Expression and prognostic value of EGFR in invasive breast cancer

Epidermal growth factor receptor (EGFR) is a membrane receptor expressed in a variety of solid human cancers and directly related with poor prognosis. The objective of this work was to evaluate the EGFR content in breast carcinomas, its possible relationship with different clinical-pathological parameters, and its potential prognostic significance and predictive value. EGFR levels were examined by radioligand binding assays in 846 patients with invasive breast cancer. The median follow-up period was 50 months. There was a wide variability of EGFR levels among the studied tumors (0.01-403 fmol/mg protein). Statistical analysis showed that EGFR levels were significantly higher in younger patients (p=0.0001). EGFR were also notably higher in ER-negative or PgR-negative tumors than in ER-positive (p=0.0001) or PgR-positive tumors (p=0.001). In addition, the presence of high intratumoral EGFR levels (cut-off: 6 fmol/mg protein) was associated with both shorter relapse-free survival (p=0.04) and overall survival (p=0.01) in the group of patients as a whole, as well as with overall survival in the subgroup of patients without any type of systemic adjuvant treatment (p=0.02). However, EGFR levels did not achieve significance as independent prognostic factor in the multivariate analysis. There is a wide variability of intratumoral EGFR levels in breast carcinomas, and these protein levels correlated positively with a poor prognosis in the t univariate analysis. However, further studies are necessary in order to assess the possible clinical value of EGFR in combination with other essential components of the EGFR family network.     

Hormone receptor status of a contralateral breast cancer is independent of the receptor status of the first primary in patients not receiving adjuvant tamoxifen.

PURPOSE: To determine whether the hormone receptor status of the primary breast cancer (PBC) is predictive of the hormone receptor status of the subsequent contralateral breast cancer (CBC). PATIENTS AND METHODS: We identified patients in our database with known estrogen receptor (ER; n = 193) and/or progesterone receptor (PgR; n = 178) status in their PBC and in their subsequent CBC. One hundred twenty-six of these patients had received no adjuvant therapy, 34 had received adjuvant tamoxifen, and 33 had received adjuvant chemotherapy alone. The median interval between the first diagnosis of PBC and the development of the subsequent CBC was 3 years. ER and PgR assays were assessed biochemically in two central reference laboratories using identical quality-controlled ligand-binding methods. RESULTS: Among systemically untreated patients (n = 126), 88% of patients with ER-positive PBC and 75% of patients with ER-negative PBC developed an ER-positive CBC (P = .11). Among the tamoxifen-treated patients, those with an ER-positive PBC were almost equally likely to develop an ER-positive (47%) or ER-negative (53%) CBC (P = .99). PgR status was similar. In the untreated group (n = 112), 59% of patients with a PgR-positive PBC and 66% with a PgR-negative PBC developed a PgR-positive CBC (P = .48). Among tamoxifen-treated patients (n = 33), 50% of patients with a PgR-positive PBC versus 27% of patients with a PgR-negative PBC developed a PgR-positive CBC (P = .28). CONCLUSION: ER and PgR status of the primary tumor does not predict the hormone receptor status of the subsequent CBC in the absence of selective pressure of adjuvant therapy. Thus, other reasons should be considered to clarify the failure of tamoxifen to reduce the incidence of CBC in patients with a receptor-negative PBC.     

Comparative study of estrogen receptor assays between immunocytochemical assay using monoclonal antibody and the dextran- coated charcoal method

