Methylation of HAAO serves as a valuable prognostic marker in ovarian cancer (OC) and prostate cancer (PC) (Huang et al., 2009; Litovkin et al., 2014; Li Y. et al., 2021), and loss of HAAO promotes cancer cells resistant to ferroptosis (Liu et al., 2023). This evidence concerns the gene HAAO and pachyonychia congenita.