Fig. 1

The “double face” of cancer-associated fibroblasts (CAFs). CAF subsets identified by different biomarkers play distinct roles in tumor microenvironment. a, several studies have shown that CAFs expressing α-SMA or S100A4, which are considered tumorigenic previously, are also potentially anti-tumor. Identification of myCAFs and iCAFs among α-SMA⁺ CAFs may represent an aspect of CAF heterogeneity, which is believed that two subsets can convert into each other. b, most biomarkers represent tumor-promoting CAFs including traditional CAF biomarkers (FAP, PDGFR, Vimentin, PDPN and CD70) as well as some newly identified markers (CD49e, CD10/GRP77 and MHCII/CD74). c, CD146⁺ CAFs, CAV1^high CAFs and PDGFRα⁺Saa3⁻ have been identified as tumor-suppressive CAF subsets