Concerning HCC, it has been confirmed that the platelet-derived growth factors (PDGF, including PDGFA, PDGFB, PDGFC, and PDGFD) participate in modulating the tumor development and chemoresistance by interacting with its receptor PDGFR and activating the downstream signaling pathway [34–36]. The gene discussed is PDGFD; the disease is hepatocellular carcinoma.