Estrogen receptor (ER) was measured by the estrogen receptor-immunocytochemical assay (ER-ICA) using monoclonal antibody in 36 mammary carcinomas. Simultaneously, ER and progesterone receptor (PgR) were measured by the dextran coated charcoal (DCC) method. In ER-ICA, tumor cells with estrogen receptors were histologically observed. The proportion of ER-positive tumor cells among tumor tissues and the levels of staining intensity were also examined. Results were compared to those obtained by the dextran coated charcoal (DCC) method. Tumors were evaluated as ER-ICA-positive when they contained more than 10% ER-positive cells. ER at a level of more than 5.0 fmol/mg protein was evaluated ER-positive and PgR at more than 5.0 fmol/mg protein as PgR-positive by the DCC method. Twenty-one out of 24 ER-ICA-positive tumors were ER-positive by the DCC method, and 11 out of 12 ER-ICA-negative tumors were ER-negative by the DCC method. Correlation of ER-ICA and ER by the DCC method was 88.9%. There were 11 PgR-positive tumors, and all were included among ER-ICA-positive tumors which had a high proportion of ER-positive cells and high staining intensities.     

Progesterone receptor status significantly improves outcome prediction over estrogen receptor status alone for adjuvant endocrine therapy in two large breast cancer databases.

PURPOSE: To determine whether progesterone receptor (PgR) status provides additional value to estrogen receptor (ER) status and improves prediction of benefit from endocrine treatment among patients with primary breast cancer. PATIENTS AND METHODS: Clinical outcomes of patients in two large databases were analyzed as a function of steroid receptor status. The first database (PP), contained 3,739 patients who did not receive any systemic adjuvant therapy and 1,688 patients who received adjuvant endocrine therapy but no chemotherapy. The second database (SPORE), contained 10,444 patients who received adjuvant endocrine therapy but no chemotherapy. Biochemical ER and PgR assays were identically performed in two different central laboratories. RESULTS: In univariate and multivariate analyses, the prognostic significance of PgR status among systemically untreated patients is modest. Among endocrine-treated patients, however, multivariate analyses, including lymph-node involvement, tumor size, and age, demonstrate that PgR status is independently associated with disease-free and overall survival. For recurrence, the reduction in relative risk (RR) was 25% for ER-positive/PgR-negative patients and 53% for ER-positive/PgR-positive patients, compared with ER-negative/PgR-negative patients (P <.0001, PP patients). Patients with ER-positive/PgR-negative tumors have a reduction in RR of death of 30% (SPORE patients) and 38% (PP patients), compared with patients with ER-negative/PgR-negative tumors (P <.0001). For ER-positive/PgR-positive tumors, the reduction of the risk of death was greater than 46% in SPORE patients and 58% in PP patients, indicating that ER-positive/PgR-positive patients derive more benefit from endocrine therapy (P <.0001). CONCLUSION: When accurately measured, PgR status is an independent predictive factor for benefit from adjuvant endocrine therapy. Therefore, PgR status should be taken into account when discussing RR reductions expected from endocrine treatment with individual patients.     

Correlation of lactogenic receptor concentration in human breast cancer with estrogen receptor concentration

The presence of receptors for lactogenic hormones in human breast cancer tissue has been documented previously, but the relationship between the expression of these receptors and estrogen receptor (ER) status has not been adequately studied. In this report, the specificity of 125I-human growth hormone (HGH) binding in both cultured human breast cancer cell lines and tumor biopsies was studied to establish that HGH was a suitable ligand for investigating lactogenic receptor concentration in these tissues. In addition, the relationship between specific binding of 125I-HGH and ER concentration in human breast cancer was investigated. Specific 125I-HGH binding to 14 breast cancer cell lines in long term culture and to membrane preparations (microsomal and plasma membrane fractions) from 31 breast cancer biopsy specimens was examined. Human prolactin and HGH were approximately equipotent in inhibiting binding of 125I-HGH to both cultured breast cancer cell lines and to membrane preparations from breast cancer biopsy specimens. Competitive inhibition experiments using lactogenic and somatogenic hormones established that the specificity of 125I-HGH binding to breast cancer biopsy material was similar to that of cultured breast cancer cell lines and similar to that reported for subprimate lactogenic receptors. Saturable, high-affinity (Ka = 0.53 to 2.33 nM-1), low-capacity (330 to 6560 sites/cell) growth hormone binding sites were found on each of the ER-positive cell lines, whereas no specific 125I-HGH binding to ER-negative cell monolayers was detected. When all cell lines were considered, a significant linear correlation (r = 0.745, p less than 0.001) between ER and lactogenic receptor concentrations was found. Significant specific 125I-HGH binding, greater than 1% of the total radioactivity added, was detected in 20 of 31 (65%) breast tumor biopsy specimens. The mean affinity and capacity of the lactogenic receptor as measured in 8 separate membrane preparations were Ka = 0.52 +/- 0.09 (S.E.) nM-1 and 255 +/- 85 fmol/mg protein. Membrane preparations from ER-negative tumors (less than 3 fmol ER/mg cytosol protein) bound significantly less 125I-HGH than did membrane preparations from ER-positive tumor biopsies (1.22 +/- 0.44 versus 3.21 +/- 0.56%, p less than 0.05). A significant linear correlation between specifically bound 125I-HGH and ER concentration (r = 0.412, p less than 0.02) was demonstrated in the 31 breast cancer biopsy specimens studied.(ABSTRACT TRUNCATED AT 400 WORDS)     

