To study the radiosensitizing effects of AuNPs in vivo, we employed i.t. injection of HER2-targeted AuNPs in mice with s.c. MDA-MB-361 tumours to achieve a sufficient concentration of gold for radiosensitization (5–10 mg/g) (Cai et al. 2013). The gene discussed is ERBB2; the disease is neoplasm.