The receptor affinity of the [89Zr]Zr-p-NCS-Bz-DFO-anti-HER2 affibody was subsequently assessed in MCF-7 and BT-474 breast cancer cell lines to prove the utility of the proposed radiopharmaceutical for the accurate and highly specific identification of the HER2-positive tumours. The gene discussed is ERBB2; the disease is breast cancer.