The finding that the CD34+ cell subset is recruited by PT45-CM, along with the higher tumor-derived levels of VEGF-A and Angio-1 that play prominent roles in the vascularization process, prompted us to investigate whether tumor cells might cause differentiation of these CD34+ progenitor cells along the myeloid lineage to be switched toward the endothelial cell lineage. This evidence concerns the gene CD34 and neoplasm.