Nucleolar Organizer Regions - A Tissue Marker in Oral Submucous Fibrosis
Anita Balan1, R Rajendran2 1 Oral Medicine and Radiology, Dental College, Trivandrum, India 2 Department of Oral Pathology and Microbiology Dental College, Thiruvananthapuram, Kerala, India
Source of Support: None, Conflict of Interest: None
Background: Oral Submucous Fibrosis (OSF) is a chronic insidious condition with a high risk for cancer development. Assessment of malignant potential of OSF through clinical or light microscopic tissue sections is not totally satisfactory. A tissue marker that will be useful in prognostication can benefit in its clinical management.
Method: Nucleolar organizer regions (NORs) are loops of ribosomal DNA found in the nucleolus that can transcribe for ribosomal RNA. The nonhistone nucleoproteins associated with NORs can be identified by silver staining (AgNORs). AgNOR staining of formalin fixed paraffin embedded biopsy specimens from 28 OSF patients and 10 normal persons was done. The relationship of mean AgNOR count to both the clinical stage and histological grades of disease was studied.
Results: There was significant progressive increase in pooled mean AgNOR counts with increasing grades of OSF. Mean AgNOR counts of OSF with coexisting carcinoma was significantly higher. When clinical staging was considered a wider range of mean AgNOR counts was seen.
Conclusion: AgNOR counts can be used as a simple and reproducible biological marker of impending malignancy. This could be treated as a advantage over conventional histopathology and / or clinical staging of the disease.