[Nucleolar organizers in superficial bladder tumors. Prognostic analysis of 37 observations]

Nucleolar Organisers (NORs) are intranucleolar segments of DNA coding for ribosomal RNA. The agyrophilic proteins (AgNOR) associated with NORs allow them to be cytolabelled on paraffin sections. The number of NORs (NOR index) is correlated with cellular proliferation and has a diagnostic and prognostic value in neoplastic disease. The AgNOR method was analysed in a series of 37 superficial bladder tumours with different clinical courses. The NORs were counted in normal urothelium, on superficial tumours used to establish the diagnosis of the disease and on recurrent superficial tumours. The NOR index was 4.54 for normal urothelium, 5.89 for non-invasive superficial tumours, 7.33 for invasive superficial tumours, and 9.75 for invasive recurrences. These results demonstrate an increase in nucleolar argyrophilia with invasion and invasive potential of superficial bladder tumours which were initially homogeneous for stage and grade. The AfNOR method could constitute a new method of early histoprognostic evaluation for urothelial tumours.