CHUK and papilloma: The tumorigenesis assays in Tg.AC mice showed that tumors from WT-TgAC animals were benign papillomas (Figure 4G, H), while tumors from K5-IKKα-TgAC mice showed areas of focal invasion, i.e., microinvasive infiltration, indicating a higher degree of malignant progression (Figure 4I, J).