Prognostic biomarkers for malignant progression of oral epithelial dysplasia: an updated systematic review and meta-analysis

Oral epithelial dysplasia (OED) is a premalignant condition that carries an appreciable risk of malignant progression. The current grading system for severity, as defined by the World Health Organization, is a valuable clinical tool, but further work is required to improve the accuracy of predicting OED malignant progression. This systematic review aimed to assess progress in prognostic biomarker discovery in OED over the past 16 years. The primary objective was to update the latest evidence on prognostic biomarkers that may predict malignant progression of OED, with strict inclusion criteria of studies with a longitudinal design and long-term follow-up data to enhance the robustness and translational clinical potential of the findings. Of 2829 studies identified through the searching of five databases, 20 met our inclusion criteria. These studies investigated a total of 32 biomarkers, 20 of which demonstrated significant potential to predict malignant progression of OED. Meta-analysis demonstrated the significant prognostic value of four biomarkers: podoplanin, EGFR expression, p16 methylation, and DNA aneuploidy. Our review has identified 20 reported biomarkers with prognostic potential to predict malignant progression in OED, but their translation into clinical practice remains elusive. Further research is required, and this should focus on validating the promising biomarkers identified in large cohort studies, with adherence to standardised reporting guidelines.