Samples were divided into three groups: 13 normal prostate tissues, 11 prostate cancer tissues with Gleason score > 7 and 10 prostate cancer tissues with Gleason score ≤ 7. Enriched regions were defined via an Enrichment Score (ES)-based sliding window approach using RINGO software , then the binding sites were annotated to human genes using the ENSEMBL database. Importantly, we selected genes whose enrichment score was greater than 1.5 in the promoter regions. Among the 21,000 genes analyzed in human 2X400K, we calculated the average of H3K27me3 modifications among patients in each group. We identified an average of 386 genes with H3K27me3 marks in the promoter regions in healthy control group versus 545 genes in GS ≤ 7 and 748 genes in GS > 7 group. These results suggested that there are more extensive H3K27me3-enriched gene promoters in advanced disease than normal tissues.