Yoshida et al.13 reported decreased tumor growth in NOD scid gamma (NSG)mice locally injected into the ducts of the mammary gland with [225Ac]Ac-DOTA-trastuzumab IgG (1.1–4.4 kBq) for treatmentof SUM225 HER2-positive ductal carcinoma in situ (DCIS).13 Howe et al.14 reportedRIT of HER2-positive BT-474 human BC xenografts in NCR nu/nu miceby intravenous (i.v.)injection of 4.6 or 9.2 kBq of [225Ac]Ac-DOTA-trastuzumab IgG or alternatively, [225Ac]Ac-DOTAincorporated into a pH-responsive liposome. The gene discussed is ERBB2; the disease is ductal breast carcinoma in situ.