ESR1 and triple-negative breast carcinoma: While the previous study identified the subsets characterized by ACKR1, LYVE1, CXCL12 and RGS5 (right, Figure 6D), M138 is a unique subset of capillary endothelial cells (ECs) characterized CA4 expressions (Figure 6E)[37, 38], and is present in ER+, Her2+ and triple-negative breast cancer (TNBC) subtypes with enrichment of cells from TNBC, compared to the pool of all ECs (Figure 6F; FET p-value = 8.71E-5, EFC = 1.62).