PDPN and neoplasm: Fibroblast activation is triggered primarily by the secretion of potent factors derived from epithelial/tumor cells such as TGF‐β, PDGF, and basic fibroblast growth factor (bFGF), resulting in increased proliferation, increased contractility, and expression of activation markers such as αSMA, PDGFRα/β, fibroblast activation protein (FAP), podoplanin (PDPN), and desmin.1, 50, 51