Expression of EGF receptors in canine prostate with proliferative inflammatory atrophy and carcinoma / Expressão de receptores EGF na próstata canina com atrofia inflamatória proliferativa e carcinoma

ABSTRACT: Gene expression of ErbB1 and ErbB2, and immunostaining of EGFR (Her1) and Her2 (c-erbB-2) were evaluated in this study to ascertain whether these receptors are involved in the evolution of canine premalignant and malignant prostatic lesions, as proliferative inflammatory atrophy (PIA) and prostatic carcinoma (PC). With regards to the intensity of EGFR immunostaining, there was no difference between normal prostatic tissue and tissues with PIA or PC. In relation to Her2 immunostaining, there were differences between normal prostatic tissue and those with PIA and PC, as also differences between prostates with PIA and PC. There was no correlation between EGFR and Her2 immunostaining. ErbB1 gene product was detected in two normal tissue samples, in one with PIA, and in all samples with PC. ErbB2 mRNA was recorded in two canine samples with PIA, in all with PC, but was not detected in normal prostatic tissue. It was concluded that EGFR and Her2 play roles in canine PIA and PC, suggesting that those receptors may be involved in canine prostatic carcinogenesis.

RESUMO: A expressão gênica de ErbB1 e ErbB2 e a imunomarcação de EGFR (Her1) e Her2 (c-erbB-2) foram avaliadas para verificar o envolvimento desses receptores em lesões pré-malignas e malignas da próstata canina, como a atrofia proliferativa inflamatória (PIA) e o carcinoma prostático (PC). Em relação à intensidade de imunomarcação para EGFR, não houve diferença entre o tecido prostático normal e com PIA e PC. Em relação a Her2, observou-se diferença de imunomarcação entre o tecido prostático normal e aqueles com PIA e PC e entre os com PIA e PC. Não houve correlação entre EGFR e Her2. O gene ErbB1 foi detectado em duas amostras normais, uma de PIA e em todas as amostras de PC. O gene ErbB2 foi detectado em duas amostras de PIA e em todas as amostras de PC, não sendo detectado no tecido prostático normal. Conclui-se que EGFR e Her2 atuam nas lesões de PIA e PC, sugerindo o envolvimento destes na carcinogênese da próstata canina.

Avaliacao comparativa entre os metodos objetivo e subjetivo em laminas coradas pela imuno-histoquimica / Comparative assessment between objective and subjective methods in slides stained by immunohistochemistry

Métodos objetivos de avaliação são frequentemente cobrados em estudos científicos. Exames histológicos com coloração imuno-histoquímica podem ser avaliados por meio de fotometria. OBJETIVO: Comparar este método objetivo com a avaliação subjetiva realizada por três observadores independentes, utilizando lâminas de colesteatoma adquirido da orelha média. MÉTODO: Foram selecionadas um total de 54 imagens de colesteatomas imuno-histoquimicamente coradas pelos anticorpos anti-TNF-R2 (32 lâminas) e anti-TGF-α; (22 lâminas). O anticorpo secundário utilizado nos dois grupos foi o Max Polimer Detection System (Kit Novo Link, Novocastra®, UK). As amostras foram processadas por um scanner digital de lâminas (modelo ScanScope - Aperio). As áreas selecionadas foram submetidas à análise por fotometria. RESULTADOS: A avaliação objetiva por fotometria foi comparada com a avaliação subjetiva por três observadores e submetidas à análise estatística. A análise estatística revelou reprodutibilidade moderada (K valores entre 0,41 e 0,60) para os dois grupos. CONCLUSÃO: O presente estudo demonstrou que as características irregulares das lâminas de colesteatoma da orelha média coradas pela imuno-histoquímica impossibilita a sua adequada avaliação objetiva, enquanto a avaliação subjetiva por observadores experientes se mostrou mais confiável. .

