Detection of the oestrogen receptor (ER): immunohistochemical versus cytosol measurements

Oestrogen receptor (ER) content gives a direct indication of the chances th at a breast cancer patient will show a sustained response to endocrine ther apy. Thus, an ER value should be recorded for every breast cancer patient. ER was traditionally measured by a ligand binding assay (LBA). LBA is not s uitable for all routine hospitals in which breast cancer is treated. More a ppropriate is immunohistochemistry (IHC). This paper identifies advantages and disadvantages of both assays, suggests that both methods predict equall y response to endocrine therapies and describes a simple, semi-quantitative IHC for which external quality assurance works successfully. (C) 2000 Else vier Science Ltd. All rights reserved.