PLGF (also called Placenta Growth Factor, PIGF, PGF) is an angiogenic factor that belongs to the cysteine-knot superfamily of growth factors. PLGF is expressed in placental tissues, colon and mammary carcinomas. It signals throμgh the VEGFR-1/FLT1 receptor and stimulates endothelial cell proliferation and migration. Recombinant mouse PLGF is a disulfide-linked homodimer containing two 142 amino acid polypeptide chains.