USE OF ANTIBODIES AGAINST ESTROGEN AND PROGESTERONE RECEPTORS TO IDENTIFY METASTATIC BREAST AND OVARIAN CARCINOMAS BY CONVENTIONAL IMMUNOHISTOCHEMICAL AND TYRAMIDE SIGNAL AMPLIFICATION METHODS

The immunohistochemical detection of estrogen receptors (ERs) and prog esterone receptors (PRs) is useful for the differentiation of cytostat ically treatable breast and ovarian carcinomas from other metastatic a denocarcinomas of unknown primary sites. We retrospectively studied me tastases of 68 breast, 24 ovarian, 15 bronchogenic, 35 gastric, 22 pan creatic, 23 colonic, 27 renal cell, and 26 primary bronchogenic carcin omas by using a panel of 3 antibodies against ERs and 4 antibodies aga inst PRs and applying both a conventional immunohistochemical detectio n method and the highly sensitive tyramide signal amplification (TSA) technique. Antibody 6F11 against ERs was slightly more sensitive than clone 1D5 with both detection methods, staining 5% more breast carcino mas and 4% more ovarian carcinomas with TSA, compared with conventiona l immunohistochemical analysis. Furthermore, clone 6F11 detected ERs i n 4 of 26 primary bronchogenic carcinomas and 1 of 35 metastases of ga stric carcinomas with conventional immunohistochemical techniques; an additional 9 primary and 6 metastatic bronchogenic carcinomas and 2 me tastatic gastric carcinomas were positive with TSA The resulting speci ficities for breast and ovarian carcinomas versus all other carcinomas were 0.97 with conventional immunohistochemical techniques and 0.85 w ith TSA. Antibody 1A6 against PRs was slightly more sensitive but leas t specific for breast and ovarian carcinomas (specificity was 0.96 wit h conventional immunohistochemical methods and 0.91 with TSA), compare d with antibody hPRa3 and a polyclonal antibody (specificity was 1.00 with both detection methods). Antibodies TE111 against ERs and 10A9 ag ainst PRs were significantly less sensitive than the other antibodies. We conclude that TSA cannot be recommended for the detection of ERs a nd PRs to differentiate breast and ovarian carcinomas from other metas tatic adenocarcinomas of unknown primary sites.