IMMUNOHISTOCHEMICAL EXPRESSION OF OCT4 IN ORAL POTENTIALLY MALIGNANT DISORDERS

Abstract

Background

Oral potentially malignant disorders (OPMDs), including oral leukoplakia (OL) and oral submucous fibrosis (OSMF), are recognized precursor lesions of oral squamous cell carcinoma (OSCC) with varying risks of malignant transformation. Conventional histopathological grading remains the gold standard for assessing malignant potential; however, its predictive value is limited by interobserver variability. Cancer stem cell (CSC) markers have emerged as promising molecular biomarkers for identifying high-risk lesions. Octamer-binding transcription factor 4 (OCT4), a key regulator of stem cell pluripotency and self-renewal, has been implicated in tumor initiation, progression, and resistance to therapy. This study evaluated the immunohistochemical expression of OCT4 in OPMDs and investigated its association with histopathological severity.

Materials and Methods

A retrospective immunohistochemical study was conducted on 40 formalin-fixed, paraffin-embedded tissue specimens comprising 10 cases of normal oral mucosa (NOM) and 30 cases of OPMDs, including oral leukoplakia with mild (n = 9), moderate (n = 4), and severe epithelial dysplasia (n = 4), and oral submucous fibrosis Grade I (n = 3), Grade II (n = 10), and Grade III (n = 11). Immunohistochemical staining was performed using monoclonal anti-OCT4 antibody. The percentage of OCT4-positive cells was evaluated by semi-quantitative analysis, and staining intensity was graded according to the proportion of positively stained cells. Statistical analysis was performed to determine the association between OCT4 expression and histopathological grade.

Results

OCT4 expression showed a progressive increase with increasing severity of oral epithelial dysplasia. The mean OCT4 expression was 1.70 ± 1.25% in normal oral mucosa, 1.78 ± 2.77% in mild dysplasia, 15.50 ± 0.58% in moderate dysplasia, and 37.25 ± 9.50% in severe dysplasia. Within the OSMF group, OCT4 expression was 1.33% in Grade I, 0.00% in Grade II, and increased to 4.50% in Grade III lesions. Overall, 70% of OPMD cases demonstrated negative staining (0–5% positive cells), whereas 30% exhibited varying degrees of positive immunoreactivity. Higher OCT4 expression was associated with increasing dysplastic severity, indicating enhanced cancer stem cell activity during early oral carcinogenesis.

Conclusion

The present study demonstrates that OCT4 expression increases progressively with the severity of oral epithelial dysplasia, suggesting its involvement in the early stages of oral carcinogenesis.