Within the ISH-equivocal breast cancer patients whose cancers were upgraded to ISH-positive using alternative control probes, there was no subgroup of patients who had a significantly worse disease-free or overall survival compared with either the overall ISH-equivocal or ISH-negative patients or those with a HER2-to-alternative control probe ratio of less than 2.0 (Figure 3) (eTable 3 and eFigure 3 in the Supplement). The gene discussed is ERBB2; the disease is breast cancer.