As a control, we crossed the αSMACreERT2 mice with the Rosa26-LSL-tdTomato line (referred to as αSMA-tdT mice) and injected PyMT cells into their MFP one day after the first tamoxifen injection to confirm the presence of αSMA-tdT+ cells exclusively at the tumor site, but not in the bone (Supplementary Fig. 3A). The gene discussed is ACTA1; the disease is neoplasm.