Despite the gene expression signature being derived from a HER2+ panel of cell lines, we found no subtype specificity for these two genes across HER2, Luminal A, Luminal B and Basal breast cancer subtypes in the METABRIC cohort (data not shown), indicating the general applicability of the in vitro cell adhesion phenotypic screen to discover prognostic factors independent of subtypes. This evidence concerns the gene ERBB2 and breast cancer.