REVERSE TRANSCRIPTION-POLYMERASE CHAIN-REACTION (RT-PCR) ASSAYS OF ESTROGEN AND PROGESTERONE RECEPTORS IN BREAST-CANCER

The biochemical assay for estrogen (ER) and progesterone receptors (PR ) as a routine procedure in the clinical evaluation of human breast ca ncer is well established. Since there are various and complex phenotyp ic alterations in breast cancer, there is a need for a multiparametric assessment of the biological profile of breast tumours. However, mult iparametric analysis requires a large amount of tissue and various met hods of quantitative analysis involving expensive reagents. Thus, an e valuation of the di agnostic and prognostic applications of the measur ement of mRNA expression by reverse transcription polymerase chain rea ction (RT-PCR) has been initiated. A series of 105 surgical samples of breast cancer was assayed for ER and PR expression in parallel by sem i-quantitative RT-PCR and standardized enzymoimmunoassays (EIA). 79 (7 5%) tumour samples were positive for ER expression by EIA, and 86 (82% ) by RT-PCR. This shows a good concordance of the two methods (90%). I n the case of PR expression 65 (62%) tumour samples were positive by E IA and only 53 (51%) samples by RT-PCR. In conclusion ER-RT-PCR appear s to provide information concerning ER expression similar to ER-EIA, a nd may be an alternative to this assay. The information derived by PR- RT-PCR appears somewhat different from PR-EIA. We are currently evalua ting the biological and clinical significance of this discrepancy.