Objective methods of assessment are often required in scientific studies. Histological tests with immunohistochemical staining can be assessed by photometry. OBJECTIVE: To compare this objective method with the subjective evaluation performed by three independent examiners, using slides of acquired middle ear cholesteatomas. METHOD: We selected a total of 54 cholesteatoma images, immunohistochemically stained by anti-TNF-R2 (32 slides) and anti-TGF-α, (22 slides). The secondary antibody used in the two groups was the Max Polymer Detection System (Novo Link Kit, Novocastra®, UK). The samples were processed by a digital slide scanner (ScanScope - Aperio). The selected sites were analyzed by photometry. RESULTS: The objective assessment by photometry was compared with the subjective evaluation by three examiners and subjected to statistical analysis. The Statistical analysis revealed moderate reproducibility (K values between 0.41 and 0.60) for both groups. CONCLUSION: Our study showed that the irregular characteristics of middle ear cholesteatoma slides stained by immunohistochemistry prevents its proper objective evaluation, while the subjective assessment by experienced examiners was more reliable. .

Immunohistochemical profile of high-grade ductal carcinoma in situ of the breast

OBJECTIVE: To determine the frequency of the immunohistochemical profiles of a series of high-grade ductal carcinoma in situ of the breast. METHODS: One hundred and twenty-one cases of high-grade ductal carcinoma in situ, pure or associated with invasive mammary carcinoma, were identified from 2003 to 2008 and examined with immunohistochemistry for estrogen receptor, human epidermal growth factor receptor 2, cytokeratin 5, and epidermal growth factor receptor. The tumors were placed into five subgroups: luminal A, luminal B, HER2, basal-like, and “not classified”. RESULTS: The frequencies of the immunophenotypes of pure ductal carcinoma in situ were the following: luminal A (24/42 cases; 57.1%), luminal B (05/42 cases; 11.9%), HER2 (07/42 cases; 16.7%), basal-like phenotype (00/42 cases; 0%), and “not classified” (06/42 cases; 14.3%). The immunophenotypes of ductal carcinoma in situ associated with invasive carcinoma were the following: luminal A (46/79 cases; 58.2%), luminal B (10/79 cases; 12.7%), HER2 (06/79 cases; 7.6%), basal-like (06/79 cases; 7.6%), and “not classified” (11/79 cases; 13.9%). There was no significant difference in the immunophenotype frequencies between pure ductal carcinoma in situ and ductal carcinoma in situ associated with invasive carcinoma (p>0.05). High agreement was observed in immunophenotypes between both components (kappa=0.867). CONCLUSION: The most common immunophenotype of pure ductal carcinoma in situ was luminal A, followed by HER2. The basal-like phenotype was observed only in ductal carcinoma in situ associated with invasive carcinoma, which had a similar phenotype. .

Immunohistochemical expression of CD44s in renal cell carcinoma lacks independent prognostic significance

PURPOSE: To analyze the immunohistochemical expression of the standard isoform of CD44 (CD44s) adhesion molecule in clear cell renal cell carcinoma (CCRCC) and its impact on clinical outcomes. MATERIALS AND METHODS: Ninety-nine consecutive patients treated surgically for RCC between 1992 and 2009 were selected. A single pathologist reviewed all cases to effect a uniform reclassification and determine the most representative tumor areas for construction of a tissue microarray. The same pathologist, who was blinded to the outcome of the cases, semi-quantitatively scored the staining intensity of CD44s in all specimens. The counting was done using the H-Score algorithm. RESULTS: Of the 99 immunostained RCC specimens, 57(57.7%) showed low expression, and 42(42.4%) showed high expression levels of CD44s. The expression of CD44s was directly associated with tumor size (p = 0.03), clinical stage (p = 0.02) and Fuhrman grade (p = 0.02). Disease specific survival (DSS) rates for patients whose specimens expressed low and high levels of CD44s was 88.1% and 67.5%, respectively (p = 0.009). Progression free survival (PFS) rates in patients with low and high expression of CD44s were 78.8% and 61.7%, respectively (p = 0.05). Classical features such as the presence of metastasis and clinical stage remained isolated predictors of survival. CONCLUSIONS: Immunohistochemical expression of CD44s was associated with important clinical variables such as stage and Fuhrman grade. However, it was not an independent predictor of survival. Therefore, we believe it has a limited role as a prognostic marker in patients with CCRCC.

