BACKGROUND: Enhancer of zeste homolog 2 (EZH2), the catalytic subunit of the polycomb repressive complex 2, plays an important role in tumor development and progression by interacting with histone and non-histone proteins. EZH2 represents a putative therapeutic target and has been suggested as a prognostic marker in several cancer types.
MATERIAL AND METHODS: This study investigates the prognostic relevance of immunohistochemical EZH2 expression in head and neck squamous cell carcinoma. Tissue microarray sections with 667 cancers of oral cavity, oro- and hypopharynx and larynx were analyzed for EZH2 expression.
RESULTS: Nuclear EZH2 staining was recorded in 322 (81.8%) of 394 cases. Staining was weak in 33 (10.2%), moderate in 128 (39.6%), and strong in 103 (32.0%) cancers. The prevalence of EZH2 expression in tumors of the oral cavity and the orohypopharynx was higher as compared to cancers of the larynx (P = .0023). EZH2 expression was correlated to presence of lymph node metastasis (P = .0089) but was unrelated to histological grade, tumor stage, surgical margin, or distant metastasis. EZH2 expression had no impact on patient survival.
CONCLUSION: The high prevalence of EZH2 expression in head and neck squamous cell carcinoma stresses its capability as a therapeutic target.