ERBB2 and ductal breast carcinoma in situ: In agreement with previous studies, this study verified that PD‐IDC and PD‐DCIS have a more negative HR ratio and more positive HER2 ratio than the corresponding cancers without PD.6, 7, 8, 9, 15, 16 Surprisingly, our univariate and multivariate Cox regression analyses showed that the HR status, HER2 status, and the combined molecular subtype were irrelevant to the prognoses of both PD‐IDC and PD‐DCIS.