IMMUNOHISTOCHEMICAL DETERMINATION OF NUCLEAR ANTIGENS BY COLOR IMAGE-ANALYSIS - APPLICATION FOR LABELING INDEX, ESTROGEN AND PROGESTERONE-RECEPTOR STATUS IN BREAST-CANCER

The immunohistochemical evaluation of 5-bromo-2'-deoxyuridine (BrdU) l abelling index, estrogen (ER) and progesterone receptor (PR) status wa s carried out on the automated computer-assisted image analysis statio n BIOCOM 500. Special software has been developed to measure nuclear a ntigens using the immunoperoxidase method with the Harris hematoxylin counterstain. The analysis was based on the different light adsorption spectra of the chromogen diaminobenzidine and Harris's hematoxylin co loration when exposed to light of differing wavelengths, The results o btained by image analysis were compared to previously validated method s. The thymidine labelling index performed by manual procedures and Br dU incorporation performed by image analysis were comparable (linear c orrelation coefficient r = 0.76, P < 0,001). Comparison of image analy sis and dextran coated charcoal assay for ER and PR content revealed e xcellent sensitivities and specificities (linear correlation coefficie nt r = 0.87, P < 0.001,for ER and r = 0.93, P < 0.001 for PR). These d ata suggest that automated image analysis offers a reliable and reprod ucible procedure for measuring nuclear antigens.