VEGFA (vascular endothelial growth factor A) is aglycosylated mitogen that acts on endothelial cells, where it activates cellular proliferation, angiogenesis and migration. It is vital for organ remodeling, vasculogenesis, the regulation of neuronal vascular supply, and endothelial cell differentiation, and it is the primary activator of blood vessel growth. VEGFA is involved in activating PI3K-Akt, MEK-ERK and other downstream signaling pathways, and as an actor in angiogenesis it promotes an increase in microvessel density when overexpressed in cancer. In immunohistochemistry, VEGFA is a marker for tumorigenesis, specifically angiogenesis and proliferation, and is regularly overexpressed in breast and many other cancers. It has cytoplasmic expression in all normal tissues. References: Oncology 2010 Apr; 4; 15-34, PMID: 20567632; Nucleic Acids Research 2016 Jan; 44.D1; D733-745, PMID: 26553804; Development. 2012 Apr;139(8):1371-80, PMID: 22434866;