Very few studies have previously shown an association between promoter hypermethylation and survival of patients with PC (Richiardi et al., 2009; Torres‐Ferreira et al., 2017); however, to solidly establish the association between ZNF660 promoter methylation levels and PC aggressiveness, larger patient cohorts with longer follow‐up and more OS/CSS events should be analyzed. Here, ZNF660 is linked to pachyonychia congenita.