In PC, fibronectin production is related to the activation of the NF-κB pathway: Jagadeeshan and coworkers demonstrated that p21-activated kinase 1, a serine/threonine kinase significantly upregulated in PC as compared to normal tissue, stimulates fibronectin production by promoting the direct NF-κB binding to fibronectin promoter [181]. The gene discussed is PAK1; the disease is pachyonychia congenita.