PDGFD and cancer: PDGF-D is frequently upregulated in various types of cancer and plays an important role in tumor progression, angiogenesis, and metastasis through multiple oncogenic pathways, including phosphatidylinositol 3-kinase/Akt, nuclear factor-κB (NF-κB), extracellular signal-regulated kinases, mitogen-activated protein kinases, and the Notch pathway [14, 15].