VDR and Hand-foot syndrome: In this study, the CRISPR/Cas9 system was used to generate a modified cell line to investigate the functions of VDR. In particular, dermal papilla (DP) cells play a central regulatory role in the development of HFs (Jahoda, Reynolds & Oliver, 1993; Driskell et al., 2011; Aoi et al., 2012a; Aoi et al., 2012b).