The mechanism of ECM reshaping by exosomal miRNAs . Exosomes secreted by the primary tumor cells are taken up by the receptor NFs, wherein the exosomal miRNAs (miR-155, miR-21, miR-124, etc.) target the proteins (SOCS1, PTEN, SPHK1, etc.) and activate the molecules (FGF2, bFGF, TGF-β, α-SMA, FAP, etc.). These exosomal miRNAs reshape the ECM by inducing the conversion of normal fibroblasts (NFs) into cancer-associated fibroblasts (CAFs).