Benefit from adjuvant tamoxifen therapy in primary breast cancer patients according oestrogen receptor, progesterone receptor, EGF receptor and HER2 status.

BACKGROUND: Most women with oestrogen receptor (ER) positive primary breast cancer receive adjuvant tamoxifen after surgery. The measurement of tumour biomarkers should allow better selection of patients for such treatment or for therapies such as aromatase inhibitors. PATIENTS AND METHODS: Histopathological blocks of primary breast cancer patients who had been randomized to receive 2-years tamoxifen or no adjuvant therapy in two mature randomised clinical trials were retrieved. Immunohistochemical staining for ER, progesterone receptor (PgR), HER2 and epidermal growth factor receptor (EGFR) was undertaken. The primary endpoint was relapse free survival. RESULTS: 813 patients were included in the study. Benefit from tamoxifen was seen in ER-positive patients [Relative risk (rr) 0.77, ci 0.63-0.93]. ER-negative patients also showed a strong trend to benefit from tamoxifen (rr 0.73, ci 0.52-1.02) which was largely confined to the PgR-positive group. Amongst the ER-positive group, PgR-positive and PgR-negative patients showed similar benefit (rr 0.81; ci 0.65-1.02 and 0.70; ci 0.49-0.99, respectively). Patients positive for HER2 did not benefit significantly (rr 1.14; ci 0.75-1.73) but this group was small. CONCLUSIONS: Measurement of PgR status in ER-negative patients defines a group of patients that benefit from tamoxifen but would be excluded from tamoxifen therapy on the basis of ER status alone. The data are consistent with HER2 positive tumours being resistant to tamoxifen.     

Hormone receptors and disease-free survival in breast cancer: impact of increasing threshold levels

Laboratory data from Milan and Houston were evaluated to determine the extent to which the distribution of estrogen receptor (ER) and progesterone receptor (PgR) has changed with time. Results from over 11,500 ER and over 8,200 PgR determinations (6,194 ER and 3,127 PgR from Milan) were analyzed. All assays in Milan were performed by a dextran-coated charcoal method and in Houston by a sucrose density-gradient method. The data demonstrate a time-dependent, upward drift in the amount of ER and PgR detected, with the effect most pronounced at the lower end of the distribution curves. We attribute this change to optimization of all facets of the receptor assay procedures (tissue harvesting and storage) as well as to a change in breast cancer biology. These results suggest that studies correlating certain biological parameters with receptor status (whether using qualitative or quantitative scales) need to be re-examined. For example, a population of 349 node-negative patients who did not receive any adjuvant treatment was studied in Milan to determine any association between disease-free survival (DFS) and receptor status. If the "historical" threshold values (10 fmol/mg protein) were used to determine receptor status, no significant difference in DFS at 5 years was detected. Even the combination of ER and PgR did not improve the predictive power of receptor status. In the premenopausal subgroup, ER status did predict the 5-year DFS. However, if the threshold value for PgR was adjusted to 25 fmol/mg protein, patients with ER-positive, PgR-positive tumors had significantly better 5-year DFS than patients with ER-negative, PgR-negative tumors. In addition, PgR status alone was associated with significantly improved 3-year DFS if the subgroups of PgR less than 5 fmol/mg protein and PgR greater than 100 fmol/mg protein were compared. We conclude from these data that: 1) historical threshold values for receptor positivity should be re-examined in all laboratories; 2) studies involving receptor results determined over an extended period of time should attempt to "normalize" these results; and 3) the quantitative assessment of receptor status should be used whenever possible.     

