Immunophenotypic analyses of DCIS and recurrences have shown that recurrence as DCIS and invasive carcinoma both have high ER status concordance (85 and 84%, respectively, and 85–95% overall) as well as high HER2 concordance (88 and 91%, 88–89.5% overall) (124, 126). This evidence concerns the gene ESR1 and ductal breast carcinoma in situ.