EZH2 is overexpressed in BRCA1-deficient human breast tumors. (a) The mean (± standard error of the mean) log10 ratio of EZH2 expression in human breast cancer samples  is -0.15 (± 0.041; >five-year survival, good prognosis), 0.028 (± 0.046; <five-year survival, poor prognosis) and 0.177 (± 0.047; BRCA1-deficient). EZH2 expression is significantly different between the three groups (* Kruskall-Wallis test). (b) Immunohistochemistry for EZH2 in human breast tumor tissues (scale bar represents 100 μm). Two examples are shown of individual tumors for each subtype, representative of a total of six tumors analysed per subtype. (c) Quantification of EZH2 immunohistochemistry shown in b (* Wilcoxon exact test).