CCND1 and papilloma: Although the most impressive immunofluorescent evidence for increased pAKT signalling occurred in the hair-bearing skin of the outer lip, overall there is evidence of altered proliferation (increased EdU and Ki-67 staining) with cyclin D1 expression in the squamous epithelium of the wet oral mucosa, which is the cell type giving rise to the hyperplasia–papilloma–dysplasia–carcinoma sequence in this model.