In our model, KS-associated angiogenic endothelial heterogeneity was noticed as mECKnull.rK133 tumors were found to express markers implicated in KS pathogenesis such as the vascular marker, VEGF-R2, and podoplanin, a lymphatic endothelial marker [57], [58]. This evidence concerns the gene KDR and Kaposi's sarcoma.