ERBB2 and ductal breast carcinoma in situ: These include: some HER2-positive DCIS lose HER2 expression when they progress to invasive cancers[19]; invasive carcinomas may arise more frequently from HER2-negative DCIS than from HER2-positive DCIS; there is a bias in mammographically screened populations toward the detection of DCIS lesions that are HER2-positive since these lesions are more frequently associated with comedo necrosis and, in turn, suspicious mammographic microcalcifications that prompt biopsy than non-high-grade DCIS lesions.