In a previous in silico dosimetric modeling study, we found that lead-212 (212Pb), a novel alpha-particle emitting radionuclide proposed for theranostic applications, when combined with an antibody against VCAM-1 would be suitable for the treatment of early BM.12 It was found that during the early micrometastatic stages of a breast cancer BM model, tumor cells grew co-optively around blood vessels with a maximum penetration depth of ≤47.8 μm from VCAM-1 expressing at 21 days after intracardiac injection of human breast carcinoma cells (MDA231BR-GFP). The gene discussed is VCAM1; the disease is breast cancer.