Placenta growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family of growth factors. As a result of alternative splicing, at least two PlGF mRNAs encoding monomeric PlGF precursors containing 149 and 170 amino acid residues have been described. The expression of PlGF is not widespread but has been detected in human umbilical vein endothelial cells, placenta, choriocarcinoma cell lines, and in renal cell carcinoma associated with angiogenesis. The PlGF proteins bind with high-affinity to VEGF R1/Flt-1 but not to VEGF R2/Flk-1.

Strain specific analysis of PGF mRNA expression in wild-type C57BL/6 mice and B-hPGF mice by RT-PCR. Thymus gland RNA were isolated from wild-type C57BL/6 mice (+/+) and homozygous B-hPGF mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human PGF primers. Mouse Pgf mRNA was detectable only in wild-type C57BL/6 mice. Human PGF mRNA was detectable only in homozygous B-hPGF mice but not in wild-type mice.