Aim: Immunohistochemical evaluation of hormone receptors (ER, PR) and correlation of immunohistochemical and morpho-clinical data.
Materials and methods: The study was performed on paraffin-embedded and HE-stained tissues originating from 100 cases of invasive mammary carcinoma. Monoclonal antibodies, anti-estrogen and anti-progesterone receptors, were used for the immunohistochemical study. The detection system was EnVision HRP and the visualization system was 3,3'-diaminobenzidine tetrahydrochloride (DAB). The evaluation of the result was performed using the Allred score.
Results: The majority of the studied cases (57%) expressed both types of hormone receptors and in 32% of the cases the hormone receptors were completely absent. The rest of the cases presented a heterogeneous phenotype: 7% presented the ER-÷PR+ phenotype and 4% the ER+÷PR- phenotype. Compared with the classical phenotype (ER+÷PR-), ER+÷PR- tumors were more frequent at patients over 50-year-old. The tumors with ER+÷PR- were larger than the ER+÷PR+ and they were of the invasive ductal carcinoma type with an Allred score for ER under 6.
Conclusions: The predictive value is amplified when the ER status is correlated with the PR status because the heterogeneous phenotypes are identified, especially the ER+÷PR- phenotype, which have an aggressive behavior and the lowest response to tamoxifen therapy.