While we did observe subtle differences in molecular subsets, such as that hormone negative DCIS (Basal and most HER2 subtypes) are more likely to be progressors compared to hormone positive DCIS (Supplemental Figures S5B, S5E, S5F), these results would be insufficient to predict progression to IBC, although this may be due in part to the increasingly small sample numbers in the molecular subclasses. This evidence concerns the gene ERBB2 and ductal breast carcinoma in situ.