Morphologic analysis of brain deposits stained with anti-HER-2 antibody (Figure 2) showed that mice implanted with MDA-MB-453 (Fig. 2A-B) or BT-474 (Figure 2C) cells had multiple metastases with a distribution recapitulating the clinical situation observed in breast cancer patients developing brain metastasis. The gene discussed is ERBB2; the disease is breast carcinoma.