The hyperkeratosis resulted, at least in part, from Nrf2-mediated upregulation of secretory leukocyte protease inhibitor (Slpi) (Schäfer et al., 2014), an inhibitor of the proteases Klk7 and Ela2 (Bonnart et al., 2010; Franzke et al., 1996; Schäfer et al., 2014). Here, SLPI is linked to Hyperkeratosis.