Lineage plasticity enables low-ER luminal tumors to evolve and gain basal-like traits

Breast tumors expressing lower levels of Estrogen Receptor (ER) represent a distinct subset of breast cancer characterized by the emergence of basal-like characteristics within tumors that are traditionally considered luminal-like. Lineage tracing of these low-ER tumors in the MMTV-PyMT mouse mammary tumor model revealed that the basal-like tumor cells within these tumors arose from normal luminal epithelial cells, suggesting that luminal-to-basal plasticity is responsible for the evolution and emergence of basal-like characteristics within these tumors. This study aims to identify the potential drivers of this plasticity by using single-cell RNA sequencing to identify populations of lineage-restricted luminal cells and luminal-derived basal cells within the tumor, and comparing their gene expression profiles. Overall design: Single-cell RNA-sequencing of mouse MMTV-PyMT tumors labelled with GFP on the luminal epithelial lineage