SUZ12 (suppressor of zeste 12) is the human homolog of the drosophila SUZ12 gene. SUZ12 is a Polycomb group (PcG) protein and a component of the PRC2/EED-EZH2 complex, which methylates 'Lys-9' and 'Lys-27' of histone H3, leading to transcriptional repression of the affected target gene. A chromosomal aberration, t(7;17)(p15;q21), involving SUZ12 and JAZF1 may be a cause of endometrial stromal tumors. The translocation generates the JAZF1-SUZ12 oncogene consisting of the N-terminus part of JAZF1 and the C-terminus part of SUZ12. It is frequently found in all cases of endometrial stromal tumors, except in endometrial stromal sarcomas, where it is rarer [taken from the Universal Protein Resource (UniProt) www.uniprot.org/uniprot/Q15022].