CNAs such as gain of CCND1 (on 11q) and ZNF217 (on 20q) genes, as well as copy number changes on 17q and 5q, were more evident in DCIS with clonal recurrences than in non‐recurrence cases (Figure 4C and supplementary material, Figures S14 and S15). Here, ZNF217 is linked to ductal breast carcinoma in situ.