[Proposal for a semiqualitative evaluation method for AgNORs (rap score)].

Nucleolar Organiser Regions (NORs) can be stained in paraffin embedded specimens by a simple silver technique: the black dots formed, called AgNORs, have usually been counted only by eye with "careful focusing", a time-consuming and subjective method. Therefore we propose a new semiquantitative approach based on three patterns of AgNORs configuration of increasing malignancy as previously described by Crocker et al: 1) AgNORs fully aggregated to form a solitary argyrophil structure (pattern RESTING: -R-); 2) AgNORs lying within nucleolus and nucleoplasm (Pattern ACTIVATED: -A-); 3) Numerous small AgNORs distributed through the nucleoplasm, without nucleolar structures (Pattern PROLIFERATING: -P-). We assigned a numerical value to each pattern: R = 1; A = 2; P = 3. These values are multiplied by the relative rate in 100 cells. Eventually we obtain a score (range 100-300): this method shows significant correlation (r = 0.8363: regression equation) compared to the usual count obtained "by eye", tested on a sample of 150 breast cancer. Further studies are under way to validate this method which may represent a cheap and useful tool in AgNORs evaluation.