The remaining 78 cases (95 %) demonstrated low copy number gains and include 12 (80 %) ER−/PR−/HER2+ (range 10–68 % of tumor cells), 39 (64 %) ER−/PR−/HER2− (range 6–68 % of tumor cells), 21 (57 %) ER+/PR±/HER2− (range 6–69 % of tumor cells), and 6 (30 %) ER+/PR+/HER2+ cases (range 6–91 % of tumor cells) (Table 1). Here, ESR1 is linked to neoplasm.