasmas mamários (prognóstico) e determinar a provável resposta ao tratamento pré ou pós-cirúrgico. Estudos têm sido feitos sobre o prognóstico dos tumores mamários caninos (TMCs) que apresentam semelhanças e diferenças com tumores mamários humanos. Além disso, esses tumores exibem, com alta freqüência, proliferação de células mioepiteliais que podem sofrer metaplasia, acompanhada de alterações moleculares. O presente estudo teve o objetivo de verificar a expressão imuno-histoquímica e a associação de diferentes marcadores utilizados como prognósticos nos tumores de mama humana (RE, RP, c-erbB-2 e Ki-67) e marcadores mioepiteliais (p63, CK5 e vimentina) nos TMCs. O primeiro artigo analisa a expressão desses marcadores em 35 tumores encontrados em onze fêmeas caninas nas quais foram identificados tumores malignos múltiplos nas glândulas mamárias. Cada tipo histológico analisado em fêmeas portadoras de tumores múltiplos expressou marcadores prognósticos e mioepiteliais peculiares à sua histogênese, porém houve associação dessa expressão apenas em alguns tipos celulares presentes nos TMCs. Os tumores com componente epitelial carcinomatoso não apresentaram diferenças significativas, no entanto, nos tumores com componente complexo e misto, ocorreu associação entre a expressão da p63, CK5 e vimentina. No conjunto de marcadores estudados, a p63 e a CK5 mostram-se promissoras na elucidação da transformação das células mioepiteliais concomitante à invasão tumoral e com relação à expressão da vimentina que se mostrou bem evidenciada durante a transformação da célula mioepitelial proliferada a célula participante do mesênquima do neoplasma invasor em mamas de caninos, ao menos nos aspectos de expressão molecular e morfológica. O segundo artigo analisa os marcadores mioepiteliais em 82 casos de TMCs malignos. Este estudo comprovou a freqüência e a associação da expressão desses marcadores em determinados tipos histológicos tumorais e celulares, permitindo a identificação das células mioepiteliais em transformação na maior parte dos TMCs malignos, notadamente, os que apresentam componente mesenquimal metaplásico. Mais estudos devem ser feitos na tentativa de verificar a significância da expressão encontrada no comportamento biológico desses tumores. / Prognostic markers in mastology have been used as diagnostic support, to predict the behavior of mammary neoplasias (prognosis) and to determine their possible response to treatment before or after surgery. Studies have been conducted on the prognosis of canine mammary gland tumors (MGTs), which show similarities to and differences from human breast tumors. In addition, these tumors often show proliferation of myoepithelial cells, which may undergo metaplasia, accompanied by molecular alterations. The aim of the present study was to check the immunohistochemical expression and the association between different markers used as prognostic factors in human breast tumors (ER, RP, c-erbB-2 and Ki-67) and myoepithelial markers (p63, CK5 and vimentin) in MGTs. The first article analyzes the expression of these markers in 35 tumors in 11 female dogs, where multiple tumors were identified in the mammary glands. Each histological type analyzed in the female dogs with multiple tumors expressed prognostic and myoepithelial markers that were peculiar to their histogenesis, but the association of this expression was observed only in some cell types of MGTs. Tumors with a carcinomatous epithelial component did not have significant differences, but tumors with complex and mixed components showed association between the expressions of p63, CK5 and vimentin. Of the group of investigated markers, p63 and CK5 proved to be promising tools in elucidating the transformation of myoepithelial cells concomitantly to tumor invasion and in terms of vimentin expression, which was quite pronounced in this transformation from proliferating myoepithelial cells into cells that participate in the mesenchyma of the invasive neoplasia in canine mammary glands, at least with regard to the aspects of molecular and morphological expression. The second article analyzes myoepithelial markers in 82 cases of malignant MGTs. This study corroborated the frequency and association of the expression of these markers in certain histological tumor and cell types, allowing for the identification of myoepithelial cells in transformation in most malignant MGTs, chiefly those with a metaplastic mesenchymal component. Further studies are necessary in order to assess the importance of expression found in the biological behavior of these tumors.

