KRT15 and ductal breast carcinoma in situ: However, we identified a small triple positive (ERBB2 + /ESR1 + /PGR + (HER2 + /ER + /PR +)) DCIS region located in proximity to adipocytes which consisted of a predominantly DCIS #2 tumor epithelium without a KRT15+ myoepithelial cell layer (Fig. 5b–d).