Distribution of estrogen and progesterone receptors in primary tumor and lymph nodes in individual patients with breast cancer

Primary breast cancer tissue and lymph nodes were obtained from 48 patients. Estrogen receptors (ER) and progesterone receptors (PgR) were determined by a dextran-coated charcoal assay. ER were present in 72.9% of the primary tumors and in 62.4% of the malignant lymph nodes, whereas PgR were present in 73.0% and 50.0% of the cases, respectively. The primary tumor and the corresponding malignant lymph nodes showed an identical ER and PgR status, i.e., both tumor sites were receptor positive or both receptor negative in 89.6% and 77.1%, respectively. However, 10.4% of the patients had ER-positive tumors but ER-negative lymph nodes and 22.9% had PgR-positive primaries with PgR-negative lymph nodes. No receptor-positive lymph nodes showed a combination with receptor-negative primary tumor. This preliminary data shows that receptor-positive malignant lymph nodes mostly display the same receptor status as the corresponding primary tumor, whereas receptor-negative lymph nodes may have a receptor-positive primary tumor.     

Simultaneous estimation of epidermal growth factor receptors and steroid receptors in a series of 136 resectable primary breast tumors

Human breast cancer cell lines, as well as human breast cancer biopsies, possess specific high-affinity epidermal growth factor receptors (EGF-r). However, reports on the presence of EGF-r in human breast cancer biopsies are still controversial, especially concerning the relationship between EGF-r and other biological variables whose prognostic relevance is well known, such as the estrogen (ER) and progesterone (PgR) receptors. In the present study, the EGF-r content was estimated in a series of 136 unselected breast cancer primaries along with cytoplasmic (ERc) and nuclear (ERn) ER and cytoplasmic PgR. EGF-binding activity consisted of a single class of high-affinity binding sites (Kd = 0.55 nM) and ranged from 0 to 275 fmol/mg protein. We observed a strong inverse association between EGF-r and ERc (p less than 0.001); in fact, about two thirds of the tumors were ERc-positive/EGF-r-negative or ERc-negative/EGF-r-positive. The same type of association was found between EGF-r and either ERn or PgR. Kendall's rank correlation test confirmed that the EGF-r concentrations were correlated with the levels of ERc (tau = -0.291, p less than 0.0001), ERn (tau = -0.27, p less than 0.0005) and PgR (tau = -0.162, p less than 0.01). The EGF-r content was significantly higher (p less than 0.0001) in the ERc-negative tumors (72.6 +/- 54.4 fmol/mg protein) as compared to the ERc-positive ones (33.0 +/- 37.4 fmol/mg protein). Similarly, the subset of PgR-positive tumors was characterized by lower EGF-r mean concentrations when compared to PgR-negative cases (35.4 +/- 54.4 vs. 63.8 +/- 54.4 fmol/mg protein). These results confirm the previously described inverse relationship between EGF-r and steroid receptors. Moreover, they suggest the existence of an interaction between steroid hormones and EGF and support the need for further studies to better understand their respective roles in modulating breast cancer growth.     

