Methods and apparatus for the quantitation of nuclear proteins

Abstract

An image analysis system is used for the quantitation of nuclear proteins in cell populations. Particularly, the hormonal receptor content of fine needle aspirates of human breast carcinomas are evaluated. Estrogen or progesterone receptors are amplified and visualized in the specimen by a staining technique of the immunoperoxidase type. Monoclonal antibodies specific against the receptor are attached to the receptor sites and are then amplified by a bridging antibody which attaches to the monoclonal antibody and a peroxidase-antiperoxidase complex. A chromagen, diaminobenzidine is combined with the complex and treated with hydrogen peroxide to react with the peroxidase forming an insoluble brown precipitate which marks the receptor sites for optical identification. The specimen is then counterstained with another chromagen, methyl green which is specific to the nucleus of each cell. Two monochromatic filterings optionally separate the areas stained by the receptor site optical enhancer and the nuclear area optical enhancer. Measurements of the optical density values of the stained receptor areas yield an intensity value directly related to the quantity of hormonal receptor in the specimen. A comparison of the nuclear area containing hormonal receptor with the total nuclear area yields a percentage value which indicates the distribution of cells throughout of the specimen which contain receptor. These two values for intensity and distribution are then combined to yield a predictive score for an assay. The measured score when compared to an empirically derived reference score is predictive of the prognosis of endocrine therapy.