Hormone receptor assays and their value in breast cancer therapy

Quantitation of progesterone receptor mRNA in breast carcinoma by branched DNA assay

Expression of progesterone receptor (PR) mRNA is indicative of a normal gene regulation mechanism mediated by functional estrogen receptor (ER). A simple assay which can reliably detect and quantitate PR mRNA levels in a small amount of tissue will be of value for studying functional status of ER. We have developed a quantitative nucleic acid hybridization assay for PR mRNA in breast carcinoma. The assay, which is based on the branched DNA (bDNA) technology, is simple, highly specific, and reproducible, requires 20 mg of tissue, and correlates reasonably well (r = 0.86) with an established methodology. The assay has a dynamic range of 3 x 10(3)-6 x 10(7) copies of PR mRNA per well. PR message as high as 3.9 x 10(5) copies per well could be detected in normal breast tissues. Thus a sensitivity of 3 x 10(3) PR copies per well was sufficient for testing clinical samples. In the present studies, accurate measurement of tissue weight enabled direct reporting of the PR mRNA values as the end point results. The bDNA assay provides a useful tool for the detection and quantitation of PR mRNA in research and routine clinical laboratories.

Quantitation of estrogen receptor mRNA in breast carcinoma by branched DNA assay

A quantitative nucleic acid hybridization assay for determination of estrogen receptor (ER) mRNA in breast carcinoma is described. The assay, which is based on the branched DNA (bDNA) technology, requires 20 mg of tissue, is simple, highly specific, and reproducible, and correlates reasonably well with an established methodology (r = 0.87). The assay has a dynamic range of 3 x 10(3)-6 x 10(7) copies of ER mRNA per well. ER message as high as 2.5 x 10(6) copies per well could be detected in normal breast tissues. Thus a sensitivity of 3 x 10(3) ER copies per well was sufficient to analyze clinical specimens. In the present studies, accurate measurement of tissue weight enabled direct reporting of the ER mRNA values as the end point results. The bDNA assay provides a useful tool for the detection and quantitation of ER mRNA in research and routine clinical laboratories.