Diminuição da expressão imuno-histoquímica de moléculasde adesão em carcinomas escamosos de mucosa oral / Reduction of immunohistochemical expression of adhesion molecules in squamous carcinoma of oral mucosa

Objetivos: Comparar a expressão imuno-histoquímica da E-caderina e da Beta-catenina de lesões escamosaspré-neoplásicas e neoplásicas de mucosa oral de amostras emblocadas em parafina. Materiais e métodos:Foram selecionadas 15 amostras de mucosa oral de pacientes apresentando hiperplasia com ou sem displasialeve (grupo 1); 5 amostras apresentando displasia moderada, acentuada ou carcinoma in situ (grupo 2); e12 amostras apresentando carcinoma de células escamosas invasor (grupo 3). Essas amostras foram submetidasà técnica de imuno-histoquímica com anticorpos primários monoclonais anti-E-caderina e anti-Betacatenina.A leitura em microscopia óptica compreendeu a expressão tecidual desses marcadores no epitélioescamoso das amostras de mucosa oral – lesadas ou não. A expressão imuno-histoquímica dessas moléculasde adesão foi classificada, segundo a sua intensidade de marcação tecidual, em negativa, positiva fraca epositiva forte. Resultados: A expressão de E-caderina foi forte em 93,3% dos casos do grupo 1 (hiperplasia/displasia leve), e 100% dos casos demonstraram forte expressão para a Beta-catenina nesse mesmo grupo. Contudo, no grupo 3 (carcinoma de célula escamosa), somente 42% dos casos foram fortemente positivospara E-caderina e 25% deles para Beta-catenina. Conclusões: A E-caderina e a Beta-catenina diminuíram asua expressão segundo a progressão tumoral do carcinoma de mucosa oral, reforçando um dos mecanismosrelacionados com a sua carcinogênese.

Objectives: To compare the immunohistochemical expression of E-cadherin and Beta-catenin in squamous pre-malignant and malignant lesions of formalin fixed paraffin embedded buccal mucosa samples. Materials e methods: Selected 15 samples of buccal mucosa of patients with hyperplasia with or without mild dysplasia (group 1), 5 samples showing moderate dysplasia, severe or carcinoma in situ (group 2) and 12 samples presenting invasive squamous cell carcinoma (group 3). These samples were subjected to immunohistochemistry with anti-E-cadherin and anti-Beta-catenin monoclonal antibodies. The expression of these markers in tissue samples injured or not were analyzed in accordance of positivity that was observed in epithelium stratum. The immunohistochemical expression of these adhesion molecules was classified according to their intensity in negative, weak positive and strong positive. Results: The expression of E-cadherin was strong at 93.3% of patients in group 1, and 100% of the cases showed strong expression of Beta-catenin in the same group. However, in group 3, only 42% of cases were strongly positive for E-cadherin and 25% of them to Beta-catenin. Conclusions: The E-cadherin and Beta-catenin decreased their expression according to tumor progression, from hiperplasia/mild dysplasia lesion to buccal invasive carcinoma and this fact may be related of the carcinogenesis mechanisms.

Alterations of E-cadherin and MMP-2 in cancer prostate

E-cadherin plays a crucial role in epithelial cell-cell adhesion and maintenance of tissue architecture. Alterations in expression or function of this protein result in loss of intercellular adhesion, with possible consequent increased tumor progression, metastasis, and poor prognosis in different cancer types. Matrix metalloproteinases [MMPs] constitute a multi-gene family of proteolytic enzymes that are capable of degrading connective tissue and almost all extracellular matrix components. Overexpression of MMPs is usually associated with the acquisition of invasiveness by tumor cells, cancer progression, angiogenesis and metastasis. To examine the expression of E-cadherin and MMP-2 in male prostatic lesions using immunohistochemical staining. 30 cases of formalin-fixed, paraffin embedded tissues of male prostatic lesions were examined for the expression of E-cadherin and MMP-2 using immunohistochemistry utilizing rabbit antihuman polyclonal antibodies for E-cadherin and MMP-2. The tissue specimens comprise samples of 25 prostatic adenocarcinoma [PAC] and five benign prostatic hyperplasia [BPH]. H and E histological examination revealed that of the 25 studied malignant cases, six were combined grade CG 10; three were CG9; two were CG8; three were CG7; four were CG6; and seven were CG5, according to combined Gleason's grading system. Immunostaining showed altered expression [cytoplasmic] of E-cadherin in poorly and moderately differentiated foci of carcinoma [CG6-10]. Cell membrane expression of E-cadherin was seen in well differentiated foci as well as in BPH. However for immunostaining of MMP-2, very weak expression of it was seen in BPH as well as in normal glands adjacent to tumor cells. Mild to moderate staining intensity was observed in well differentiated PAC and moderate intensity was seen in moderately differentiated PAC. Overexpression of MMP-2 in the form of positive cytoplasmic aggregates was shown in poorly differentiated PAC. The results suggest the implication of the altered expression of E-cadherin and MMP-2 in increased aggressiveness of the tumor with its subsequent increased invasiveness and progression. Also show that increased expression of collagenase type IV [MMP-2] and decreased expression of E-cadherin are associated with increasing Gleason score and that the expression of MMP-2 and E-cadherin exhibited strongest association with advanced prostate cancer