ERBB2 and breast cancer: Comparatively, HR + /HER2 + breast cancer metastasizes in bone (62.1% vs 43.4%, P < 0.0001) at the initial diagnosis, with a declining incidence of liver (35.0% vs 43.0%, P < 0.0001), lung (30.2% vs 35.4%, P = 0.011), and brain involvement (6.5% vs 9.4%, P = 0.008).