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.

Improved method for assay of estradiol and progesterone receptors with special reference to breast cancer

Isoelectric focusing of estradiol receptor (ER) and multiple point dextran-coated charcoal (DCC) technique for progesterone receptor (PgR) were adapted for assay of both receptors in the same cytosol sample. Technical improvements and increased recovery of receptors were achieved. 1.0 fmol/ml cytosol of ER may be detected; sensitivity of PgR was 5-10 fmol/ml cytosol. Quantitation of ER was made in 414 (95%) out of 434 consecutive breast cancers. Inclusion of isoelectric focusing records showing only qualitative indication for presence of ER resulted in 98% ER containing tumours, supporting the aspect that strictly ER negative tumours are a rarity. Implications for therapy in disseminated disease are discussed.

Correlation between estradiol-17 beta and progesterone cytosol receptor concentration, histologic differentiation and 3H-thymidine incorporation in endometrial carcinoma

Women treated with estrogen exhibit a higher risk of developing endometrial cancer. steroid hormones exert their effects on target tissue through specific cytosol receptor protein. Knowledge of this steroid receptor concentration in endometrial carcinoma might facilitate the treatment of recurrences. We have compared the concentrations of endometrial estrogen and progesterone cytosol receptors with the histologic grade of endometrial carcinoma as well as the rate of 3H-thymidine incorporation. We found a significant difference in receptor concentration between well-moderately differentiated tumours and poorly differentiated ones. No correlation was found between 3H-thymidine incorporation rate and differentiation. A positive correlation between thymidine incorporation rate and progesterone receptor concentration was noticed. The concentration of receptors varies within a wide range of each group of differentiation; thus 23% and 4% of the poorly differentiated tumours had higher concentration of estradiol and progesterone receptors respectively than the median values for well differentiated tumours.