Nucleolar organizer regions and Ki-67 immunostaining in ductal breast cancer: a comparative study.

53 cases of invasive ductal (NOS) carcinomas of the breast were studied by means of an immunostaining method with Ki-67 monoclonal antibody and an argyrophilic method for the demonstration of Nucleolar Organizer Regions (AgNORs). The percentage of cancer cells with nuclear Ki-67 immunoreactivity and the mean number of NORs for each tumour were statistically related. The data obtained showed a good correlation between Ki-67 index and NOR score (rS = 0.47 - P less than 0.001). The authors suggest that the AgNOR method--which is applicable to routinely processed material--might effectively substitute Ki-67 immunostaining as a marker of cell proliferation in ductal breast cancer.