PDGFRB and neoplasm: Platelet-derived growth factors (PDGFs), an α-granule component secreted in an autocrine manner during platelet activation,443 are critical proangiogenic factors for tumor angiogenesis.443,444 The PDGF family contains four different monomeric polypeptide chains: PDGF-A, -B, -C, and -D, which form four homodimers through disulfide bonds (PDGF-AA, -BB, -CC, -DD) and a PDGF-AB heterodimer.443,445 The PDGF receptor (PDGFR) consists of RTKs PDGFRα and PDGFRβ.