ESR1 and ductal breast carcinoma in situ: A new revised model of progression from in situ to invasive carcinoma has been proposed based on the molecular data.8 It suggests that the estrogen receptor (ER)-positive and ER-negative pathways of breast carcinogenesis are fundamentally distinct, and that lobular neoplasia, mostly LCIS has the possibility to progress to low-grade DCIS as well as to classical ILC in the ER-positive pathway.