To test whether CYLD regulates carcinogen-induced tumour formation in other epithelia, we generated mice expressing the catalytically inactive CYLDΔ932 mutant in epidermal keratinocytes (CYLDΔ932epi) by crossing CYLDΔ932FL mice with K14-Cre transgenics (Supplementary Fig. 1e,f). The gene discussed is CYLD; the disease is neoplasm.