Tumor proliferative fraction in infiltrating duct carcinoma.

Deregulated cell proliferation is a key factor in malignancy and therefore may be of prognostic significance. Both Proliferating Cell Nuclear Antigen (PCNA) and silver binding Argyrophilic Nucleolar Organizer Regions (AgNORs) have been established as a valuable reflection of the tissue proliferative compartment and hence could be of value in studying the biologic behavior of malignant cells. In the present study, we evaluated the proliferative activity of 120 infiltrating duct carcinomas by analysing for PCNA and AgNOR expression in relation to pathologic variables. The AgNOR scores were significantly greater in the malignant tissue than in benign lesions. Expression of PCNA was also found to be increased in malignant breast tumors, when compared to controls. A strong positive correlation between PCNA immunoreactivity and AgNORs was evident. There was also a positive correlation between histologic grading and AgNOR score in breast cancer (r = 0.92, p = 0.000). Tumor with elevated AgNOR counts were often poorly differentiated. It is therefore apparent that evaluation of AgNORs and PCNA may help in the elaboration of histopathologic grading of infiltrating duct carcinoma and may be of prognostic significance.