A comparison of two steroid receptor assays in breast cancer: dextran coated charcoal and isoelectric focusing.

The multiple point dextran coated charcoal technique with Scatchard analysis (DCC) and isoelectric focusing on polyacrylamide gels (IF) were compared with regard to steroid receptor recovery, amount of tissue necessary, and expenses of assay. Quantitative correlations showed that when using DCC as compared to IF, estradiol receptor (ER) recovery increased two and progesterone receptor (PgR) recovery increased four times. In spite of lower recovery, IF may be a good alternative to DCC for routine ER assay since a small amount of tissue is required and the IF assay is easy to evaluate. The two assays were approximately equal in expense.