Ezh2 expression is elevated in BRCA1-deficient primary mouse mammary tumors. (a) mRNA levels of Ezh2 in BRCA1-deficient (K 14cre; B rca 1F/F; p 53F/F(KB1P)) and BRCA1-proficient (K 14cre;Brca1w.t/w.t; p 53F/F(KP)) mammary tumors analyzed by microarray analysis. The mean (± standard error of the mean) log2 ratio of Ezh2 expression in 21 KP tumors is -0.036 (± 0.067) and 0.497 (± 0.054) in 32 KB1P tumors. The Ezh2 expression is significantly higher in KB1P tumors compared with KP tumors (*Wilcoxon exact test). (b) EZH2 protein levels in two independent primary KB1P and in two independent primary KP tumors detected by immunohistochemistry (scale bar represents 100 μm), representative of a total of four tumors analysed for each genotype. (c) Quantification of EZH2 immunohistochemistry shown in b (* Wilcoxon exact test).