This treatment also induced an irreversible replacement of the constitutive Tomato expression (red) by the expression of GFP only in K5+ basal keratinocytes and K5+ epidermal stem cells (Fig 2A), allowing tracing of epidermal stem cells and their progeny (transient‐amplifying and differentiated keratinocytes) during psoriasis progression. This evidence concerns the gene KRT5 and psoriasis.