The concept behind generating ValloVax from placental endothelial cells was the involvement of these cells in not only creation of the vascular infrastructure supporting the maternal-fetal interphase, but also the unique immunological environment in the placenta, which resembles tumor vasculature from the perspective of both expressing FasL [35, 36], IL-10 [37, 38], TGF-beta [39], and other immune modulatory enzymes such as indolamine 2,3 deoxygenase [40]. This evidence concerns the gene FASLG and neoplasm.