ERBB2 and breast cancer: We also observed significant differences in the stromal compartment: Lum A BC contained more ECT5 (composed of IL-iCAF, Adipo-EC, contractile-CAP) and ECT9 (ECM-myCAF, TGFβ-myCAF, Ag-CAP) compared to Lum B, HER2 and Basal-like TN BC.