LCs are present at a rate of about 2–5% in normal epidermis but increase in AD: 13–16% of KCs isolated from AD patients in vitro, and nearly 30% in vivo, were positively stained with a proliferation marker, ki67 (Czernielewski and Demarchez, 1987; Chorro et al., 2009; Toriyama et al., 2020). The gene discussed is MKI67; the disease is Alzheimer disease.