Vascular endothelial growth factor receptor 1 is a protein that in humans is encoded by the FLT1 gene. Oncogene FLT belongs to the src gene family and is related to oncogene ROS (MIM 165020). Like other members of this family, it shows tyrosine protein kinase activity that is important for the control of cell proliferation and differentiation. FLT1 has been shown to interact with PLCG1 and vascular endothelial growth factor B (VEGF-B).