MKI67 and pachyonychia congenita: In terms of prognosis, Kameyama et al. reported elevated Ki-67 levels in PC patients with a poor prognosis [25], and Iihara et al. suggested that Ki-67 of 5% or above indicates a poor prognosis, and in particular, that recurrence develops early after surgery when Ki-67 is 10% or above [26].