RESUMO
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.