Table 1.

List of potential CAF biomarkers in lung cancer

CAF marker	Bio function in tumor microenvironment	Expressing cell	Ref.
α-SMA	Promoting tumorigenesis, ECM remodeling, proliferation, drug resistance, immune tolerance through T and NK, DC cells exhaustion, Th2 responses, M2 and Treg recruitment	Vascular, muscular cells pericytes, fibroblasts	[25-27]
FAP	Promoting tumorigenesis, tumor invasion, ECM remodeling, immune tolerance, Th2 responses, M2 and Treg recruitment	Rarely expressed in normal tissues, epithelial tumor cells, M2 macrophages, tumor cells, tumor-promoting mesenchymal stromal cells, fibroblastic stromal cells	[27-30]
FSP1	ECM remodeling, tumor development, metastasis through VEGF-A and TNC-C, immune tolerance through M2 polarization recruitment	Fibroblasts, epithelial and endothelial cells	[31]
PDPN	tumor development, immune tolerance through T cell anergy, M2 polarization, and Treg recruitment	Endothelial cells	[32,33]
Collagen	ECM remodeling, angiogenesis, metastasis, immune suppression through M2 recruitment	Fibroblasts, tumor cells, endothelial cells	[34-36]
Vimentin	EMT mediated metastasis, tumorigenesis, and tumor development	Fibroblasts, mesenchymal cells	[37,38]
ITGA11	EMT, tumor progression	Mesenchymal cells	[39-41]
PDGFRα/β	Tumor development, immune evasion via T cell exhaustion and M2 polarization, angiogenesis	Fibroblasts, vascular smooth muscle cells, pericytes	[42,43]
CD10/GPR77	Inflammatory signaling, supporting CSC survival, promoting tumorigenesis, chemoresistance	Bone marrow mesenchymal stem cells, pre-B lymphocytes	[44,45]
TNC	ECM remodeling, EMT-mediated metastasis, angiogenesis and immunomodulation, tumor development	Fibroblasts, tumor cells, endothelial cells	[46-48]
Periostin	Tumor proliferation, metastasis	Fibroblasts, tumor cells, mesenchymal stem cells	[49,50]
Caveolin-1	ECM remodeling and desmoplastic reaction, cancer cell migration, and invasion	Adipocytes, endothelial cells, epithelial cells, pneumocytes, and fibroblasts	[51,52]

CAF: Cancer-associated fibroblast; α-SMA: alpha-smooth muscle actin; ECM: extracellular matrix; NK: natural killer; DC: dendritic cell; Th: T helper; M2: macrophage; Treg: T regulatory; FAP: fibroblast activating protein; FSP: fibroblast-specific protein; VEGF: vascular endothelial growth factor; TNC: tenascin; PDPN: podoplanin; EMT: epithelial-mesenchymal transition; ITGA11: α11β1 integrin; PDGFRα/β: platelet-derived growth factor receptor α/β; GPR: G-protein coupled receptor; CSC: cancer stem cell.