CAFs secrete carboxypeptidase E, PDGFD, EFEMP1 (EGF-containing fibulin ECM protein 1), and IBP5 and IBP7 (insulin-like growth factor binding proteins 5 and 7), which exert their effects on tumor cells through IGF and PDGFR and activate cancer stem cell proliferation [119]. Here, IGFBP5 is linked to cancer.