they were found to be either ( a ) basally positioned keratinocytes preferentially occupying sites within units of epithelial structure that correspond to those expected for epithelial stem cells , or ( b ) nonkeratinocytes of the langerhans cell type which lie suprabasally except in the epidermis where they are present in low numbers and occupy a similar position to label-retaining keratinocytes .
C0022567
sites
C0014520
epidermis