With respect to in vivo models, a radioimmunoagent, 188Re‐SOCTA‐trastuzumab, which is formed by 188Re‐trastuzumab via the bifunctional ligand succinimidyl3,6‐diaza‐5‐oxo‐3‐[2‐((triphenylmethyl)thio)ethyl]‐8‐[(triphenylmethyl)thio]octanoate (SOCTA), strongly accumulated in tumour lesions in mice bearing xenografted HER2‐overexpressing BC tumours [85]. The gene discussed is ERBB2; the disease is breast cancer.