The Impact of Nucleolar Organizer Regions for the Lymph Node Spread and Prognosis of Invasive Ductal Mammary Carcinoma

In primary tumours of 40 patients with invasive ductal carcinomas the significance of nucleolar organizer regions (NORs) for metastatic spread to the axillary lymph nodes and for the prognosis was assessed. Silver-stained tissue sections were investigated by means of semiautomated image analysis. The nucleolar organizer regions of 100 tumour cell nuclei per specimen were measured. The number as well as the area of the NORs were evaluated together with morphometrical and DNA features, histopathological and clinical data. By means of multivariate discriminant analysis, significant differences between tumours of 20 node-negative and 20 node-positive patients could be found. The mean number of NORs was significantly higher in patients with lymph node metastases (p = 0.0059), whereas the mean area was significantly lower in node-positive patients. By using the NOR number as the only parameter both groups were classified with an overall efficiency of 95%. There was also a significant difference between long-term and short-term survivors by considering the mean number of NORs, but the Auer-type, the 2 cDl value, and the DNA-grade of malignancy were of better predictive value. Within the group of node-negative patients the NOR number was most suitable for distinguishing between good and poor prognosis, whereas within the group of node-positive patients once more the DNA parameters played the most decisive role for predicting prognosis. With regard to the small number of patients the results have to be considered as preliminary. Further investigations in a more extensive population are necessary.