Os marcadores prognósticos em mastologia têm sido utilizados como apoio diagnóstico para prever o comportamento dos neoplasmas mamários (prognóstico) e determinar a provável resposta ao tratamento pré ou pós-cirúrgico. Estudos têm sido feitos sobre o prognóstico dos tumores mamários caninos (TMCs) que apresentam semelhanças e diferenças com tumores mamários humanos. Além disso, esses tumores exibem, com alta freqüência, proliferação de células mioepiteliais que podem sofrer metaplasia, acompanhada de alterações moleculares. O presente estudo teve o objetivo de verificar a expressão imuno-histoquímica e a associação de diferentes marcadores utilizados como prognósticos nos tumores de mama humana (RE, RP, c-erbB-2 e Ki-67) e marcadores mioepiteliais (p63, CK5 e vimentina) nos TMCs. O primeiro artigo analisa a expressão desses marcadores em 35 tumores encontrados em onze fêmeas caninas nas quais foram identificados tumores malignos múltiplos nas glândulas mamárias. Cada tipo histológico analisado em fêmeas portadoras de tumores múltiplos expressou marcadores prognósticos e mioepiteliais peculiares à sua histogênese, porém houve associação dessa expressão apenas em alguns tipos celulares presentes nos TMCs. Os tumores com componente epitelial carcinomatoso não apresentaram diferenças significativas, no entanto, nos tumores com componente complexo e misto, ocorreu associação entre a expressão da p63, CK5 e vimentina. No conjunto de marcadores estudados, a p63 e a CK5 mostram-se promissoras na elucidação da transformação das células mioepiteliais concomitante à invasão tumoral e com relação à expressão da vimentina que se mostrou bem evidenciada durante a transformação da célula mioepitelial proliferada a célula participante do mesênquima do neoplasma invasor em mamas de caninos, ao menos nos aspectos de expressão molecular e morfológica. O segundo artigo analisa os marcadores mioepiteliais em 82 casos de TMCs malignos. Este estudo comprovou a freqüência e a associação da expressão desses marcadores em determinados tipos histológicos tumorais e celulares, permitindo a identificação das células mioepiteliais em transformação na maior parte dos TMCs malignos, notadamente, os que apresentam componente mesenquimal metaplásico. Mais estudos devem ser feitos na tentativa de verificar a significância da expressão encontrada no comportamento biológico desses tumores. / Prognostic markers in mastology have been used as diagnostic support, to predict the behavior of mammary neoplasias (prognosis) and to determine their possible response to treatment before or after surgery. Studies have been conducted on the prognosis of canine mammary gland tumors (MGTs), which show similarities to and differences from human breast tumors. In addition, these tumors often show proliferation of myoepithelial cells, which may undergo metaplasia, accompanied by molecular alterations. The aim of the present study was to check the immunohistochemical expression and the association between different markers used as prognostic factors in human breast tumors (ER, RP, c-erbB-2 and Ki-67) and myoepithelial markers (p63, CK5 and vimentin) in MGTs. The first article analyzes the expression of these markers in 35 tumors in 11 female dogs, where multiple tumors were identified in the mammary glands. Each histological type analyzed in the female dogs with multiple tumors expressed prognostic and myoepithelial markers that were peculiar to their histogenesis, but the association of this expression was observed only in some cell types of MGTs. Tumors with a carcinomatous epithelial component did not have significant differences, but tumors with complex and mixed components showed association between the expressions of p63, CK5 and vimentin. Of the group of investigated markers, p63 and CK5 proved to be promising tools in elucidating the transformation of myoepithelial cells concomitantly to tumor invasion and in terms of vimentin expression, which was quite pronounced in this transformation from proliferating myoepithelial cells into cells that participate in the mesenchyma of the invasive neoplasia in canine mammary glands, at least with regard to the aspects of molecular and morphological expression. The second article analyzes myoepithelial markers in 82 cases of malignant MGTs. This study corroborated the frequency and association of the expression of these markers in certain histological tumor and cell types, allowing for the identification of myoepithelial cells in transformation in most malignant MGTs, chiefly those with a metaplastic mesenchymal component. Further studies are necessary in order to assess the importance of expression found in the biological behavior of these tumors.