Is polysomy 17 an important phenomenon to predict treatment with trastuzumab in breast cancer?

OBJECTIVES: Polysomy has been reported in 8 to 68% of invasive breast carcinomas. Polysomy 17 is frequently found in breast cancer and may complicate the interpretation of HER2 testing results. Abnormalities of chromosome 17 can lead to discrepant interpretations of FISH data. This study aimed to review the impact of polysomy 17 on HER2 testing and studied its clinicopathologic significance in relation to HER2 gene amplification and predicted treatment with trastuzumab. MATERIAL AND METHODS: A literature review was performed on polysomy 17 to clarify the significance of chromosome 17 polysomy in invasive breast cancer and show how the increase of CEP17 copy number is currently assessed for novel polysomy 17 testing techniques. CONCLUSIONS: Polysomy 17 tumors cannot be distinguished from HER2-negative tumors by standard pathologic criteria, including tumor grade and hormone receptor status. The literature indicates that HER2-directed therapy does not add benefit to cytotoxic chemotherapy in metastatic HER2 FISH-negative patients with polysomy 17; however, there is still controversy concerning clinical responses to trastuzumab in those specific cases. Accordingly, more studies with chromosome 17 polysomy and FISH negative are required.

The use of the immunohistochemical biotin-free visualization systems for estrogen receptor evaluation of breast cancer

Background: A novel generation of immunohistochemical visualization systems based on a biotin-free polymeric (BFP) technology has recently been released. We have compared the new BFP and the classical streptavidin-biotin (SAB) systems to evaluate estrogen receptor in breast carcinomas. Methods: Serial sections from a tissue microarray containing 320 invasive breast carcinomas were stained by immunohistochemistry for estrogen receptor using the rabbit monoclonal antibody SP1. Eleven different visualization systems were used, including seven BFP systems (six second-generation: DAKO Advance TM , Leica Novolink TM, Zymed SuperPicTureTM , Zymed PicTure Max TM , Biogenex Super Sensitive Non-Biotin HRP TM , CellMarque Mouse/Rabbit Polydetector HRP/DABTM ; one first-generation: DAKO EnVision+TM) and four SAB systems (DAKO LSAB+TM ; Signet EasyPathTM ; Biogenex Super SensitiveTM and CellMarque Mouse/Rabbit Immunodetector HRP/DABTM). All visualization systems were used following the instructions provided by the manufacturers. All slides were scanned using Zeiss Mirax Scan™, and the intensity of immunohistochemistry staining was automatically quantified using HistoQuant™ software. The cytoplasm staining was visually evaluated as absent (0), weak (1), moderate (2), or strong (3). Results: The BFP Advance and Novolink , and the SAB LSAB + showed the highest staining intensity among all the systems (P<0.01). However, LSAB+ showed the highest cytoplasm staining among those used (p<0.01). .. The BFP Advance and Novolink showed the strongest staining intensity and, followed by all the other second-generation BFPs, represent a powerful tool for immunohistochemistry standardization of estrogen receptor evaluation of breast carcinomas.

Rabbit antibodies for hormone receptors and HER2 evaluation in breast cancer / Anticorpos de coelho para avaliação de receptores hormonais e HER2 em câncer de mama

BACKGROUND: Novel rabbit monoclonal antibodies (RabMab) for estrogen (ER), progesterone (PR) receptors and HER2 evaluation by immunohistochemistry have recently been commercially released. We compared the RabMab anti-ER, anti-PR and anti-HER2 to mouse monoclonal antibodies (Mab) using tissue microarrays (TMA) of breast carcinomas. METHODS: Two TMA containing breast carcinomas were built. Sections were immunostained using anti-ER and anti-PR, Mab and RabMab. The sections stained for ER and PR were evaluated considering positive those tumors in which more than 1 percent of the tumor cell nuclei stained moderate or strong. For HER2, the immunostained sections were evaluated using the ASCO/CAP guidelines for HER2. Chromogenic in situ hybridization (CISH) was used as the gold standard for HER2 evaluation. CISH was evaluated using the Zymed HER2 CISH interpretation guidelines. RESULTS: RabMab against ER have similar staining patterns compared to the 6F11 (Mab), but stronger than 1D5 (Mab) from three different suppliers. The RabMab against PR provide stronger and sharper immunohistochemical signals compared to Mab. The detection of HER2 protein overexpression was more prevalent with the polyclonal antibodies and RabMab than with the Mab. These were more specific than the RabMab, which were more sensitive when compared to CISH. CONCLUSION: The novel RabMab against ER and PR showed higher intensity of staining than the Mab. The RabMab against HER2 is more sensitive than Mab, however, Mab presented more specificity than RabMab when compared to CISH for HER2 evaluation of breast carcinomas.

