PDGFRB and esophageal squamous cell carcinoma: We chose SMA, FSP-1, FAP, PDGFRα, and PDGFRβ as CAF markers based on previous studies.[1], [2], [4] This is the first study to investigate the expression and significance of SMA, FSP-1, FAP, PDGFRα, and PDGFRβ in ESCC as far as we know.