Tumor-proliferative activity, progesterone receptor status, estrogen receptor level, and clinical outcome of estrogen receptor-positive advanced breast cancer

The relations among pretreatment tumor-proliferative activity, progesterone receptor (PgR) status, estrogen receptor (ER) level, and clinical outcome were analyzed in a series of 45 ER-positive advanced breast cancer postmenopausal women treated with tamoxifen (20 mg/day) until disease progression. Tritiated thymidine ([3H]dThd) Labeling Index (LI) by autoradiographic assay was utilized for proliferative activity analysis, whereas the dextran-coated charcoal method was used for ER and PgR evaluation (cutoff value, 10 fmol/mg of protein cytosol). The median [3H]dThd LI value was 1.8%; 73% of cases were PgR positive, and 53% were highly ER positive (greater than 100 fmol/mg of protein cytosol). Clinical responses were more frequently observed in slowly than in quickly proliferating tumors (86% versus 60%; P less than 0.05) but were similar for PgR-positive and -negative cases, as well as for those with high and low ER positivity. Only [3H]dThd LI was found to individualize patients with different survival rates (at 40 mo of follow-up, 78% versus 40% in slowly and quickly proliferating tumors, respectively). The [3H]dThd LI, monitored in ten patients by a second tumor biopsy after 14 days of tamoxifen therapy, was found to have a significantly lower median value (P = 0.03). These data indicate that pretreatment [3H]dThd LI provides information, which is not available in a study of PgR and ER status, on the clinical outcome of ER-positive advanced breast cancer patients treated by hormone therapy.     

Association of serum estrone levels with estrogen receptor-positive breast cancer risk in postmenopausal Japanese women.

PURPOSE: Several reports have demonstrated the association between high serum estrogens levels and breast cancer risk in postmenopausal women. It is hypothesized that breast cancers arising in postmenopausal women with high serum estrogens levels are more likely to be estrogen receptor (ER)-positive. Thus, we have investigated whether or not high serum estrone (E(1)) levels are associated with ER-positive breast cancer risk in postmenopausal women. EXPERIMENTAL DESIGN: A case-control study was conducted on 71 cases (postmenopausal breast cancer patients) and 73 controls (postmenopausal healthy women). Serum E(1) levels were examined in their association with breast cancer risk after adjustment for the various epidemiological risk factors. In addition, clinicopathological characteristics of breast cancers arising in the women with high E(1) levels were investigated. RESULTS: Women in the high tertile of E(1) levels had a significantly (P < 0.01) increased risk of breast cancer as compared with women in the low tertile [odds ratio (OR), 4.14; 95% confidence interval (CI), 1.44-11.87]. Subset analysis according to the ER status showed that women in the high tertile of E(1) levels had a significantly increased risk for ER-positive breast cancer (OR, 23.79; 95% CI, 3.50-161.59) but not for ER-negative breast cancer (OR, 1.45; 95% CI, 0.41-5.15) as compared with women in the low tertile. Tumor size and lymph node status were not significantly different between women in the high tertile and those in the intermediate and low tertiles. But the frequency of low-histological-grade tumors and ER-positive tumors (88 and 67%, respectively) showed a greater trend toward an increase (P = 0.06 and P = 0.07, respectively) in women in the high tertile than those (69 and 46%, respectively) in the intermediate and low tertiles. In addition, ER levels in ER-positive tumors were significantly (P < 0.05) higher in women in the high tertile (245.3 +/- 37.1 fmol/mg protein) than those in the intermediate and low tertiles (134.0 +/- 31.3 fmol/mg protein). CONCLUSIONS: Postmenopausal women with high serum E(1) levels have a significantly increased risk for ER-positive, but not ER-negative, breast cancer. Breast cancers arising in women with high E(1) levels show a high ER positivity as well as high ER content. Measurement of serum E(1) levels would be clinically useful in the selection of postmenopausal women who can benefit from prophylactic use of tamoxifen because tamoxifen can prevent ER-positive, but not ER-negative, breast cancer.     

