Argyrophilic nucleolar organizer regions of breast tumors: Assessment of aspirated cytological materials

To investigate the correlation between argyrophilic nucleolar organizer regions (Ag-NORs)and the malignant potential of breast tumors, we analyzed Ag-NORs of cytological specimens obtained from 190 patients with various types of breast disease by preoperative aspiration biopsy. The average number of Ag-NORs per nucleus was defined as the Ag-NOR score. The Ag-NOR score was 5.7 +/- 1.7 in the group of women with breast carcinoma (n =70), 2.6= 0.4 in the group with fibroadenoma (n= 54) and 2.9= 0.6 in the group with mastopathy (n= 66). The level was significantly higher in breast carcinoma than in each benign disease(P < 0.001 in both cases). The score was 6.5 +/- 2.3 in the group with four or more metastatic lymph nodes (n = 21), 5.2+/- 1.2 in the group with one to three metastatic lymph node (n= 10) and 5.1+/- 1.1 in that with no metastatic lymph node (n = 39);the score was significantly (P < 0.05) higher in the groups with four or more metastatic lymph modes than in the other groups, respectively. Thus, a correlaton was observed between the Ag-NOR score and lymph node status. These data suggest that a higher Ag-NOR score reflects high-grade malignancy.