Description
Soluble VEGF-R1 (sFLT-1) is a naturally occurring endogenous form of the VEGF-R1 and was originally found in the supernatant of Human vascular endothelial cells. It is generated by differential splicing of the flt-1 gene. In vitro sVEGF-R1 is used to inhibit VEGF-A mediated signals in endothelial cells and in vivo it can be used to block physiological angiogenesis in several organs, e.g. in the ovary or in bones. Tumor cells transfected with the flt-1 gene are growth restricted in vivo because of the limitation in developing tumor blood vessels via VEGF-A signalling. Very recent studies have shown that this molecule is present endogenously at ng/ml concentrations in biologicals fluids of normal Human subjects or in the conditioned media of FLT-1 positive cell types