PIK3CA and cancer: Activated PDGF/PDGFR axis continue to activate downstream signaling pathways, such as PI3K/AKT/mTOR pathway, RAS/MAPK/ERK pathway, and JAK/STAT3 pathway, which lead to proliferation, survival, and invasion of cancer cells.16,17 Specificity of interactions between PDGF ligands and PDGFR receptors have been clarified: PDGFRA homodimer are activated by PDGF-AA, -AB, and -CC, PDGFRB homodimer are activated by PDGF-BB and -DD, and PDGFRA/PDGFRB heterodimer are only activated by PDGF-AB.16,17 Therefore, PDGFRA is the only identified receptor to mediatePDGFA function in GBM.