ERBB2 and breast cancer: From the same database, we also compared the OS of 33 MpBC patients to 7515 non-metaplastic breast cancer patients (including HR+, HER2+, and TNBC) and found MpBC had a poorer OS (HR 11.5, 95% CI 3.64–36.35) than non-metaplastic breast cancer (Fig. 3).