Estimation of argyrophilic nucleolar organizer regions in different grades of oral submucous fibrosis

CONTEXT: Assessment of potential for malignant transformation of oral submucous fibrosis (OSF) through clinical or light microscopic examination of hematoxylin and eosin stained tissue sections is not totally satisfactory. The search is for such a tissue marker that will differentiate those cases of OSF, which carry a higher risk for malignant transformation. During the past few years, numerous workers have validated the usefulness of enumerating argyrophilic nucleolar organizer regions (AgNORs) in predicting the malignant potential of lesions. The present study was carried out to validate the diagnostic potential of this marker. OBJECTIVES OF THE STUDY: Quantitative and qualitative assessment of AgNORs in different grades of OSF and to compare the count of AgNORs in different grades of OSF and normal mucosa. MATERIALS AND METHODS: AgNORs were investigated in tissue specimens from 90 patients diagnosed with different histopathological grades of OSF. AgNORs were identified in tissue specimens stained with silver nitrate, using light microscope. AgNORs were counted as small, large and total count to analyze them both quantitatively and qualitatively. STATISTICAL ANALYSIS USED: Results were subjected to statistical analysis for obtaining significance value (P value) by unpaired Student's t-test. RESULTS: The mean total count of AgNORs was 2.464 ± 0.101, 4.358 ± 0.108, 3.704 ± 0.106 and 3.279 ± 0.161 in normal mucosa, Grades I, II and III of OSF, respectively. A qualitative difference was observed in the presentation of AgNORs in different grades of OSF. Mean value of small nucleolar organizer regions (NORs) decreased while the mean of large NORs increased as the grade of OSF increased. CONCLUSIONS: The study findings suggest that AgNORs are increased in OSF and they can serve as a reliable tool adjunct to histopathological diagnosis. Their ease of demonstration and high specificity to cellular proliferation make them the best available histopathological marker in the arsenal of an oral pathologist.