Defining breast epithelial cell types in the single-cell era

Single-cell studies on breast tissue have contributed to a change in our understanding of breast epithelial diversity that has, in turn, precipitated a lack of consensus on breast cell types. The confusion surrounding this issue highlights a possible challenge for advancing breast atlas efforts. In this perspective, we present our consensus on the identities, properties, and naming conventions for breast epithelial cell types and propose goals for future atlas endeavors. Our proposals and their underlying thought processes aim to catalyze the adoption of a shared model for this tissue and to serve as guidance for other investigators facing similar challenges.