As a proof of principle that our findings obtained in SK-Br3, and BT474 cells could be reproduced in primary human ERBB2-BrCa, we established primary cell cultures from patient-derived-xenografts (PDX) developed from one ERBB2-positive patient and one ERBB2-negative BrCa patient, as control. Here, ERBB2 is linked to invasive breast carcinoma.