Mammary cancer is a serious health issue in pet rabbits; prognostic factors are unknown. In a normal mammary gland, glandular secretory cells are surrounded by a single continuous layer of myoepithelial cells. In non-invasive mammary carcinomas, tumor cells are delineated by an intact myoepithelial layer, which is gradually lost to invasive carcinomas. The main aim of this study was to determine in rabbit mammary carcinomas (n = 119) the expression of myoepithelial markers that have prognostic significance in human cancer. Results show that all cases contained some retained myoepithelial cells. In 93% of the tumors, neoplastic cells expressed the myoepithelial marker calponin. There was a statistically significant association between higher percentages of calponin-containing cancer cells and histological features indicative of a better tumor differentiation, i.e., a lower proliferation of tumor cells, an increased percentage of tubular growth within the tumor, and a lower tumor grade, respectively. These results suggest that rabbit mammary carcinomas develop from progression of non-invasive cancer forms, and that calponin expression in cancer cells likely represents a favorable prognostic factor. The latter hypothesis has to be confirmed in long-term follow-up studies.

Orientador: Jose Vassalo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-07T05:09:42Z (GMT). No. of bitstreams: 1 Schenka_NataliaGuimaraesdeMoraes_D.pdf: 3809756 bytes, checksum: d4d7db8aeacfcd3c285cdee5b7c0a182 (MD5) Previous issue date: 2006 / Resumo: O sistema ductal da mama é revestido por duas camadas de células: uma constituída de células epiteliais luminais e outra de células mioepiteliais (CME). A identificação das CMEs é de grande importância na rotina em patologia cirúrgica, já que estas estão presentes em lesões benignas e geralmente ausentes nas malignas. Contudo, esta identificação morfológica (i.e., à hematoxilina-eosina) pode tornar-se difícil, sendo necessários marcadores imunoistoquímicos mioepiteliais. Até o momento, nenhum marcador mostrou-se, isoladamente, sensível e específico o bastante para auxiliar de maneira fidedigna em dilemas diagnósticos específicos, especialmente em: (1) lesões esclerosantes benignas vs. carcinoma tubular e (2) neoplasias papilíferas. No presente trabalho, dois novos marcadores mioepiteliais (p63 e CD10) foram testados e comparados com marcadores tradicionalmente empregados em patologia cirúrgica (1A4 e calponina). No primeiro dilema diagnóstico, foram estudados 10 casos de adenose esclerosante, 10 casos de cicatriz radiada e 10 casos de carcinoma tubular. Todos os marcadores demonstraram expressão nas CMEs de todas as lesões benignas e foram consistentemente negativos nos casos de carcinoma tubular, porém, p63 e CD10 mostraram maior especificidade. Os marcadores tradicionais mostraram positividade em células estromais em todos os casos de carcinoma tubular, sendo que esta reação-cruzada poderia causar problemas de interpretação ao simular uma camada de CMEs em quatro casos. Contudo, 1A4 mostrou uma positividade mais intensa e reprodutível nas CME. Concluímos, assim, que p63 e CD10 devem ser usados como anticorpos complementares ao 1A4 na distinção entre lesões esclerosantes benignas e carcinoma tubular da mama. No estudo das neoplasias papilíferas, foram avaliados 20 casos incluindo papilomas, papilomas atípicos e carcinomas papilíferos, além do tecido mamário normal adjacente. Todos os marcadores foram difusamente positivos no tecido mamário normal e papilomas, indicando sensibilidades semelhantes na identificação de CME. Uma positividade intensa foi encontrada em 100% dos casos corados para 1A4 e CD10, mas em apenas 76% e 60,5% dos corados para calponina e p63, respectivamente, sendo as diferenças estatisticamente significantes (p<0.05). Este dado sugere que os dois primeiros são tecnicamente mais reprodutíveis. Os marcadores mais específicos foram o p63 e CD10, mostrando reação-cruzada com células estromais em 0 e até 33% dos casos, respectivamente. Já os marcadores 1A4 e calponina mostraram reação-cruzada difusa em todos os casos. O CD10 mostrou uma combinação de uma