OBJETIVOS: Novos anticorpos monoclonais de coelho (RabMab) para a avaliação imuno-histoquímica de receptores de estrógeno (RE), progesterona (RP) e HER2 foram lançados comercialmente. Comparamos os RabMab anti-RE, anti-RP e anti-HER2 com os anticorpos monoclonais de camundongo (Mab) utilizando tissue microarrays (TMA) de carcinomas de mama. MÉTODOS: Foram construídos dois TMAs de carcinomas de mama. As secções foram marcadas usando anti-RE, anti-RP e anti-HER2, Mab e RabMab através de imuno-histoquímica. As secções marcadas para RE e RP foram avaliadas considerando positivos aqueles tumores nos quais mais de 1 por cento dos núcleos coraram moderadamente ou forte. Para HER2, as secções foram avaliadas utilizando as recomendações da ASCO/CAP para HER2. Hibridização in situ cromogênica (CISH) foi usada como padrão-ouro para avaliação de HER2. CISH foi avaliado utilizando as recomendações da Zymed. RESULTADOS: Os RabMab anti-RE apresentam intensidade de coloração semelhante ao 6F11 (Mab), porém maior que o 1D5 (Mab) proveniente de três diferentes fabricantes. Os RabMab anti-RP apresentaram sinal imunoistoquímico mais forte e delimitado comparado aos Mab. A detecção da superexpressão da proteína HER2 foi mais prevalente entre os anticorpos policlonais e RabMab, que se mostraram mais sensíveis quando comparados com o CISH. CONCLUSÃO: Os novos RabMab anti-RE e RP proporcionaram maior intensidade de coloração que os Mab. O RabMab anti-HER2 apresentou maior sensibilidade que os Mab, porém os Mab apresentaram maior especificidade quando comparados com o CISH para a avaliação de HER2 em carcinomas de mama.

Predictive factors of breast cancer evaluated by immunohistochemistry: [review] / Fatores preditivos do câncer de mama avaliados pela imuno-histoquímica: [revisão]

Hormone receptor and Her2 protein overexpression evaluated by immunohistochemistry (IHC) is widely validated as a predictive factor in breast cancer. The quality of the IHC reaction is influenced by tissue fixation and processing. Over- and underfixation deeply affect IHC results. Antigen retrieval may improve IHC but it does not recover tissue from autolysis or overfixation. The choice of primary antibody for IHC as to its sensitivity and specificity in relation to therapeutic response represents an important stage. Apart from mouse monoclonal antibodies, new rabbit monoclonal antibodies are commercially available, such as clones anti-ER SP1 and B644, anti-PR SP2 and B645 and anti-Her2 SP3 and 4B5. They represent an alternative to hormone receptor and Her2 evaluation by IHC. New polymeric non-biotinylated detection systems are also available and allow accurate and strong marking with no stromal and no non-specific cytoplasmic staining due to endogenous biotin. The most recommended cut off for estrogen and progesterone receptors (ER and PR) is more than 1 percent of positive cells with moderate or strong staining intensity (Allred's scoring system). New guidelines for Her2 evaluation by IHC show a cut off of more than 30 percent of positive cells with strong intensity (3+) that correlates better with gene amplification. The 2+ cases are now considered indeterminate and should be confirmed by fluorescence in situ hybridisation (FISH) or chromogenic in situ hybridisation CISH. A quality control of pre-analytical, analytical and post-analytical phases of IHC is recommended in order to optimize results.

