INTERPRETATION OF STEROID-RECEPTORS IN BREAST-CANCER - A CASE WITH DISCORDANT ESTROGEN-RECEPTOR RESULTS USING ER1D5 AND H222 ANTIBODIES

We report a case of an invasive duct breast cancer, grade 1 by Bloom a nd Richardson criteria, and metastatic to axillary nodes and perinodal soft tissue. Immunostaining for estrogen receptor (ER) with ER1D5 res ulted in intense positive tumor cell staining with both frozen and par affin sections. Matching studies using a different anti-estrogen recep tor reagent (H222), uniformly produced negative results in 3 different assay systems (EIA-ER, ER-ICA, ER-PAR). This case reveals a discrepan cy between reactivity of ER1D5 and H222 that may indicate the presence of outlaw ER variants. It also illustrates the interpretation problem s that can arise with new antibodies that have not been fully validate d, particularly if the results are used in therapeutic decision making .