In one of the most significant papers on prostate cancer recently, a tumor progression array was used to show that the expression of a novel protein, EZH2, correlated with aggressiveness of disease.31 (3) In prognostic (patient outcome) arrays, correlation of tissue microarray-derived data with clinical follow-up, to assess prognosis or patient outcome, is of significant interest to clinicians and their patients.4 An example is the study of the expression of the EZH2 protein in prostatic cancer. This evidence concerns the gene EZH2 and prostate carcinoma.