Shear stress and coordinated interactions between endothelial growth factors (VEGF, PDGF-B, ANG2, ANG1, bFGF, ephrin-B2, and TGF-beta superfamily), intracellular signaling molecules (NOTCH1 and COUP-TFII), and intercellular connections (VCAM1) contribute to tumor angiogenesis, which may activate the PI3K/Akt/mTOR pathway in cancer cells. The gene discussed is PIK3CA; the disease is neoplasm.