Estrogen and Progesterone Receptor (ER and PgR) status have been frequent determinants of medical decisions. The original ER and PgR assessment utilized radioligand binding (biochemical) methods, but current methods include biochemical, standard immunohistochemistry, high technology methods (image, flow, and laser scanning cytometry), and molecular biology. The proliferation of types of assessment on a wide numerical range of cells [10(or fewer)-100 (molecular assay), several hundred (standard immunohistochemistry, image cytometry), thousands (flow and laser scanning cytometry), or millions (biochemistry)] has exacerbated a long standing problem of quality control and inter-laboratory comparability, as well as that of defining a clinically meaningful cut-point for receptor positivity. We have advocated statistical standardization of receptor data with the use of standardized log units (SLU) to improve inter-laboratory comparability for a seamless management of patient data from multiple laboratories. We have also advocated the determination of clinical cut-points with multivariate investigations of the effects of the receptor on prognosis, which consider the effects of other significant factors (i.e. tumour size, nodal status, and where available, other tumour markers). Our results for ER and PgR demonstrate a continued multivariate prognostic importance for receptors after 5 or more years of follow-up and after the effects of adjuvant systemic therapy are considered. Reporting of results in SLU will facilitate the translation of newer techniques to clinical practice in the traditional domain of invasive breast cancer, as well as the treatment of breast DCIS.