A superexpressão de receptores hormonais e Her2 avaliada pela imuno-histoquímica (IHQ) é amplamente validada como fator preditivo em câncer de mama. A qualidade da reação imuno-histoquímica é influenciada pela fixação do tecido e seu processamento. A fixação insuficiente ou demasiada afeta profundamente os resultados da IHQ. A reativação antigênica pode melhorar os resultados da IHQ, porém não recupera tecidos com autólise ou com excessiva fixação. A escolha do anticorpo primário para a IHQ, considerando sua sensibilidade e sua especificidade de acordo com a resposta terapêutica, representa uma importante etapa. Além de anticorpos monoclonais de camundongo, novos anticorpos monoclonais de coelho são comercialmente disponíveis, tais como clones SP1 e B644 anti-RE, SP2 e B645 anti-RP, e SP3 e 4B5 anti-Her2. Eles representam uma alternativa para avaliação de receptores hormonais e Her2 através da IHQ. Novos sistemas de detecção poliméricos não-biotinilados também são disponíveis e permitem marcação exata e forte sem marcação estromal ou citoplasmática inespecífica devido à biotina endógena. O cut off mais recomendado para receptor de estrogênio (RE) e receptor de progesterona (RP) é acima de 1 por cento de células positivas com marcação moderada ou forte (sistema de escore de Allred). Novas recomendações para avaliação de Her2 através da IHQ apontam um cut off de mais de 30 por cento de células positivas com marcação forte (3+), que melhor se relaciona com amplificação gênica. Os casos 2+ são agora considerados indeterminados e devem ser confirmados por hibridação in situ por fluorescência (FISH) ou hibridização in situ colorimétrica (CISH). Um controle de qualidade de fases pré-analítica, analítica e pós-analítica da IHQ é recomendado para a otimização dos resultados.

A comparison between the novel rabbit monoclonal antibodies (SP1 and B644) and mouse antibodies for evaluating estrogen receptor in breast tumors / Uma comparação entre os novos anticorpos monoclonais de coelho (SP1 e B644) e anticorpos de camundongo para detecção de receptores de estrógeno em carcinomas mamários

BACKGROUND: A novel generation of rabbit monoclonal antibodies has been released recently for estrogen (ER) and progesterone (PR) receptor evaluation in breast cancer by immunohistochemistry. Aims: We compared novel rabbit monoclonal antibodies anti-ER SP1 (LabVision®) and B644 (Cell Marque®) to mouse monoclonal antibodies 1D5 (Dako®) and 6F11 (Novocastra®) using a tissue microarray of breast carcinomas. METHODS: Two cylinders (2 mm diameter) of formalin-fixed paraffin embedded tissue were obtained from 24 invasive breast carcinomas and immunostained by using the anti-ER rabbit and mouse antibodies and the streptavidin-biotin detection system (Biogenex®). Immunostaining was evaluated considering positive those tumors in which more than 10 percent of the tumor cell nuclei stained. The stain intensity was also evaluated as weak (1), moderate (2), and strong (3). Results: Both rabbit antibodies against ER have similar staining pattern to each other and also to 6F11, but significantly stronger scores compared to mouse 1D5. The rabbit antibodies allow better cost/benefit because of higher working dilutions compared to mouse antibodies using the same procedure. CONCLUSION: The new rabbit antibodies against ER are highly sensitive and reliable in clinical and research immunohistochemical testing of breast carcinomas.

