Differential effect of BMI1 and EZH2 on INK4a/ARF locus and association with TP53 mutations. (a) Dotplot of INK4a/ARF (CDKN2A) expression versus BMI1 and EZH2 expression. INK4a/ARF expression is not found in tumours with high BMI1 mRNA, whereas it does occur in tumours with high EZH2 (red circle). (b) Distribution of patients with positive TP53 staining (mutated TP53) differs by categorised EZH2 and BMI1 levels. TP53 immunohistochemistry (IHC) data was obtained from 273 patients and the TP53 sequence was analysed in 204 tumours. The distribution of mutant TP53 shows a similar pattern (TP53 mutation). (c) Logistic regression analysis of TP53 IHC and sequence status on EZH2 and BMI1 levels. CI = confidence interval, OR = odds ratio.