Background and aims. Several diagnostic methods are being employed to detect benign and malignant lesions, one of
which is silver nitrate staining for organizer regions. The number of nucleolar organizing regions (NORs) can be used to
show the degree of cell activity or metabolism in pathologic lesions. This study was designed to evaluate NORs as determinants
of precancerous and squamous cell carcinoma.
Materials and methods. A silver colloid technique was applied on paraffin sections of 40 cases of oral squamous cell
carcinoma and 25 cases of precancerous lesions; 15 specimens of normal epithelium were selected for the control group.
After staining with silver nitrate, argyrophilic nucleolar organizer regions (AgNORs) were counted in 100 epithelial cells in
three groups with the use of an oil immersion and ×1000 objective lens. One-way ANOVA and a post hoc Tukey test were
used for statistical analysis.
Results. The mean numbers and standard deviations of AgNORs were 1.58 ± 0.76 in normal epithelium, 2.1 ± 1.05 in precancerous
lesions and 2.43 ±1.33 in squamous cell carcinoma (SCC). There were statistically significant differences in AgNORs
numbers between the groups (P<0.001) and significant differences in precancerous lesions between dysplastic and
non-dysplastic epithelia (P<0.001). The mean AgNORs count per nucleus increased from healthy epithelium to precancerous
lesion to SCC.
Conclusion. This study suggests that the silver staining technique for the detection of NORs (AgNOR) can be used to
distinguish precancerous lesions and benign and malignant lesions
