Assessment of Immunohistochemical Expression of Lipid Peroxidation Marker 4-hydroxynonenal in Oral Lichen Planus – A Retrospective Study

Introduction: Oral lichen planus (OLP) is a relatively common chronic inflammatory condition of unknown origin and is classified among oral potentially malignant disorders (OPMDs). Emerging evidence suggests that oxidative stress (OS) and compromised antioxidant defense may play a role in its pathogenesis. OPMDs represent morphologically altered tissues with a risk of progression to oral cancer. Therefore, identifying high-risk lesions with a greater likelihood of malignant transformation is crucial. This study aimed to evaluate and compare OS levels by assessing the immunohistochemical (IHC) expression of 4-hydroxynonenal (4-HNE), a marker of lipid peroxidation (LPO), in OLP tissues versus normal oral mucosa. Materials and Methods: The study included 30 formalin-fixed, paraffin-embedded tissue samples from histopathologically confirmed cases of OLP and 10 normal oral mucosa samples serving as the control group. All tissue sections were subjected to immunohistochemical staining using the 4-HNE antibody and examined under a light microscope. Statistical analysis was performed using Fisher’s exact test. Results: A significantly elevated cytoplasmic expression of 4-HNE protein was observed in the epithelial cells of lichen planus (LP) tissues compared to normal oral mucosa ( P < 0.001). Approximately 90% of the normal tissue samples showed no detectable 4-HNE immunoreactivity. Conclusion: These oxidative modifications suggest underlying pathophysiological changes primarily localized to the basal cell layer and the epithelial–connective tissue interface in LP tissues. Further research is needed to explore the role of OS across different clinical and histopathological variants of LP, to enhance early prediction of malignant transformation.