The abnormal expression and activation of the transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) and its major negative regulator Kelch-like ECH-associated protein 1 (Keap1) have been observed at different stages of PC and correlated with its initiation, progression, metastasis, and chemoresistance (as shown in Fig. 1) [9, 10]. This evidence concerns the gene KEAP1 and pachyonychia congenita.