Oestrogen and progesterone receptors in screen-detected breast carcinoma: an immunohistological study using paraffin sections.

The presence of oestrogen and progesterone receptors was studied in paraffin sections of 81 screen-detected breast carcinomas using the monoclonal antibodies ER-ICA and PgR-ICA (Abbott) and the immunoperoxidase technique. The immunohistological results were compared with the results of the standard dextran-coated charcoal biochemical assay in 28 tumours which were big enough to provide tumour tissue for this assay. Sixty-three cases (78%) were oestrogen receptor positive and 62 (77%) were progesterone receptor positive. There was no statistical difference between receptor positivity in palpable or impalpable, in situ or invasive tumours. In the 28 cases where the biochemical assay was carried out, the two methods gave similar results in 23 (82%) and 21 (75%) tumours for oestrogen and progesterone receptors respectively. The majority of the remaining tumours, with one exception, were positive with immunohistology and negative with biochemistry. A good correlation was also present between the mean numerical biochemical values and the semiquantitative histological scores for both receptors. It is concluded that assessment of receptor status of small screen-detected carcinomas is feasible using routinely processed paraffin sections. There is reasonably good correlation with the results obtained by the standard dextran-coated charcoal biochemical assay, but more genuine receptor positive cases are detected by immunohistology.