ERBB2 and breast cancer: Median OS in these studies ranged 8.3–20.0 months (15, 16, 24, 27–31).We have reported a prospective multi-center phase II study of apatinib single or combination with endocrine therapy in HER2 negative breast cancer involving chest wall metastasis, the median PFS was 4.9 (95% CI: 2.1−8.3) months (29).