COL1A1 and neoplasm: With the tumor progression, the FAP+TGF-β+ CAFs cluster and FAP+α-SMA+ CAFs were specifically enriched in advanced tumors, with high expression of the characteristic factors FAP, TGF-β, PDPN, activation related genes COL1A1, COL3A1 and BGN and some unique tumor-associated collagens such as collagens V, VIII, and XII, which are associated with tumor growth (16, 19, 27, 30).