Enzymes from this family, especially furin and PACE4, have been investigated regarding their implications in tumor progression, since they are involved in the processing and activation of various protein precursors that have been associated with cancer progression, including tumor growth factor beta (TGFβ), matrix metalloproteinases (MMP), and insulin-like growth factor receptors (IGF1 R) [7]. Here, PCSK6 is linked to cancer.