FLT1 and neoplasm: The enhanced expression of VEGF leads to increased angiogenesis either through the recruitment of endothelial progenitor cells from bone marrow cells to the tumor vasculature or through autocrine loops in the tumor cell where VEGF binds to VEGFR-1 or VEGFR-2 on tumor cells [70], resulting in the expression of downstream proteins that enhance the survival, proliferation, and vascular permeability of the tumor [71].