NOTCH1 and pachyonychia congenita: To investigate the involvement of the Notch1 signaling pathway in the oncogenic role of PSMD7 in PC, the plasmid for Notch1 overexpression was first transfected into PSMD7 knockdown cells, and subsequently, HES1, Notch1, and PSMD7 protein expression was analysed by western blotting.