Estrogen and progesterone receptor analyses in more than 4,000 human breast cancer samples. A study with special reference to age at diagnosis and stability of analyses. Southern Swedish Breast Cancer Study Group

Estrogen (ER) and progesterone receptors (PgR) were measured in the same laboratory in more than 4,000 breast cancer biopsy samples obtained from 15 different hospitals during ten years. ER was measured with isoelectric focusing and PgR with the dextran-coated charcoal method and Scatchard analysis. The distribution pattern for both ER and PgR was during this time period and for the different hospitals rather similar indicating a good stability of the analytical methods. ER concentration was positively correlated with patient age, with a higher percentage of positive samples and higher concentrations in patients greater than or equal to 50 years of age compared with patients less than 50 years. PgR concentration increased with age for patients under 50 years, but a considerable reduction of PgR concentration and of the proportion of positive samples was seen in patients between 50 and 59 years of age. Above this age the PgR concentration again increased with increasing age. The PgR/ER ratio and the proportion of ER- PgR+ samples were higher in patients under 50 years compared to older patients. ER and PgR values decreased during tamoxifen treatment, during pregnancy and after preoperative radiotherapy. Wet weight, DNA and protein were compared as reference parameters for the expression of ER and PgR concentrations. Strong correlations were obtained suggesting that similar information can be obtained with either of these reference parameters.

Enzyme immunoassay of progesterone receptor in cancerous and normal endometrial tissue. A comparison with dextran coated charcoal method

Enzyme immunoassay (EIA) was compared with the dextran-coated charcoal method and Scatchard analysis for the measurement of progesterone receptor (PgR) in cancerous and normal endometrial samples. A highly significant correlation was obtained between the two assays in both types of tissue (rs = 0.77 and 0.91, respectively; p less than 0.001). The measurable amount of PgR was usually higher with EIA (mean increase 90 and 100 per cent, respectively). EIA is suggested to be a suitable method for PgR measurement in endometrial tissue (normal and cancerous) and can also be used for analysis of PgR in the nuclear fraction.

Enzyme immunoassay of progesterone receptor in breast cancer biopsy samples. A comparison with the dextran coated charcoal method

Progesterone receptor was measured in 97 breast cancer biopsy samples with two methods, the multiple point dextran coated charcoal method with Scatchard analysis and enzyme immunoassay. The measurable amount of progesterone receptor was usually higher with enzyme immunoassay (mean increase 30%). When comparing the two techniques quantitatively a high correlation coefficient was obtained (rs=0.88; p less than 0.001). A concordance in terms of progesterone receptor positivity and negativity was obtained in 81 of the samples (84%) when using 10 fmol/ml as the borderline value. If instead the cut-off value used for clinical evaluations at our laboratory (30 fmol PgR/mg protein) was applied, the concordance increased to 94%. The lack of concordance in the remaining samples may be due to difficulties in the interpretation of the Scatchard plots, especially at low receptor concentration levels and to differences in specificity between the two methods in certain samples. One obvious advantage with enzyme immunoassay compared to the dextran coated charcoal method is that significantly less tissue is needed.

Estrogen receptor enzyme immunoassay in fine-needle aspirates from human breast cancer

An enzyme immunoassay was compared with a radioligand assay (isoelectric focusing) for estrogen receptor (ER) determination in 100 preoperative fine-needle aspirates from human breast cancer. A strong correlation (rs = 0.85) between the two estimates was found. However, ER estimates by enzyme immunoassay were 6 times higher than with isoelectric focusing, mainly due to an underestimation of ER content with the latter method in highly blood-contaminated or diluted samples. Enzyme immunoassay provided adequate ER measurement even at very high (50%) blood admixture. To study the reliability of ER measurement with enzyme immunoassay in fine-needle aspirates, a comparison was made with estimates in the corresponding surgical biopsies (65 cases). With DNA as reference parameter a significant correlation (rs = 0.68) was obtained. Excluding aspirates with low cellularity (less than 50,000 cells/ml), only one ER negative fine-needle aspirate was found among 47 ER positive surgical biopsies. A few ER positive aspirates corresponded to ER negative surgical biopsies possibly due to tumour heterogeneity or the fact that fine-needle aspiration sometimes may represent a better sampling technique than surgical biopsy.

Secretion of glucose in human parotid saliva after carbohydrate intake

The aims of the present investigation were, first, to follow the secretion of free glucose in parotid saliva in various subjects after a single oral intake of different carbohydrates, and second, to compare the salivary glucose concentration with the concentration in blood. Twenty healthy subjects, three women and 17 men, 20-35 yr of age, participated. They were asked not to eat or drink anything from 10 p.m. the night before the examination. 75 g of carbohydrate (glucose, fructose, or sucrose) dissolved in 300 ml water was ingested the next morning at 8 a.m. One experimental series with glucose was performed in triplicate in 10 of the subjects. Approximately 1.5 ml of citric acid-stimulated parotid saliva was collected before (0 min) and 15, 30, 45, 60, and 120 min after the intake. Salivary concentration of glucose was analyzed enzymatically. Most of the 0-min samples showed a variation in glucose concentration from 5 to 25 mumol/l. After the glucose, fructose, and sucrose intakes, the salivary glucose level increased about 2-4 times, especially in the 30-min samples. A large inter- as well as intra-individual variation was found both in the 0-min samples and in the samples collected after the different intakes. The correlation between the glucose concentration in saliva and blood was higher after than before the carbohydrate intakes.