INTRODUÇÃO: Uma nova geração de anticorpos monoclonais de coelho tem sido produzida para detecção de receptores de estrógeno (RE) e progesterona (RP) pela imuno-histoquímica em câncer de mama. OBJETIVO: Comparamos os novos anticorpos monoclonais de coelho anti-RE SP1 (LabVision®) e B644 (Cell Marque®) com anticorpos monoclonais de camundongo 1D5 (DAKO®) e 6F11 (Novocastra®) utilizando um tissue microarray de carcinomas mamários. METODOLOGIA: Dois cilindros (2 mm de diâmetro) de tecido fixado em formol e embebido em parafina foram retirados de 24 carcinomas mamários invasivos e corados pela imuno-histoquímica utilizando-se os anticorpos de coelho e de camundongo anti-RE e o sistema de detecção estreptavidina-biotina peroxidase (Biogenex®). A coloração imuno-histoquímica foi avaliada considerando positivos os tumores nos quais mais de 10 por cento dos núcleos das células tumorais estivessem corados. A coloração também foi classificada em fraca (1), moderada (2) e forte (3). RESULTADOS: Ambos os anticorpos monoclonais de coelho contra RE apresentaram intensidade de coloração semelhante àquela pelo anticorpo de camundongo 6F11, porém os anticorpos de coelho apresentaram intensidades de coloração significativamente mais fortes que as do clone de camundongo 1D5. As altas diluições possíveis utilizando anticorpos de coelho permitem melhor custo/benefício quando comparadas com as diluições possíveis utilizando anticorpos de camundongo. CONCLUSÃO: Os novos anticorpos monoclonais de coelho anti-RE são altamente sensíveis e fidedignos para testes imuno-histoquímicos tanto para a clínica quanto para pesquisa de tumores mamários.

Concordância interobservador na interpretação imuno-histoquímica da superexpressão do Her2 detectada por cinco diferentes anticorpos em array de carcinomas mamários / Interobserver agreement in scoring immunohistochemical overexpression of Her2 detected by five different antibodies on tissue microarrays of breast carcinomas

OBJETIVO: Estudar a concordância interobservador na interpretação da superexpressão imuno-histoquímica para a proteína Her2 empregando diferentes anticorpos em array de carcinomas mamários. MATERIAL E MÉTODO: Foi construído um array contendo dois cilindros (2 mm de diâmetro cada) de 25 carcinomas mamários. Cortes histológicos seriados do array foram submetidos à imuno-histoquímica utilizando-se cinco anticorpos anti-Her2: SP3 (NeoMarkers), HercepTest e A0485 (Dako), CB11 (Novocastra) e 4D5 (Genentech). Uma lâmina corada por cada anticorpo (total = cinco lâminas) foi submetida à avaliação individual por cinco observadores seguindo-se o sistema de escore proposto no HercepTestTM. Para a avaliação interobservador os resultados foram interpretados em três diferentes análises: I (0; 1+; 2+; 3+); II (0 e 1+; 2+ e 3+) e III (0 e 1+; 2+; 3+) e aplicado o teste estatístico de kappa. RESULTADOS: A concordância interobservador foi boa quando os casos foram avaliados em quatro categorias (0; 1+; 2+; 3+). Quando avaliados em duas categorias (0 e 1+; 2+ e 3+), a concordância interobservador foi boa para os casos corados por SP3 e CB11 e muito boa para os corados por A0485, HercepTest e 4D5. Na análise III (0 e 1+; 2+; 3+), a concordância interobservador foi considerada moderada para os casos corados por CB11 e boa para os corados pelos outros anticorpos. CONCLUSÃO: A concordância interobservador foi considerada entre moderada e muito boa na avaliação dos cinco anticorpos. A menor concordância interobservador ocorreu nos casos com marcações fraca (1+) e moderada (2+). A experiência dos observadores influenciou as taxas de concordância.

AIM: To examine interobserver agreement in immunohistochemical evaluation of Her2 overexpression using five different antibodies on breast cancer array. MATERIAL AND METHOD: Material and method: One array was built with two cores (2 mm diameter each) from 25 breast carcinomas. Serial sections from the array were submitted to immunohistochemistry using five anti-Her2 antibodies: SP3 (NeoMarkers), HercepTest and A0485 (Dako), CB11 (Novocastra), and 4D5 (Genentech). One slide immunostained for each antibody (total = five slides) were independently scored by five observers following HercepTestTM scoring system. Interobserver agreement was evaluated in three different analysis: I (0; 1+; 2+; 3+); II (0 and 1+; 2+ and 3+) and III (0 and 1+; 2+; 3+), and the kappa statistics was applied. RESULTS: There was a good rate of interobserver agreement when the four scores were considered (0; 1+; 2+; 3+). When the scores were considered in two categories (0 and 1+; 2+ and 3+) the interobserver agreement rate was considered substantial for cases stained for SP3 and CB11, and almost perfect for cases stained for A0485, HercepTest and 4D5. For analysis III (0 and 1+; 2+; 3+), a moderate rate of interobserver agreement was considered for cases stained for CB11, and a substantial rate for other antibodies. CONCLUSION: The overall interobserver agreement was considered moderate to substantial in the evaluation of cases stained for the five antibodies. The lowest rate of agreement was obtained in the evaluation of the cases scored as weak (1+) and moderate (2+). The observers experience altered the concordance rates.

