Because the expression levels of TIE-2 and VEGFR-1 controlled (Fig. 2) and mirrored (Fig. 1B) TEM pro-angiogenic activity, we assigned to TIE-2 and VEGFR-1 nodes a fixed polarity of either both over-expressed or down-modulated for highly pro-angiogenic (i.e. tumor TEM) or weakly pro-angiogenic (i.e. blood TEM) steady states respectively. This evidence concerns the gene FLT1 and neoplasm.