Epidermal growth factor receptor levels are lower in carcinomatous than in normal colorectal tissue.

A series of 24 paired samples of colorectal carcinoma and the respective normal colorectal mucosa were analysed for Epidermal Growth Factor Receptor (EGFR) content by means of a standardised ligand binding assay. We, for the first time, found that EGFR levels are statistically significantly higher in normal colorectal mucosa biopsy samples than they are in colorectal carcinoma biopsy samples, the median EGFR levels being 77.5 fmol mg-1 of membrane protein (range 35-239), against 46 fmol mg-1 of membrane protein (range 22-81), respectively, P less than 0.001. In addition, we found that there are significant regional differences in EGFR expression in the normal human colon mucosa. The EGFR levels were significantly higher in samples from the proximal part of the colon than they were in samples from the distal part, the median EGFR levels being 124 fmol mg-1 of membrane protein (range 70-239) vs 55 fmol mg-1 membrane protein (range 35-156), P less than 0.05. The EGFR levels of the colorectal carcinoma samples did not show any regional variation.     

Correlation between nuclear cytomorphometric parameters and estrogen receptor levels in breast cancer

The authors studied the relationships existing between various cytomorphonuclear parameters recorded on 25 primary breast cancers and their estrogen receptor (ER) content. Cell image analyses of Feulgen-stained imprint smears, allowing determination of morphologic, densitometric, as well as textural parameters, were assessed by using the SAMBA 200 system (TITN, France). The ER levels were measured by the conventional dextran-coated charcoal assay. The authors then divided the 25 cancers into three categories: (1) "ER-negative or poorly positive tumors," i.e., those having less than 50 fmol ER/mg protein; (2) "ER-positive tumors," i.e., those containing between 50 and 150 fmol ER/mg protein; and (3) "ER highly positive tumors," i.e., those having more than 150 fmol ER/mg protein. The authors' results show that ER-negative or poorly positive breast cancers possess cells with bigger nuclei and higher DNA content, related to higher proliferation index than ER-rich tumors. Furthermore, the chromatin pattern of cells from ER-negative or poorly positive breast cancers is significantly more condensed than the thinly textured chromatin of ER highly positive tumors. Cell image analysis of Feulgen-stained imprints is proposed as an additional tool for grading malignancy.     

Prognostic value of hormone receptors in breast cancer

The aim of this study was to establish the role of estrogen receptor (ER) and progesterone receptor (PgR) as prognostic indicators for early recurrence and survival. In all, among breast cancer patients, 166 patients who had undergone radical or extended radical mastectomy were studied. These patients were treated with adjuvant chemotherapy alone for 2-3 years after surgery. No patients had adjuvant endocrine therapy. Local recurrence and/or distant metastases were treated by endocrine therapy and/or chemotherapy. The relapse-free interval was not different between the ER-positive and ER-negative patients. The postrelapse survival curve was significantly different between the two groups. There was no significant difference in the relapse-free interval and the postrelapse survival curve between the PgR-positive and PgR-negative patients. These results suggest that ER is a good predictor of the response to endocrine therapy given after relapse, but not of early recurrence.     

Observations on the presence of E domain variants of estrogen receptor-alpha in the breast tumors

