IMMUNOCYTOCHEMICAL ANALYSIS OF HORMONE RECEPTORS WITH MALIGNANT-CELLSSEPARATED FROM HUMAN MAMMARY-TUMORS

The authors compared radioligand assays with immunocytochemistry assay s to establish the hormone receptor status of malignant mammary tumors . This study differed from previous work in that immunochemistry assay s were used with tumor cell effluents rather than with intact histolog ic sections. The results showed a 90% qualitative agreement between im munocytochemistry assays and radioligand assays in identifying estroge n receptor (ER)- or progesterone receptor (PgR)-positive and ER- or Pg R-negative malignant tumors. However, only 31% of the cells from recep tor-positive patients expressed ER, and only 24% of the cells containe d PgR. The data showed a 73% agreement between immunocytochemistry and radioligand assays for ER when cases were categorized as strongly pos itive (> 100 fmol/mg and > 10% stained cells), intermediately positive (3-100 fmol/mg and .1% to 10% stained cells), or negative in both ass ays. Progesterone receptor values for the three categories showed an a greement between assays of 82%. These observations suggest that immuno cytochemical analysis of isolated populations of tumor cells may be a useful means of complimenting radioligand assays in selecting patients for antihormone therapy.