Prognostic significance of estrogen and progesterone receptors in stage II breast cancer

Estrogen (ER) and progesterone receptors (PgR) were evaluated in samples from primary tumors in 539 patients with stage II breast cancer participating in a randomized multicenter controlled clinical trial on adjuvant therapy. At the cut-off points of 10 fmol ER/mg protein and 30 fmol PgR/mg protein, no significant difference in recurrence-free survival (RFS) existed between premenopausal patients with receptor-positive and negative tumors, respectively. After recurrence, premenopausal patients with receptor-positive tumors had a significant longer survival than patients with receptor-negative tumors. In postmenopausal patients not treated with adjuvant tamoxifen, no correlations between RFS and receptor status were found. Patients with ER+ tumors survived longer than patients with ER-tumors. In postmenopausal patients treated with adjuvant tamoxifen, highly significant differences in RFS and in survival were observed when receptor-positive patients were compared with receptor-negative patients. No differences in survival after recurrence were registered among these patients.

Early oral contraceptive use as a prognostic factor in breast cancer

The survival of 193 premenopausal breast cancer patients was investigated in relation to their history of early use of oral contraceptives. The women were born in 1939 or later and diagnosed in the southern health care region of Sweden. Women, who had started their oral contraceptive use (OC-use) before 20 years of age had a significantly lower survival rate as compared with those who had never used OC and late users (p = 0.02 and = 0.04 respectively, generalized Wilcoxon test). For women who started OC-use between 20 to 25 years of age, a tendency for a shorter survival was seen in comparison with women who had never used OC (p = 0.18). For all patients simultaneously, the relative risk adjusted for age at diagnosis increased for earlier OC-start. When only stages II and III were considered in a stratified multivariate model, a significantly elevated risk was seen for early users of OC irrespective of age or of adjuvant treatment given. The estrogen and progesterone receptor concentrations of the primary tumor were significantly lower among early users (p = 0.001 and p = 0.05 respectively).

Estramustine binding site in human breast cancer biopsy samples. Its relation to estrogen and progesterone receptor levels, age and menopausal status

Estramustine is a cytotoxic metabolite of estramustine phosphate (Estracyt), which is used in the treatment of prostatic carcinoma. An estramustine binding site (EMBS) at pH 4.8-4.9 was demonstrated in 74 of 306 (24%) breast cancer biopsy samples using isoelectric focusing in polyacrylamide gels. The presence of EMBS was significantly (P less than 0.001) correlated with negative or low estrogen and progesterone receptor values. EMBS positivity was found in 31% of the samples from pre- and perimenopausal patients and in 22% of the samples from postmenopausals. If patients were instead divided into different age groups, EMBS positivity was most frequent in samples from patients between 50 and 59 years of age (42%). With increasing age the percentage of EMBS positivity fell successively. For patients under 50 years, no difference with respect to EMBS positivity between age groups could be demonstrated. The possible value of EMBS determinations in breast cancer tissue specimens for the selection of those patients that will respond to Estracyt therapy should be evaluated.

Estrogen receptor and binding site for estramustine in metastatic malignant melanoma

Enzyme immuno assay (EIA) of estrogen receptor (ER) has confirmed the results of earlier investigations using steroid binding techniques, namely that ER is present at very low concentrations in samples from metastatic melanoma. Thirty-four of 61 samples (56%) were ER positive with EIA. The corresponding figures using isoelectric focusing (IF) for the steroid binding assay were 16 of these 61 samples (26%). The difference between the methods may be due to difficulties in the interpretation of analytical results for IF at low ER concentration levels or to interference from other 3H-estradiol binding components. Estramustine binding site (EMBS) has been found in samples from 15 of 77 patients (20%) with IF in polyacrylamide gels. Estramustine is, together with estramustine, the cytotoxic metabolite of estramustine phosphate (Estracyt). In analogy to the previously suggested therapeutic significance of estramustine binding protein in the treatment of prostatic cancer, the clinical importance of estramustine phosphate should also be studied in metastatic malignant melanoma in correlation with EMBS status.

Permanent alterations induced in plasma prolactin and estrogen receptor concentration in benign and malignant tissue of women who started oral contraceptive use at an early age

In 65 young women undergoing curettage for benign uterine disorders a significant relationship was found between early oral contraceptive use (starting age less than 25 years) and a high ratio of ln plasma prolactin versus ln estrogen receptor concentration of the uterine mucosae (p less than 0.047, Mann-Whitneys U-test). Year of birth, age at menarche, age at first full term pregnancy, parity, menstrual cycle phase and duration of oral contraceptive use could not explain the results. Because similar results have previously been found for breast cancer patients using plasma prolactin and breast tumour estrogen receptor concentration, the findings indicate that early oral contraceptive use permanently alters plasma prolactin levels and estrogen receptor concentration, both in benign uterine tissue and in malignant breast tumours.

