Evaluation of Grading and Estrogen Receptors in Breast Cancer Using a Fully Automated Rapid Immunohistochemistry Based on Alternating Current Electric Field Technology

Background: Immunohistochemistry (IHC) is crucial for determining cancer treatments. We previously developed a rapid IHC method and have now developed a fully automated rapid IHC stainer (R-Auto). The aim of this study was to evaluate the clinical reliability of the R-Auto protocol for staining estrogen receptors (ERs) in breast cancer specimens and evaluated the staining performance. Methods: Between January 2015 and June 2020, 188 surgical specimens collected from breast cancer patients treated at our hospital were evaluated through ER staining using R-Auto, conventional manual (conventional) IHC and a commercial autostainer. The specimens were scored using Allred scores, after which the staining results were compared between R-Auto and the conventional IHC or commercial autostainer. Weighted kappa coefficients and AC1 statistics were used to assess the agreement between methods. Results: The AC1 statistic for comparison between R-Auto and conventional IHC was 0.9490 (0.9139-0.9841) with a 95.7% agreement rate and was 0.9095 (0.8620-0.9570) with a 92.6% agreement rate for comparison between R-Auto and the commercial autostainer. There was thus substantial agreement between R-Auto and both conventional IHC and the commercial autostainer. However, R-Auto shortened the time required for IHC from 209 minutes with conventional IHC to 121 minutes. Conclusions: R-Auto enables good staining performance in a shorter time with less effort.