Table 4.

Summary of markers for identification of CAFs

Potential CAF markers	Biochemical and molecular characteristics
α-SMA (alpha-smooth muscle actin)	Important role in cell motility, structure and integrity 29. prognostic significance in breast and colon cancer 35, 36.
FAP-α (fibroblast activation protein α)	Type II integral membrane protein from the membrane-bound serine protease family 29. Regulation of epithelial-mesenchymal transition (EMT) 37.
S100A4 (S100 calcium binding protein A4) /FSP1 (fibroblast-specific protein 1)	Involved in angiogenesis, invasion, and metastatic colonization 38. Common fibroblast marker but considered to be a marker for quiescent fibroblasts rather than CAFs 29.
PDGFR (platelet-derived growth factor receptor)-α	Widely expressed over the larger fibroblast population. Mutated in approximately 10% of gastrointestinal stromal tumor patients 29.
PDGFR-β	Tyrosine kinase receptors on the surface of fibroblasts, astrocytes, neuroprogenitors and pericytes 29. Enhance EMT, cancer cell stemness, and angiogenesis 30.
Collagen type I	Expressed in myofibroblast subtype 40.
NG2 (nerve glial antigen 2)	Enhance tumor cell invasion and metastasis through integrin activation 41. Also positive in by numerous other cells, such as myeloid and T-cells 27.
Tenascin-C	Member of the extracellular matrix. Linked to tumor invasiveness and metastatic progression 20.
Twist1	Basic helix-loop-helix transcription factor. Important inducer of EMT 21.