In particular, furin overexpression has been linked to aggressive metastatic tumors [18] presumably by activating cancer-promoting factors which include vascular endothelial growth factors (VEGF-C and D) [19], [20], transforming growth factor β (TGF-β) [21], insulin-like growth factor 1 receptor (IGF-R1) [22], bone morphogenic protein 4 (BMP-4) [23] membrane type 1 matrix metalloproteinase (MMP-1) [24] and several adamalysin metalloproteinases [25] as well as integrins [26]; or by inactivating tumor suppressors like Semaphorin-3B [27]. Here, FURIN is linked to cancer.