They observed β-galactosidase-positive (β-gal+) and green fluorescent protein-positive (GFP+) BMDCs colonized at tumor-specific pre-metastatic sites before the arrival of tumor cells using an in vivo imaging system (IVIS) and further demonstrated that BM-derived VEGFR1+ HPCs play a dominant role in forming pre-metastatic niches for tumor metastasis (Sahoo et al. 2018). This evidence concerns the gene FLT1 and neoplasm.