ESTROGEN AND PROGESTERONE-RECEPTOR MESSENGER-RNA LEVELS IN PRIMARY BREAST-CANCER - ASSOCIATION WITH PATIENT SURVIVAL AND OTHER CLINICAL ANDTUMOR FEATURES

The relative expression of estrogen receptor (ER) and progesterone rec eptor (PR) mRNA transcripts was measured in 71 primary breast-cancer b iopsies. ER and PR binding activity were estimated in parallel by the dextran-coated-charcoal method. There was a close correlation between the amount of ER mRNA and estradiol binding activity. Tumors from post -menopausal patients contained higher levels of ER mRNA than those fro m pre-menopausal patients. Northern-blot analysis indicated the presen ce of a major band of 6.3 kb in all ER mRNA-positive tumors. Some tumo rs showed, in addition, 3.7- and 2.4-kb transcripts. PR binding activi ty and overall PR mRNA levels correlated moderately. PR mRNA and ER mR NA were associated. Four PR mRNA species with estimated sizes of 11.4, 4.5, 3.7 and 2.5 kb were detected in 14% of the PR mRNA-positive tumo rs. The 3.7-kb transcript was detected to varying degrees in all PR mR NA-positive biopsies, accompanied in some tumors by the 2.5-kb species . ER and PR mRNA levels greater than or equal to 50 pg/5 mu g total RN A correlated with prolonged survival of the patients. In addition, hig h ER mRNA levels were associated with absence of necrosis and vascular invasion together with absence or minimal level of tumor lymphocytic infiltration, but not with age, clinical stage, tumor size or overexpr ession of c-myc or c-erbB-2 mRNA. PR mRNA was not statistically associ ated with any of the above clinicopathological features. A bivariate a nalysis showed that both ER and PR mRNA levels were able to predict ov erall survival independently of the lymph-node status.