NRG1 and breast cancer: We validated the correlation of these genes (i.e. ITGB2, EPHB1 and HAS2) with NRG1 in a second set of primary CAFs from an independent source (https://breastcancernow.org/breast-cancer-research/breast-cancer-now-tissue-bank) (Fig. 5B), and we explored their expression in LCM stroma datasets from breast cancer patients (Fig. 5C).