Development of two ELISA for estrogen and progesterone receptor with sufficient sensitivity for fine needle aspirate and core biopsy

The quantitative determination of estrogen and progesterone receptors (PR a nd ER) in breast tumor cytosol has been routinely performed in clinical lab oratories to aid in the selection between hormonal and chemotherapy and als o to predict prognosis. However, the small amount of tissue available from the increasingly popular fine-needle aspiration and core biopsies from brea st cancer patients requires more sensitive immunoassays for receptor quanti fication. We have developed two sensitive immuno-assays for ER and PR on mi croplate with the use of recently available anti-ER and anti-PR antibodies of higher affinity and a powerful signal magnification agent, namely Amdex. The calibrator was a pooled breast tumor cytosol used as calibrator and ca librated against Abbott kits. The protein concentration of the cytosol and the upper normal cutoffs for our assays were reduced to approximately 0.2 m g/mL and 3 fmol/0.2 mg/ mL, respectively. Both assays have sensitivities cl ose to 1 fmol/mL, which are sufficiently sensitive for the receptor quantif ication in fine-needle aspiration biopsies and cord biopsies of breast tumo r. J. Clin. Lab. Anal. 15:138-143,2001. (C) 2001 Wiley-Liss, Inc.