AgNOR evaluation by image processing methods. Staining modifications and results in 126 invasive ductal breast...

To analyze cellular proliferating activity in breast cancer by means of a silver (Ag) method (AgNOR) that stains the nucleolar organizer regions (NORs), structures involved in protein transcription.

We analyzed 126 invasive ductal carcinomas and we described: (1) staining modifications aimed at improving the silver method, (2) AgNOR quantitative variables obtained by image processing methods, and (3) the existing relationship between these AgNOR variables and other established breast prognostic factors, such as Scarf-Bloom-Richardson (SBR) grading, tumor size, axillary status, DNA index, and estrogen and progesterone receptors.

All quantitative variables based on the AgNOR area showed statistically significant differences with reference to axillary status, tumor size and SBR grading. Cluster analysis based on these variables allowed us to detect two proliferation-level groups of breast carcinoma, one with a low and the other with a high proliferation level. Principal component analysis provided an AgNOR-independent component (first component) unrelated to other prognostic factors.

Cellular proliferation assessed by AgNOR quantification provides information that may improve prognostic prediction in breast carcinoma.