Surprisingly, SCT cells grew more slowly in p16/p21-DKO mice than in sex- and age-matched WT mice (Fig. 2a, b; Supplementary Fig. 2), suggesting that p16Ink4a and p21Cip1/Waf1 have a tumour-promoting role, at least in the present experimental setting. Here, CDKN1A is linked to neoplasm.