While podoplanin is absent from normal interfollicular epidermis, it is upregulated in basal epidermal keratinocytes and dermal fibroblast-like cells under hyperproliferative conditions, such as wound healing [88,89,91], psoriasis [89,92], or upon a pro-inflammatory stimulus with the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) [88,93]. This evidence concerns the gene PDPN and psoriasis.