FLT1 and neoplasm: Tumor-secreted factors regulate the expression of molecules such as S100A8, S100A9, LOX, fibronectin, MMP-9, MMP-217 that promote the recruitment of specific bone marrow-derived cells (VEGFR1+, CD11b+, CD34+), myeloid cells (CD11b+) as well as differentiated innate and adaptive immune cells17,18.