ESR1 and ductal breast carcinoma in situ: Background. To our knowledge, the hormone receptorstatus of noncontiguous ductal carcinoma in situ (DCIS) occurringconcurrently in ER/PgR-negative invasive cancer has not been studied.The current study was undertaken to investigate the ER/PgR receptorstatus of DCIS of the breast in patients with ER/PgR-negative invasivebreast cancer.