Estudo imunoistoquímico comparativo entre os novos anticorpos monoclonais de coelho e anticorpos clássicos para avaliação dereceptores hormonais em câncer de mama usando arrays de tecidos

Abstract

Introduction: Immunohistochemistry analysis (IHC) for estrogen and progesterone receptors (ER and PR) in breast cancer is a well established predictive factor of anti-estrogen therapy. However, there is a large variable choice of antibodies and no agreement about the best antibodies to be used. A novel generation of rabbit monoclonal antibodies (Rab Mab) has been released recently. Aims: In this study,we compared the performance of the novel RabMab to Mab using an alternative tissue arrayer. Methods: We used non-commercial equipment that consists of a work station (DremelÒ) 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. Histological sections were immunostained using anti-ER Mab (1D5 and 6F11) and RabMab (SP1 and B644), and anti-PR Mab (PgR312 and PgR636) and RabMab (SP2 and B645). The intensity of the reaction and the background were semiquantitatively evaluated and the tumors in which more than 10% of the tumor cell nuclei stained was considered positive. Results and conclusions: The equipment and technique used in the present study represent an economical alternative when compared to commercialequipment. The slides showed fine tissue preservation, adequate for morphologic evaluation, and sufficient to confirm diagnosis. The comparative analysis of the RabMab anti-ER and anti-PR showed more sensibility compared to clone 1D5 and concordance with clone 6F11 and represent a reliable alternative to Mab for IHC evaluation of breast tumors. RabMab anti-PR were more sensitive than Mabs.