Bastiaannet et al. [57] reported dose-dependent RBE values for alpha-emitter radiopharmaceutical therapy with 212Pb, which decays to alpha-emitting 212Bi, ranging between 9 and 17.5 derived from surviving fractions of the HER2 + breast cancer cell line treated with a 212Pb-labeled anti-HER2 conjugate or external beam radiotherapy (EBRT). This evidence concerns the gene ERBB2 and breast cancer.