ERBB2 and neoplasm: To characterize the transcriptomic heterogeneity of the vasculature and other cell types in human breast (cancer) tissue, we collected tumor tissue and matched (from the same patient) peri-tumoral (non-malignant, as far away from the primary tumor as possible) tissue from 9 early stage, treatment-naïve hormone receptor-positive, HER2-negative BC patients (Fig. 1a) (for patient information and molecular characteristics, see Fig. 1b and Supplementary Data 1).