Immunohistochemical Expression of Nuclear Factor – Kappa B in Oral Squamous Cell Carcinoma, Oral Submucous Fibrosis and Normal Mucosa

INTRODUCTION: Oral submucous fibrosis (OSF) is a chronic progressive, scarring, high risk precancerous condition of the oral mucosa seen primarily on the Indian sub continent and in South east Asia1. The disease was first reported in 1952 by Schwartz and in 1953, Joshi redesignated the condition as Oral Submucous Fibrosis, implying predominantly its histological nature. The condition is characterized by mucosal rigidity of varying intensity due to fibroelastic changes in juxta epithelial layer, reduction in vasculature and epithelial atrophy resulting in a progressive inability to open the mouth. AIMS AND OBJECTIVES: 1. To evaluate the expression of NF - κB in formalin fixed paraffin embedded tissues of oral squamous cell carcinoma by immunohistochemistry. 2. To evaluate the expression of NF- κB in formalin fixed paraffin embedded tissue of OSF by immunohistochemistry. 3. To evaluate the expression of NF- κB in formalin fixed paraffin embedded tissue of normal buccal mucosa by immunohistochemistry. 4. To compare the expression of NF- κB in oral squamous cell carcinoma, oral submucous fibrosis and normal buccal mucosa. MATERIAL AND METHODS: Study setting: The study was conducted in Department of Oral and Maxillofacial Pathology, Ragas Dental College and Hospital, Chennai, using paraffin embedded tissues. A cross-sectional study was done to evaluate the expression of NF-κB in oral squamous cell carcinoma, oral submucous fibrosis and normal buccal mucosa using immunohistochemistry in formalin fixed, paraffin embedded tissue specimens. Study sample size: The study material comprised of 40 formalin-fixed, paraffin embedded tissue specimens (archival blocks). 1. 20 histopathologically confirmed oral submucous fibrosis tissue specimens. 2. 10 histopathologically confirmed oral squamous cell carcinoma tissue specimens. 3. 10 normal buccal mucosa tissues specimens. Study subject: The study comprised of 3 groups: Group I – (CASES) : 10 patients of oral squamous cell carcinoma, diagnosed clinically and confirmed histopathologically, were selected. Inclusion Criteria: Clinical: • A non-healing ulcerated lesion with indurated base or exophytic, fungating or papillary growth was considered as OSCC. Histopathological: • Characterized by invasive islands and cords of malignant squamous epithelial cells in the connective tissue. Group II- (CASES) : 20 patients of OSF, diagnosed clinically and confirmed histopathologically, were selected. Inclusion Criteria: Clinical: 1. Habit of chewing areca nut in some form. 2. The presence of fibrous bands in the labial and/ or buccal mucosa. 3. Loss of elasticity of the buccal/ labial mucosa. 4. Restriction of mouth opening. Histopathological: 1. Juxtaepithelial hyalinization. 2. Submucosal dense and vascular collagenous connective tissue. 3. Epithelial atrophy. 4. Variable number of chronic inflammatory cells. Group III- (CONTROLS) : 10 patients who had clinically normal buccal mucosa, reporting to the outpatient department of oral and maxillofacial surgery for removal of impacted third molar constituted the control group. Inclusion Criteria 1. They had no habit of smoking, alcohol consumption or chewing areca nut. 2. They were apparently healthy with no systemic disorders. 3. They were not on any medications for systemic diseases like hypertension, diabetes. Methodology 1. A detailed case history including age, sex, and occupation, past medical & dental history, history of habits, drugs and trauma were recorded. 2. General examination and intra oral examination was done. 3. Biopsy was done in both cases and controls. 4. The tissue taken was immediately transferred to 10 % buffered formalin. 5. After adequate fixation, tissues were embedded in paraffin. 6. From the paraffin embedded blocks 4 micron thick, sections were cut and used for routine hematoxylin and eosin (H & E) staining and immunohistochemical (IHC) staining. 7. This project was approved by Institutional Review Board (IRB) of Ragas Dental College and Hospital, Chennai and patient consent was taken. SUMMARY: 1. A total of 40 patients were included in the study, comprising of 10 cases of OSCC (group I), 20 cases of OSF (group II) and 10 patients with normal oral mucosa (group III). 2. In OSCC, there was 100% positivity of NF – κB staining; with 70% of cytoplasmic expression and 30% of nuclear expression. Moderate to intense cytoplasmic expression was seen in suprabasal layer. 3. In OSF; there was 85% positivity of NF – κB expression; with 55% of cytoplasmic expression and 30% of nuclear staining. 4. Comparison of intensity of staining between the basal and suprabasal layer within the epithelium in OSF was statistically significant. 5. In normal mucosa, there was 60% of positivity of NF – κB expression within 50% of cytoplasmic expression and 10% of nuclear expression. Comparison of intensity of staining between basal and suprabasal layer within epithelium of normal mucosa was statistically significant 6. There was no statistically significant difference in the epithelial staining intensity between OSF & OSCC, OSF and normal, and also between OSCC and normal. 7. Nuclear expression of NF – κB when compared between the groups was not statistically significant. CONCLUSION: In conclusion our result showed that there is increased expression of NF – κB in OSCC and OSF when compared to normal. Although staining intensity and mean labeling index did not show any significant difference between OSCC and OSF, further studies on a larger sample will help in ascertaining the significance of NF – κB expression in OSF samples