Assessment of immunohistochemical expression of oxidative stress marker 8-OHdG in oral lichen planus

Abstract

Oral lichen planus (OLP) is a chronic inflammatory condition that has been clinically linked with the risk of developing oral cancer. The present study aimed to determine the oxidative stress in oral lichen planus (OLP) by assessing the immunohistochemical (IHC) expression of 8-hydroxydeoxyguanosine (8-OHdG) in OLP tissue samples and comparing it with that of normal oral mucosa. The study group consisted of 30 formalin-fixed, paraffin-embedded (FFPE) tissue blocks from oral lichen planus (OLP) cases, while 10 normal oral mucosa samples served as the control group. Tissue sections of 5-micron thickness were prepared and immunostained with the 8-hydroxydeoxyguanosine (8-OHdG) antibody. The stained slides were examined under a light microscope, and statistical analysis was conducted using Fisher's exact test. A significant increase in oxidative DNA damage marker 8-OHdG expression (p < 0.05) was observed within the basal and suprabasal epithelial layers of lichen planus tissue samples. In contrast, no immunoreactivity was detected in the normal oral mucosa. Excessive production of reactive oxygen species (ROS) during chronic inflammation is believed to play a crucial role in inducing DNA damage. The mutagenic marker 8-hydroxydeoxyguanosine (8-OHdG) in oral lichen planus tissue highlights its potential as a biomarker for assessing the risk of inflammation-driven carcinogenesis. Further research, incorporating various oxidative stress markers and clinicopathological correlations, is essential to enhance early prediction of malignant transformation in oral lichen planus.

Keywords: 8-OHdG; Oral lichen planus; immunohistochemistry; oxidative DNA damage; oxidative stress.