When making treatment decisions, how do you deal with conflicting results on HER2 measurement via IHC, FISH, and Oncotype Dx HER2 expression levels?

IHC and FISH are the standard-of-care assays for HER2 status determination, and treatment decisions should be based on IHC/FISH results rather than Oncotype DX HER2 mRNA expression levels when discordance exists (Tozbikian and Zynger, PMID 29498449; Neely et al., PMID 30230095). The Oncotype DX HER2...