A biological marker, strongly associated with early oral contraceptive use, for the selection of a high risk group for premenopausal breast cancer

In a population-based group of women, consecutively diagnosed, with premenopausal breast cancer there was a significant correlation between tumour size and plasma prolactin (r = 0.30; P less than 0.004). The concentration of estrogen receptor was negatively correlated to tumour size (r = 0.17; P less than 0.09). There were no substantial correlations between tumour size and progesterone receptor, plasma progesterone or estradiol. Adjustments for menstrual cycle day and age did not alter the above findings. The ratio of plasma prolactin and estrogen receptor was significantly greater (P less than 0.037) for the group of the patients that had started using oral contraceptives before the age of 20 as compared with the other patients. Consequently, the tumour size was significantly greater in the group of early users (P less than 0.003). The findings indicate that breast tumours developing in previous early users of oral contraceptives have a low estrogen receptor concentration, while these patients have higher plasma prolactin. The tumour size is greater in early users indicating a poorer prognosis than other women with breast cancer. As early use of oral contraceptives increases breast cancer risk and a high ratio of plasma prolactin and estrogen receptor concentration of the primary tumour characterize early oral contraceptive users the ratio may be a valuable marker for the breast cancer risk.

Enzyme immuno assay of the estrogen receptor in breast cancer biopsy samples. A comparison with isoelectric focusing

The estrogen receptor (ER) was measured by isoelectric focusing (IF) and enzyme immuno assay (EIA) in 127 breast cancer samples. When comparing the two techniques quantitatively, a very high correlation coefficient was obtained (rs = 0.98; p less than 0.001). ER recovery increased, however, by a mean factor of 2.5 when EIA was used instead of IF. This increase seemed to be influenced by the ER concentration level, being lower at higher levels. The difference between IF and EIA did not seem to be due to menopausal status. A possible field of application for EIA might be measurement of ER in samples from patients on tamoxifen therapy. In five out of nine such samples, a considerably higher measurable amount of ER was found with EIA than with IF. EIA was also found to be a simpler and less time-consuming method than IF. These advantages should, however, be weighed against the present higher costs.

Observations on wet weight, protein and DNA as reference for steroid receptors in malignant mammary tumours

Estradiol and progesterone receptors were recorded together with DNA and soluble protein per unit wet weight for 235 breast cancer samples. Receptor concentration values per wet weight showed the greatest range of variation. Receptor expressed per unit wet weight, DNA or protein showed good correlation (rs greater than 0.90). In selected cases different information on receptor concentration levels may be obtained depending on the reference parameter used. An overrepresentation was found of tumours with low receptor concentrations or receptors below the level of detection in a subgroup with a low DNA content, indicating the possibility of false low receptor values in this group. High ER and PgR contents were significantly related to high level of tissue DNA. Low or high content of protein was not associated directly with low or high receptor levels. In this respect DNA is superior to wet weight and protein as reference standards for receptor concentration. Further, DNA offers the additional possibility of a rough correction for non-epithelial components of the tumours. A critical dilution of receptors, as shown by low DNA content in some homogenates, was not apparent but cannot be excluded.

Antiestrogen binding sites in human breast cancer biopsies. Measurement ligand-specificity and affinity, and correlation to estrogen and progesterone receptors

Specific binding sites for the antiestrogen tamoxifen (AEBStot), as measured with the dextran-coated charcoal technique and Scatchard analysis, were quantitated in 43 of 44 breast cancer samples (41-2,100 fmol/mg protein). In this work, AEBStot has been defined as the sum of AEBSspec and estrogen receptor (ER), AEBSspec shows a very weak positive correlation with ER, and no correlation with progesterone receptor. Tamoxifen (TAM) has a lower affinity to ER compared with one of its main metabolites, 4-OH-TAM. This may be one reason why inhibition by excess estradiol on 3H-4-OH-TAM binding was better correlated with ER content in the same sample than if 3H-TAM was the radioactive ligand. It is therefore suggested that 3H-4-OH-TAM is a better choice than 3H-TAM for measuring AEBSspec alone. A possible role of AEBSspec for the clinical effects of TAM is discussed.

Estrogen and progesterone receptors in melanoma metastases with special reference to analytical methods and prognosis

Fifty-one tumor biopsies from 33 patients with metastatic melanoma were assessed for estrogen receptor (ER) content, and 46 of these for progesterone receptor (PgR) content in the cytoplasm. ER posivity (above 0.2 fmol/mg protein), as measured with isoelectric focusing on polyacrylamide gels, was found in 23 (70%) of the patients (range 0.2 - 14 fmol/mg protein). With a reference limit of 2 fmol ER/mg protein, 12 patients were positive (36%). PgR was analysed with the dextran coated charcoal technique and no sample demonstrated any positivity with certainty. The ER content was related to clinical prognostic factors without any significant correlation independent of reference limit used. A correlation to survival can not be excluded with ER values above 2 fmol/mg. Pertinent data are given regarding the technique used in comparison with others.