FLT1 (fms-related tyrosine kinase 1) or VEGFR (vascular endothelial growth factor receptor) is implicated in angiogenesis in tumors, which plays a key role in tumorigenesis, invasion and metastasis of tumors, especially the malignant ones. In human circulation, angiogenesis is balanced by soluble FLT1 (sFLT1) and VEGF. An imbalance leads to multiple conditions such as pre-eclampsia. sFLT1 plays an essential role in the angiogenesis of placenta. An overexpression of this protein in placenta is associated with prenatal arsenic exposure and thus, reduced birth weight.
