We tested five breast cancer cell lines with different molecular profiles, i.e., MCF-7 (ER+/PR+), SKBR3 (HER2+), ZR-75-1 (ER+), MDA-MB-231 and MDA-MB-468 (both ER−/PR−/HER2−). The gene discussed is ERBB2; the disease is breast carcinoma.