EZH2 and cancer: Several studies reveal EZH2 target genes pre-marked by PRC2-mediated H3K27me3 in normal cells as strongly correlated with genes becoming aberrantly hypermethylated in cancer cells, suggesting genes pre-marked H3K27me3 by PRC2 in normal development later become densely DNA-hypermethylated in the presence of oncogenic cues like abnormally elevated EZH2 expression [45-47].