KDR and cancer: Moreover, sVEGFR1-e15b, produced by exon 15b inclusion (Fig. 3b), features matrix-binding properties and is expressed in the placenta and vascular tissues, contributing to abnormal angiogenesis in cancers and ocular diseases.105 Functioning as decoy receptors, these isoforms regulate VEGF ligand distribution, limiting VEGFR2 activation and attenuating pro-angiogenic signaling.