ITGB4 and cancer: Stromal crosstalk was exemplified by Wang et al., who reported that cancer-associated fibroblast (CAF) exosomes depleted of miR-34c-5p enhance NOTCH1-mediated stemness and chemoresistance [23], while Wu et al. identified a 12-miRNA CAF signature predicted to remodel extracellular-matrix hubs FN1 and ITGβ4 [24].