Standardized in situ AgNOR analysis in breast pathology: Diagnostic and cell kinetic implications

The aim of the present study was to assess the diagnostic value of the rece ntly standardized morphometric analysis of silver-stained nucleolar organiz er region-associated proteins (AgNORs) [30] in a variety of 155 routinely p rocessed benign and malignant breast lesions. 5 normal breast samples, 21 a denoses, 20 ductal hyperplasias, 10 atypical ductal hyperplasias, 20 in sit u and 43 invasive ductal carcinomas, 10 in situ and 26 invasive lobular car cinomas were investigated. A statistically highly significant difference wa s found between normal/ordinary hyperplastic and neoplastic breast lesions with all 4 consensus AgNOR parameters (mean area, mean number, CV of area, CV of number) evaluated. AgNOR quantity was significantly related to histol ogical grade of both in situ and invasive carcinomas. However, variable ove rlap was found between AgNOR values in different diagnostic groups. We conc lude that standardized AgNOR analysis is a prerequisite for objective and r eproductible AgNOR assessment in archival tissues. Despite its limited diag nostic utility for individual breast lesions, standardized AgNOR analysis b ears a significant potential for characterizing cell kinetic and metabolica l activity of breast lesions. This may give insight into the biological bac kground of breast carcinogenesis, differentiation and tumor progression and may also underlie the independent prognostic value of AgNORs in breast can cer.