The other tumor suppressor gene characterized here was ING3. This inhibitor of growth-family protein was initially identified as a tumor suppressor with altered regulation in a variety of cancer types, including in colorectal cancer cells [24, 25]. ING is, however, a protein involved in chromatin remodeling. In fact, ING3 acts as a reader of epigenetic code through specific recognition of H3K4me3 and can affect HAT and HDAC activity by serving as members of the Sin3A, Tip60 or Moz/Morf HAT complexes . Our results showed the epigenetic regulation of ING3 via H3K27me3 in prostate cancer suggesting putative tumor suppressor gene silencing by histone methylation in prostate cancer. These data suggest that the ING3 locus may locate in bivalent domains marked by both H3K27me3 and H3K4me3 and that ING3 may thus play a critical role in cancer development.