Furin and other PC family members (furin/PCs) activate a number of proteins, including matrix metalloproteases (MMPs).163 MMP are specifically overexpressed in many metastatic cancers.23,24 The metastatic cells frequently secrete MMP, which is able to degrade the extracellular matrix and help these cells to metastasize. This evidence concerns the gene FURIN and metastatic malignant neoplasm.