BACKGROUND AND OBJECTIVES: Estrogen receptor-alpha (ER-alpha) that exists as multiple splice variants, has been widely used as a prognostic marker in the management of breast cancer. Here we have analyzed the hormone binding E domain splice variants of ER-alpha in the breast tumors with reference to the immunoreactive receptor. METHODS: Thirty breast cancer patients undergoing surgery at the All India Institute of Medical Sciences, New Delhi, were analyzed for the splice variants of E domain by RT-PCR. The ER level was determined by ELISA and the samples were considered positive if the receptor levels were >or= 15 fmol/mg protein. RESULTS: Our results show that exon 4 and 5 deletions were prevalent in both ER-positive and ER-negative categories. While most ER-positive cases expressed wild-type (wt) exon 6 + 7, nearly 40% of ER-negative cases showed deletion of exon 6 + 7. Therefore, deletion of exon 6 + 7 or masking of epitopes could lead to underestimation of ER by ELISA. All the metastasis and recurrence cases had undetectable levels of ER. A significant number of node-positive cases expressed immunoreactive ER and wt exon 6 + 7 (r = 0.509, P < 0.37). CONCLUSIONS: Estimation of ER levels combined with composite analysis of ER variants may be a better prognostic marker for breast cancer.     

Clinical significance of the expression of epidermal growth factor and its receptor in esophageal cancer

The epidermal growth factor receptor (EGFR) level in 56 esophageal cancer tissues was measured by 125I-EGF binding assay to elucidate its role in tumor progression. The survival rate of patients with high EGFR level (more than 50 fmol/mg protein) was significantly lower than that of patients with low EGFR level (less than 50 fmol/mg protein, P less than 0.01), although a correlation between EGFR level and the pathologic findings was not observed. The expression of EGF was examined immunohistochemically using anti-EGF monoclonal antibody in 100 esophageal cancer tissues; EGF-positive tumor cells were detected in 92.0%. The immunoreactivity of EGF was classified arbitrarily into four grades according to the number of stained tumor cells. The expression of EGF significantly correlated with the differentiation of esophageal squamous cell carcinoma (P less than 0.01, by chi-square test). The survival rate of patients with high EGF immunoreactivity (Grade 2 or 3) was much lower than in those with lower grade (0 or 1) tumors, (P less than 0.01). Patients with both high EGFR level and EGF immunoreactivity had a much worse prognosis than if both were low. Furthermore, the mitotic index was higher in groups with both high EGFR and EGF than if both were low (16.39 +/- 5.35 versus 6.90 +/- 3.31). These results suggest that EGF and EGFR in the autocrine system may play an important role in tumor progression in esophageal cancer and their expression could be of prognostic significance.     

Epidermal growth factor receptor in human breast cancer

For the purpose of demonstrating the relationship between epidermal growth factor receptor (EGFR) content in the tumor and histopathologic characteristics, 45 women with breast cancer who underwent mastectomy were analyzed. EGFR content was measured by competitive binding assay using 125I, while EGFR was detected by immunocytochemical staining. Tumors with more than 1 fmol/mg protein EGFR were defined as positive, and a good correlation between competitive binding assay and staining was observed. Seventeen of them (37.8%) had EGFR-positive tumors. Eight of the 17 EGFR-positive tumors (47.1%) were positive for estrogen receptor (ER), whereas 24 of the 28 EGFR-negative tumors (85.7%) were ER-positive. This inverse relation was statistically significant (chi 2; p less than 0.05). Twelve of the 17 EGFR-positive cases (70.6%) had axillary node involvements, against 11 of the 28 (39.3%) in the EGFR-negative cases. There was no difference in the size of primary tumor between the two groups. These results suggested that EGFR-positive tumors have more malignant potency than EGFR-negative tumors. In 8 cases, EGFR content in metastatic axillary nodes was compared with that in primary tumors. More EGFR content indicated in metastatic axillary nodes than in primary tumors without significant difference.     

