FLT1 expression enhances tumor invasion via activation of placental growth factor (PlGF) and MAPK/metalloproteinase 9 (MMP9), MMP1, and 3 (36, 37), promotion of epithelial-mesenchymal transition (13, 38, 39) and recruitment of metastasis-associated macrophages (40). The gene discussed is MMP1; the disease is neoplasm.