Additional file 1: Fig. S1. The experiment flow chart of this study was depicted. Fvb.B6 F1 female (brown color) hybrids were generated by crossing FVB/N-Tg(MMTV-PyMT)634Mul male (white color) mice to C57BL/6J female (black color) mice (Fig. S1A), Mammary tumors were harvested when the diameter of the largest tumor per mouse reached approximately 2 millimeters and 10 millimeters, which correspond to the Adenoma/MIN and late carcinoma stages. Lung metastases were harvested at the age of 13 weeks for Fvb mice and 16 weeks for F1 hybrids (Fig. S1B).