Immunoenzymetric assay of epidermal growth factor receptor. Application to breast tumor samples

An immunoenzymetric assay (IEMA) for the human epidermal growth factor receptor (EGFR) solubilized with nonionic detergent has been developed using two commercially available monoclonal antibodies (MoAb) and tested on breast tumor samples. The first MoAb (R1), immunoadsorbed on a solid phase, is used to immobilize solubilized EGFR. A second MoAb (528) binds to the immobilized EGFR and is revealed with o-phenylenediamine by a peroxidase-linked goat antimouse IgG2a. The detection limit is 2.5 fmol/ml, corresponding to 1-2.5 fmol/mg membrane protein which allows a determination of EGFR from as low as 100-200 micrograms of membrane proteins. The IEMA was linear for serial sample dilutions in a large range of EGFR concentrations. The recovery of increasing quantities of EGFR added to clinical samples ranged from 82 to 107%. We found a high reproducibility (r = 0.97) between two successive assays of 36 breast tumor samples. The EGFR content measured by this method in 50 breast tumor samples correlated (r = 0.95) with the values obtained by a radioligand assay on crude membrane preparations. This sensitive, accurate, reproducible, time and tissue quantity efficient IEMA appears suitable for biological and clinical studies of the role of EGFR in malignant pathology.     

Relative effect of steroid hormone receptors on the prognosis of patients with operable breast cancer. A univariate and multivariate analysis of 3089 Japanese patients with breast cancer from the Study Group for the Japanese Breast Cancer Society on Hormone Receptors and Prognosis in Breast Cancer.

In a retrospective multicenter study to investigate the correlation between estrogen (ER) and/or progesterone receptors (PgR) in primary breast cancer with patient prognosis, 3118 patients with operable breast cancer (International Union Against Cancer Stages I, II, and III) were investigated from ten hospitals in Japan who underwent surgery from October 1972 to December 1982; 3089 were evaluable. The ER-positive and PgR-positive cancers were found in 56% and 34% of patients, respectively. The positivities decreased as the tumor size increased but were independent on lymph node metastasis. There were no significant differences in relapse-free survival (RFS) in relation to receptor status (median follow-up, 89 months [ER], 84 months [PgR]). However, in patients with four or more positive nodes, those with PgR-positive cancer had a longer RFS. The patients with ER-positive cancer survived significantly longer than ER-negative ones, with the greatest difference seen in those with four or more positive nodes. There was a significantly longer postrelapse survival (PRS) for patients with ER-positive cancer because of the different distribution of the major metastasis and better responses to first-line and subsequent treatments. Cox's multivariate analysis showed that overall survival but not PRS was affected by ER (and more weakly by PgR) because of the longer PRS in patients with ER-positive cancer.     

Estrogen and progesterone receptors in the normal female breast

We have studied estrogen receptor (ER) and progesterone receptor (PR) in normal breast by immunocytochemistry using tissue biopsies and fine needle aspirates (FNA) and, in the case of ER, by enzyme immunoassay. For ER we found a high degree of reproducibility for biopsies taken from the upper outer quadrant: FNA, r = 0.56 (P less than 0.002); tissue section immunocytochemistry, r = 0.89 (P less than 0.0001); and enzyme immunoassay, r = 0.76 (P less than 0.0001). For PR, FNA (r = 0.56, P less than 0.002) and tissue section (r = 0.97, P less than 0.0001) were also found to be reproducible techniques. Using enzyme immunoassay, we were able to measure ER accurately in normal breast tissue. In 59 samples we found a range of 0-37 fmol/mg cytosol protein (mean, 4 fmol/mg). In an age-matched group of 126 women with breast cancer, we found a significantly higher ER [range, 0-139 fmol/mg; mean, 37 fmol/mg (P less than 0.001)]. We then analyzed the ER and PR content of FNAs obtained from the upper outer quadrant of the normal breast in 143 normal women. We found that in only 23 of 143 samples (16%) were greater than or equal to 50% epithelial cells stained. There was a relationship between ER and PR (P = 0.03) and a higher ER content in European women than in non-European women (P less than 0.03). The PR content was related to high body mass index (P less than 0.02) and family history of breast cancer (P = 0.04). Samples tended to be more frequently ER positive by FNA if taken in the follicular phase of the menstrual cycle. We conclude that, although the levels of ER and PR are low in normal breast, they can be accurately measured. There is significant variation of ER and PR with several clinical parameters.