PGE2-EP4 activation on tumor cells and TAMs increased the amount of VEGFC and VEGFD secreted from these cells and then stimulated LEC lymphangiogenesis.358 Tumor-derived PGE2 also directly acted on LECs to activate EP4 and VEGFR3 and ultimately induced lymphangiogenesis.359. The gene discussed is FLT4; the disease is neoplasm.