PDGFRB and hepatocellular carcinoma: The upstream RTKs receptors of MAPKs play a critical role in the activation of signaling pathways, including EGFR, hepatocyte growth factor receptor (HGFR; c-MET), Vascular Endothelial Growth Factor receptor (VEGFR), platelet derived growth factor receptor (PDGFR), etc. In HCC, these receptors are also regulated by some microRNAs.