A study by Kaplan et al. shows that bone marrow-derived hematopoietic progenitor cells that express vascular endothelial growth factor receptor 1 (VEGFR1) are attracted by deposits of fibronectin secreted by resident fibroblasts just days after tumor implantation, establishing a pre-metastatic niche for the arrival of tumor cells [115]. The gene discussed is FLT1; the disease is neoplasm.