EZH2 Expression Correlates With T-Cell Infiltration in Oral Leukoplakia and Predicts Cancer Transformation.

BACKGROUND/AIM: The EZH2 complex is involved in cellular proliferation and modulates the immune response in cancer. Less is known about the importance of EZH2 in precancerous lesions such as oral leukoplakia (OL). The aim of the study was to explore the association between EZH2 expression, immune activation, and cancer transformation in OL. PATIENTS AND METHODS: Analyses were retrospectively performed on nine OL cases that had undergone transformation to oral squamous cell carcinoma (OSCC; OL-ca) and nine that had not undergone transformation (OL-non). EZH2-expressing cells, CD3+ and CD8+ T cells, and CD1a+ Langerhans cells were visualized with immunohistofluorescence and counted. RESULTS: A moderate positive correlation between CD3- and EZH2-expressing and CD8- and EZH2-expressing cells in the epithelium was found (r=0.57, p=0.01; r=0.59, p=0.01). The number of EZH2-expressing cells in the epithelium of OL-ca was significantly higher compared to OL-non (p=0.0002). Cancer-free survival rates differed significantly between patients with EZH2high compared to EZH2low expression (p=0.001). EZH2high expression in OL epithelium was associated with a 13-fold higher risk for developing OSCC (HR=12.8). CONCLUSION: EZH2 expression in oral epithelium predicts OSCC transformation of OL and correlates with the level of T-cell infiltration.

Potentially Malignant Oral Disorders and Cancer Transformation.

Cancer in the oral cavity is often preceded by precursor lesions. Nine oral mucosal disorders are known to have an increased risk of malignant transformation. The etiology varies from disorders caused by exogenous factors such as tobacco and autoimmune inflammation to idiopathic or inherited genetic aberrations. In this review, these potentially malignant disorders (PMDs) are described regarding clinical presentation and histopathological architecture. Special attention is paid to the underlying etiologies of PMDs and the potential pathways leading to cancer. The clinical perspective focuses on the importance of accurate and timely diagnosis.