ESR1 and ductal breast carcinoma in situ: In the large, diverse, multi-center population-based cohort study reported here, we examined the associations between several clinicopathologic factors (method of DCIS detection, tumor size, DCIS margins status, DCIS grade, comedonecrosis, and ER, PR, and HER2 receptor status) and risk of subsequent invasive breast cancer (IBC) in women with DCIS.