FLT1 and neoplasm: Deposition of the ECM in the lung can increase adhesion ability of VLA-4+/VEGFR1+ hematopoietic progenitor cells (HPCs) in the lungs to stimulate the development of a pre-metastasis into a colonization site for endothelial progenitor cells (EPCs) and disseminated tumor cells (DTCs) [50].