Enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) is a gene that encodes a histone methyltransferase protein. EZH2 is a member of the polycomb-group family. Members of this family suppress transcription of genes and are involved in embryonic development and cellular differentiation (Gene 2014; Genetics Home Reference 2014). EZH2 mutations have been observed in myelodysplastic syndromes, lymphoma, colorectal cancer, and endometrial cancer. In MDS, these mutations often involve deletions or translocations which are believed to be associated with loss of function. Paradoxically, mutations in lymphomas and epithelial neoplasms are thought to involve gain of function.