Construção de arrays de tecido com equipamento alternativo e de baixo custo para estudo imuno-histoquímico de tumores mamários / Construction of low cost tissue microarrays using alternative equipment for immunohistochemical study of breast tumors

INTRODUÇÂO: Tissue microarrays (TMA) são blocos contendo numerosos cilindros de tecido parafinado organizados em linhas e colunas que permitem analisar muitas amostras numa única lâmina. Equipamentos disponíveis comercialmente são importados e têm alto custo (entre 11 e 24 mil dólares). OBJETIVOS: Descrever uma forma alternativa de construção de arrays de tumores mamários de baixo custo e relatar nossa experiência na sua utilização em estudo imuno-histoquímico (IIQ). METODOLOGIA: Utilizou-se modelo que consiste numa minirretífica com agulha de biópsia hepática de 2mm de diâmetro acoplada à bancada com suporte (Dremel). Inicialmente preparou-se o bloco receptor fazendo o número de furos desejável (55). Cilindros de tecido foram obtidos com o mesmo dispositivo e colocados nos orifícios do bloco receptor. De cada bloco doador, obteve-se dois cilindros de diferentes áreas representativas do tumor. Em cada array foram incluídos cilindros de tumor (controle positivo e negativo) para cada anticorpo testado na IIQ, e cilindro marcador de iniciação da leitura da lâmina (fígado). Cortes sequenciais de 4µm obtidos do array foram submetidos à IIQ. A primeira e a última lâmina foram coradas pela hematoxilina e eosina (HE) para avaliar: número de discos de tecido, preservação tecidual e adequabilidade da amostra. Foi realizada IIQ empregando anticorpos anti-receptores de estrógeno, progesterona, Ki67, p53 e Her2. RESULTADOS: O custo total do equipamento foi apenas US$180,00. Cortes histológicos do array apresentaram boa preservação tecidual, sendo adequados para avaliação morfológica e suficientes para confirmação diagnóstica. A qualidade das realizações IIQ foi semelhante à obtida nos blocos doadores. CONCLUSÃO: Esse equipamento e a técnica representam uma alternativa econômica aos equipamentos comerciais.

BACKGROUND: Tissue microarrays (TMA) are blocks containing numerous cylinders of paraffinized tissue organized in lines and columns allowing analysis of numerous samples in one slide. Commercially available equipment is imported and have high cost (US$ 11,000.00 to 24,000.00). AIM: we describe a low cost breast-tumor TMA and our experience in its use for immunohistochemistry (IHC). MATERIAL AND METHODS: A model that consists of a work station (Dremel) to which a liver biopsy needle of 2mm of diameter was connected. A receptor block was prepared perforating it until the desired number of rows (55) was reached. Then, the cylinders of tissue were obtained using the same equipment and included in the holes of the receptor block. Two samples were obtained from different tumor areas of each donor block. Cylinders of previously tested positive control tumors for each antibody and one marker (liver sample) that indicated the beginning of slide reading were also included. IHC was performed in sequential 4µm sections from the same array using antibodies against estrogen and progesterone receptors, Ki67, p53 and Her2. The first and the last slides were stained by hematoxylin and eosin to evaluate: number of tissue discs, tissue preservation, and adequacy of the tissue sample. RESULTS: The equipment total cost was US$ 180,00. The slides showed fine tissue preservation, adequate for morphologic evaluation, and sufficient to confirm diagnosis. The IHC quality was similar to the donor blocks. CONCLUSION: This equipment and technique represent an economical alternative when compared to commercial equipments.