The use of alternative probes is discouraged in the 2018 ASCO/CAP guidelines in view of the absence of outcome data.1 Recently, genomic profiling identified a small subset of HER2-enriched carcinomas among ISH group 4 carcinomas.8 Adjudication by these methods has not been associated with outcome after trastuzumab treatment. Here, ERBB2 is linked to carcinoma.