ERBB2 and neoplasm: To further examine tumor microenvironment–specific transcriptional reprogramming in TNBC, we performed bi-volcano analyses comparing TNBC with HER2+ and ER+ subtypes across several major cell lineages, including T cells, cancer-associated fibroblasts (CAFs), myeloid cells, perivascular-like (PVL) cells, and endothelial cells.