Background: Oral lichen planus (OLP) is categorized as premalignant lesion although its malignant potentialis a matter of controversy. The objective of this study was to investigate Ki67 expression in OLP, oral epithelialdysplasia and oral squamous cell carcinoma (OSCC). Materials and
Methods: Expression of Ki67 was evaluatedthrough immunohistochemistry (IHC) in groups of A (17 cases of epithelial hyperplasia), B (16 cases of OLP), C1(10 cases of mild epithelial dysplasia), C2 (10 cases of severe epithelial dysplasia), D1 (10 cases of well-differentiatedOSCC), and D2 (10 cases of poorly-differentiated OSCC).
Results: There was a significant difference in Ki67expression based on quantitative analysis among the six studied groups as well as group B compared bilaterallywith groups C2, D1 and D2 (p< 0.0001). However, there was no significant difference between groups B and C1or between groups D1 and D2 (p> 0.05).
Conclusions: Based on the results of the present study it may not bepossible to definitely consider malignant transformation potential for OLP. However, expression of Ki67 wassignificantly higher in OLP than that of epithelial hyperplasia with no significant difference from that of mildepithelial dysplasia. This should be considered by clinicians to carefully and regularly follow up OLP lesions todetect potential subtle changes at an early stage.