Evaluation of argyrophilic nucleolar organizer regions in tongue squamous cell carcinomas

Using a silver staining technique, argyrophilic nucleolar organizer regions (AgNORs) were studied on the biopsy specimens taken from 67 tongue squamous cell carcinomas (SCCs), and the relations of the results of AgNORs to the clinicopathological findings, to the labelling indices of proliferating cell nuclear antigen (PCNA LI), and to the outcomes of the disease were investigated. The mean numbers of AgNORs per cell were 1.67 +/- 0.19 (n = 27) in the control squamous epithelia and 3.58 +/- 1.15 (n = 67) in the tongue SCCs, respectively, and a significant difference was found between the two groups (P < 0.0001). Concerning the clinicopathological findings, the mean numbers of AgNORs in the progressive cases (T3, T4), in the factor N-positive groups (N1, N2), and in the advanced stages (stages III, IV) were statistically higher than those in T1, T2, N0, and earlier stage (stages I, II) tumours, respectively. Similarly, a higher value of the AgNOR count was present in the histological grade III or diffuse invasive tumour. There was also a directly significant correlation between the AgNOR counts and the labelling indices of PCNA (r = 0.53, P < 0.0001). Concerning the outcome of the disease, the mean numbers of AgNORs were higher in the group with local recurrence or with lymph-node metastasis. A lower rate of 5 years' survival was found in the high value group (63.5%) of AgNORs compared with that of the low value group (86.0%), with a significant difference between the two groups (P < 0.05). The results suggest that AgNORs may reflect the degree of malignancy and cellular proliferation in tongue SCCs.