Study in ER/PR and HER2 receptor IHC

Abstract

Recently, the development of Estrogen Receptor (ER), Progesterone Receptor (PR), and Human Epidermal Growth Factor Receptor 2 (HER2) receptors in immunohistochemistry has amassed significant prognostic value in the treatment of breast carcinomas. Its introduction provides an inexpensive and widely available testing protocol yielding vital pathological information regarding patient outcome and therapeutic response. However, in conjunction with its continued advancement, these markers withstand increased hindrance in reaching their full diagnostic potential due to the lack of a standardized protocol. The primary focus of this study was to develop standardized protocols for each breast marker. Through manipulation of antigen retrieval methods and dilutions, highly accurate and reproducible staining results were achieved. Validations of ER and PR were run with alternating Heat Induced Epitope Retrieval (HIER) methods using solutions buffered with EDTA and citrate. Simultaneous comparisons were run using the laboratory's Ventana platform, establishing parallels between previously validations and new optimizations to ease antibody transition. HER2 optimization initial workups included Dako, Thermo Fisher, and Ventana antibodies monitored over extended time periods . The finalized protocol utilizes Ventana's HER2 antibody validated to run on a Leica platform. The addition of an alternative hematoxylin counterstain and citric acid clarifier was applied in order to enhance staining clarity and ease of quantitation. The use of Ventana diluents in working antibody solution, restrictions on quantity made, and refrigeration, may create staining consistency. The laboratory used was able to offer a diagnostically significant receptor panel with minimal variations between cases, having an enormously positive impact on patient care.