Histological Findings of Oral Epithelial Dysplasia and <scp>DKK3</scp> Expression That Can Predict Future Progression to Oral Squamous Cell Carcinoma

OBJECTIVES: Predicting the progression of oral epithelial dysplasia (OED) to oral squamous cell carcinoma (OSCC) is often challenging. This study aimed to clarify whether the criteria used to diagnose OED can also predict future carcinogenesis. We had previously identified Dickkopf WNT signaling pathway inhibitor 3 (DKK3) as a prognostic factor of OSCC. In this study, we evaluated the histological features and DKK3 expression in OED samples. METHODS: We included 78 cases of OED, including 26 cases that showed subsequent malignant transformation (MT+) and 52 that did not (MT-). Three oral pathologists individually evaluated the specimens with a binary rating, and a method combining majority voting with the kappa index was employed to ensure reliable interobserver agreement. DKK3 expression was analyzed using immunohistochemistry. RESULTS: The number of positive findings increased with the OED grade. Most findings were not significant for predicting future malignant transformation; however, DKK3 expression significantly predicted malignant transformation. CONCLUSIONS: Histological features could distinguish the grade of OED; however, they did not reflect its biological features. Nevertheless, DKK3 may be an efficient marker for the diagnosis of OED and a cancer prediction marker for OSCC.