Immunocytochemical analysis of hormone receptors with malignant cells separated from human mammary tumors.

ABSTRACT

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