Moreover, MMP14 is overexpressed in the epithelium in invasive PC (Iacobuzio-Donahue et al., 2002; Shields et al., 2012), and MMP14, as an endopeptidase, can degrade various components of the ECM such as collagen, which possibly leads to metastasis of tumors (Golubkov et al., 2010). This evidence concerns the gene MMP14 and pachyonychia congenita.