This reduction of ER phenotypic divergence in synchronous DCIS samples was replicated in the within-sample measures (p = 0.01) and mimicked by CA9 (p = 0.01) (Fig. 3C, Supplementary Fig. S4, Pairwise Mann–Whitney U tests, unadjusted p values). This evidence concerns the gene CA9 and ductal breast carcinoma in situ.