For instance, α-SMA is present in vascular smooth muscle cells, fibroblast-specific protein 1 in macrophages and some cancer cells, FAP in certain tumor-associated macrophages (TAMs), and PDGFRα and PDGFRβ in vascular endothelial cells and multiple tumors.31, 32, 33 The heterogeneity of CAFs, both in their markers and functions, emphasizes the need for further research to identify specific biomarkers and functional subsets.34 The gene discussed is PDGFRB; the disease is cancer.