Supplementary Material for: EZH2 Expression in Retinoblastoma: a Potential Therapeutic Target

Introduction: The enhancer of zeste homolog 2 (EZH2) is a member of the polycomb repressive complex 2 (PRC2) and is important in cell cycle regulation. Increased expression of EZH2 has been reported in retinoblastoma (RB). The aim of the study was to determine EZH2 expression and compare this with clinicopathological parameters in RB and to assess its relationship with tumor cell proliferation. Methods: Ninety-nine retrospective cases of enucleated RB were included in the present study. Expression of EZH2 and the marker of cell proliferation, Ki67, were investigated by immunohistochemistry. Results: Among the 99 cases of retinoblastoma in this study, EZH2 was found highly expressed (positive expression rate≥70%) in 92 cases. EZH2 was expressed in tumor cells but absent in normal retinal tissues. The expression of EZH2 was positively linked to Ki67 expression (r=0.65, P<0.001). Discussion/Conclusion: Elevated EZH2 expression was found in most RB cases, indicating that EZH2 could be a potential therapeutic target for RB.