The results showed that the fluorescently labelled HER3-specific Affibody molecules (Z05416 and Z05417) bound to the HER3-positive breast cancer cell lines MCF-7 and SKBR-3, but not to the HER3-negative/HER2-positive SKOV-3 cell line (Fig. 1A–B). The gene discussed is ERBB2; the disease is breast carcinoma.