Yoshida et al. reported that the SF of HER2-positive SUM225-Luc + ductal carcinoma in situ of the breast (DCIS) cells was decreased to 0.15 by exposure to 3.7 kBq/mL of [225Ac]Ac-DOTA-trastuzumab (SA = 37 kBq/μg) compared to 0.91 for exposure to 3.7 kBq/mL of irrelevant [225Ac]Ac-DOTA-rituximab, demonstrating HER2 specific cell killing (Yoshida et al. 2016). This evidence concerns the gene ERBB2 and ductal breast carcinoma in situ.