After PDGF activates PDGFR, the receptor phosphorylates the downstream PI3K/AKT or RAS/MAPK signaling pathway and exerts its biological functions.[18] Abnormal activation of PI3K/AKT signaling pathway or MAPK pathway both are associated with poor prognosis and chemoresistance in malignant tumors.[19] While it is currently understood that PDGFC exerts its biological functions by activating downstream pathways via binding to PDGFR, the specific mechanisms by which PDGFC promotes tumor proliferation and metastasis are still under investigation. The gene discussed is PDGFRB; the disease is cancer.