Evaluation of the immunohistochemical expression of lipid peroxidation marker 4-HNE and comparison of the expression in various histopathological grades of oral squamous cell carcinoma

Abstract

Objective: This retrospective immunohistochemical study evaluated the expression of 4-hydroxy-nonenal (4-HNE), a marker of lipid peroxidation (LP), in oral squamous cell carcinoma (OSCC) and compared staining intensities across different histopathological grades.

Materials and methods: Archived formalin-fixed, paraffin-embedded (FFPE) tissue blocks from 55 primary OSCC patients were analysed. Normal oral mucosa samples (n = 10) served as controls. Immuno-histochemical staining intensity for 4-HNE was semi-quantitatively assessed. Data were analysed using SPSS version 20.0 (SPSS Inc., Chicago, IL). The Chi-square test compared 4-HNE expression between normal and OSCC tissues, while the Kruskal-Wallis H test assessed differences among OSCC grades. A p-value <0.05 was considered statistically significant.

Results: In normal tissues, 90% showed no staining, and 10% exhibited mild staining (median score = 0). OSCC samples displayed moderate staining in 34.5% and intense staining in 65.5% (median score = 3). Among histological grades, well-differentiated (WD) tumours showed 40% moderate and 60% intense staining; moderately differentiated (MD), 30% moderate and 70% intense; poorly differentiated (PD), 33.3% moderate and 66.7% intense staining. Expression of 4-HNE was significantly higher in OSCC compared to controls (p < 0.001) but did not differ significantly among OSCC grades.

Conclusion: Elevated 4-HNE levels in OSCC suggest enhanced oxidative stress (OS) and LP, supporting its potential as a biomarker in carcinogenesis.

Keywords: Immunohistochemistry; lipid peroxidation marker; oral cancer.