[Quantitative determination with image analysis of immunohistochemically identified steroid hormone receptors in...

Oestrogen receptors were demonstrated immunohistochemically in 120 breast cancer cases; in 90 cases, progesterone receptors were additionally assessed. Immunohistochemical staining was evaluated by the so-called "immuno-reactive score" and quantified densitometrically by a method of computer-assisted image analysis. The measuring method allowed an objective evaluation of the portion of receptor-positive cells, the mean optical density and the distribution pattern of receptor concentrations within receptor-positive nuclei. Image analysis was compared with the semiquantitative evaluation by IRS. In 29 out of 58 weakly stained sections, which were scored as receptor-negative, receptor-positive cells could be demonstrated by image analysis because of the definition of an objective cut-off level for specific staining. Furthermore, three different patterns of distribution of receptor concentration could be distinguished: Type 0: receptor-negative carcinomas Type 1: homogeneous receptor expression within receptor-positive cells Type 2: heterogeneous receptor expression with high receptor concentrations in single cells. Type 2 patterns were almost exclusively found in postmenopausal patients, a dependence of expression pattern from grading was not demonstrated. These distribution patterns were found in the same manner in the expression analysis of progesterone receptor. With immunohistochemical staining only 45% of ER-negative carcinomas expressed PR, but 74% of ER-positive carcinomas. When ER was expressed heterogeneously (Type 2) PR was expressed in the same way in 62% of the cases. Beneath the exact determination of the portion of receptor-positive cells the analysis of the pattern of distribution is only possible by image analysis.(ABSTRACT TRUNCATED AT 250 WORDS)