[The use of intralaboratory and external quality control of immunohistochemical studies to improve the detection of estrogen and progesterone receptors].

Immunohistochemical study of breast cancer has been practiced for several decades; however, the standardization of this process has not yet been achieved, despite substantial advances in methodology. The paper presents practical guidelines and standards for testing breast carcinomas, which can be used as day-to-day control of the work of an immunohistochemistry laboratory. It considers the concept of external quality control in the immunohistochemical detection of estrogen (ER) and progesterone (PR) receptors, as well as the problems of harmonization in the immunohistochemical analysis of breast carcinomas, by using the nuclear biomarkers, such as ER and PR, as an example. The agreed standard-based external control in determining the optimal result may yield reproducible data for use in clinical practice.