PDPN and neoplasm: Phenotypically and functionally different CAF subtypes based on cell-surface markers such as podoplanin (PDPN), α-smooth muscle actin (αSMA), fibroblast-activated protein (FAP), fibroblast-specific protein-1 (FSP-1/S100A4), THY1 (also known as CD90), and platelet-derived growth factor receptor-α, and β (PDGFRα and PDGFRβ) have been associated with different tumour types, stages and patient survival (107–111).