PLGF derived from SCLC cell lines triggers the activation of vascular endothelial growth factor (VEGF) receptor-1-Rho-extracellular regulated protein kinase 1/2 signaling axis, which promotes the disassembly of tight junctions in brain endothelial cells and tumor cells transmigration in vitro [37]. Here, PGF is linked to small cell lung carcinoma.