maior especificidade e reprodutibilidade, com uma boa sensibilidade. Apesar de ser o mais específico, o p63 apresentou a menor sensibilidade e a impressão de uma camada de CMEs variavelmente interrompida (mesmo em tecido normal e lesões benignas), o que poderia causar problemas de interpretação. Além disto, o 1A4 mostrou-se também neste contexto, como o mais reprodutível tecnicamente. Assim sendo, no dilema diagnóstico das neoplasias papilíferas, defendemos o uso combinado do marcador CD10 com o 1A4. Em resumo, apesar de variarem em acurácia diagnóstica quando comparados entre si e com marcadores tradicionais, na dependência do dilema considerado, os novos marcadores testados neste trabalho parecem promissores no diagnóstico diferencial de lesões benignas e malignas da mama / Abstract: The myoepithelial cell (MEC) layer is usually present and continuous in normal breast tissue/benign lesions, and discontinuous to absent in atypical/malignant counterparts. Identifying MECs can be difficult on morphological grounds alone and currently relies on immunomarkers. So far, this detection has been carried out using antibodies such as alpha-smooth muscle actin (1A4) and calponin, but no immunomarker has proved to be accurate enough to identify MECs, particularly in specific diagnostic dilemmas such as: (1) benign sclerosing lesions vs. tubular carcinoma and (2) papillary neoplasms. The specificity of these markers has been questioned because they may be expressed in stromal myofibroblasts and vascular smooth muscle. Two novel myoepithelial markers have been described: the nuclear protein p63 and the surface antigen CD10. In the present study, we assessed the use of p63 and CD10 in comparison to the traditional markers in the specific diagnostic dilemmas specified above. In the first diagnostic problem, we studied 30 cases including sclerosing adenosis, radial scars and tubular carcinomas. All markers were expressed in MECs of all benign lesions and negative in all cases of tubular carcinoma. p63 and CD10 were mostly confined to MECs and thus more specific. Stromal positivity for 1A4 was present in all cases of tubular carcinoma and was misleading in 4 cases, as it simulated a MEC layer around malignant tubules. However, 1A4 was consistently more intensely expressed and thus more technically reproducible than the novel markers. So, we concluded that p63 and CD10 should be used as a complement to 1A4 in distinguishing benign sclerosing lesions from tubular carcinoma of the breast. Concerning the other diagnostic dilemma, we studied 20 cases of papillary neoplasms (including benign papillomas, atypical papillomas and papillary carcinomas), and adjacent normal breast tissue. All markers were diffusely positive in all samples of normal tissue and benign papillomas indicating similar sensitivities in the identification of MECs. Intense positivity was found in 100% of the cases stained with 1A4 and CD10, but in only 76% and 60,5% of those stained with calponin and p63, respectively; the differences were statistically significant (p<0.05), suggesting that the former two rendered more reproducible results. The most specific markers were p63 and CD10 which showed cross-reactivity in 0% and in up to 33% of the cases, respectively. 1A4 and calponin showed diffuse cross-reactivity in all cases. CD10 seems to combine the highest specificity and reproducibility with a good sensitivity. In spite of being the most specific, p63 was the least sensitive, also giving the impression of a discontinuous MEC layer even in normal tissue/benign lesions, which could potentially cause diagnostic problems. Moreover, in this context, 1A4 proved to be the most reproducible. Thus, a minimum panel for immunodetection of MEC to assess papillary lesions should include both markers. In conclusion, in spite of the variable accuracy depending on the diagnostic dilemma considered, the novel markers seem to be promising tools in the differential diagnosis between benign and malignant lesions of the breast / Doutorado / Anatomia Patologica / Doutor em Ciências Médicas

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No description available.