CCNB1 and pachyonychia congenita: In an analysis of the association between Cyclin B1 expression and the prognosis of 241 patients with PC, Zhou et al. showed that patients with tumors expressing high levels of Cyclin B1 (grade 2, > 30% positive immunostaining) had a poorer median overall survival than those with low-level expression of Cyclin B1 (12.4 months versus 22.8 months, p = 0.01) [48].