In control mice, Keratin 14 immunostaining showed keratin 14-positive cells confined to the basal layer of the epidermis with clear demarcation of dermis and epidermis, whereas in Rac1-EKO mice keratin 14 was expressed throughout the tumor and showed no clear demarcation of dermis and epidermis in certain areas (Figure 8c). This evidence concerns the gene KRT14 and neoplasm.