Figure 1: Xenograft models of brain metastasis and primary breast cancer. (a) For models of brain metastasis, human breast cancer (231-Luc, HER2-60, and HER2-90) or melanoma (MeWo, WM3734) cell lines (or PBS as a control) were injected into the left ventricle of female immunodeficient mice. For models of primary breast cancer, human 231-Luc or HCC1937 cells were orthotopically injected into mammary fat pads. (b) Hematoxylin-eosin staining of mouse brain tissue with metastases formed by 231-Luc, MeWo, or WM3734 cells. Arrows indicate human metastatic cancer cells. Scale bars, 200 μm.