Therefore, more studies are needed to explore the relationship between NOX4 and other oncogenes, such as CDKN2A and SMAD4. If we could prove that a variety of genetic mutations play carcinogenic role in PC are associated with NOX4, then NOX4 would become the greatest target of PC as it could be applied to patients carrying different genetic mutations. Here, SMAD4 is linked to pachyonychia congenita.