FLT-1 (fms-related tyrosine kinase 1) is an endogenous inhibitor of vascular endothelial growth factor, which is involved in cardiovascular remodeling and atherosclerosis development. It potently inhibits angiogenesis by binding extracellularly to VEGF (vascular endothelial growth factor). FLT-1 is expressed on tumor cells and is implicated in tumor growth and progression. It is overexpressed in primary tumors and nodal metastasis. FLT-1 regulates monocyte migration, recruits endothelial cell progenitors, increases the adhesive properties of natural killer cells and induces growth factors. It is observed in many diseases with endothelial dysfunction, including pre-eclampsia and diabetic retinopathy, but whether it contributes to endothelial injury in IgAN requires further exploration.