ESR1 and breast cancer: In summary, luminal epithelial cells with low ESR1/PGR/HER2 were mainly enriched in tumor zone, and they preferentially expressed some pro-proliferation genes and EMT markers, while proliferative luminal B cells were mainly enriched in the interface zone, suggesting that breast tissues of breast cancer patients should not be simply divided into tumor or normal zone, and that the interface zone with a special microenvironment should not be ignored.