Measurement of estrogen and progesterone receptors in human breast tumors: enzyme immunoassay versus binding assay

To Evaluate the Applicability of Parameters of Cytological Grading Systems on Aspirates of Breast Carcinoma

Background:

Fine-needle aspiration cytology (FNAC) is still an important first line diagnostic procedure in developing countries. FNAC of breast lesions is quite specific and sensitive investigation and the results are comparable to histopathology.

Aim:

To evaluate applicability of parameters of different cytological grading (CG) systems, for aspirates of breast cancers, and its correlation with histopathology grading parameters.

Materials and Methods:

A cross-sectional observational study was carried out on 30 female patients with ductal carcinoma breast, diagnosed on FNAC and subsequently confirmed histopathologically. The cytological smears were graded using six different cytological parameters/criteria described by Robinson et al. (Robinson grading system) and modified Scarff-Bloom-Richardson (SBR) grading system considering three parameters. The results of cytological grade (CG) were compared with parameters of gold standard modified SBR histological grading (HG) system.

Results:

Important influential cytological parameters to predict final RBS cytological score came out to be chromatin, nucleoli, nuclear size, cell uniformity, and cell dissociation with statistically significant P value (0.0001) except for mitotic count. The important influential predictor of final SBR histological score is nuclear pleomorphism.

Conclusion:

SBR HG has good correlation with both RBS and SBR CG systems. The cytological nuclear grade provides important prognostic information which is very sensitive and equally specific hence should be done in breast aspirates and is now replaced by Core Needle biopsy. In developing country like India FNAC of breast aspirates still holds diagnostic value in the classification of breast lesions as compared to core guided image biopsy.

Classical and Novel Prognostic Markers for Breast Cancer and their Clinical Significance

The use of biomarkers ensures breast cancer patients receive optimal treatment. Established biomarkers such as estrogen receptor (ER) and progesterone receptor (PR) have been playing significant roles in the selection and management of patients for endocrine therapy. HER2 is a strong predictor of response to trastuzumab. Recently, the roles of ER as a negative and HER2 as a positive indicator for chemotherapy have been established. Ki67 has traditionally been recognized as a poor prognostic factor, but recent studies suggest that measurement of Ki67-positive cells during treatment will more effectively predict treatment efficacy for both anti-hormonal and chemotherapy. p53 mutations are found in 20–35% of human breast cancers and are associated with aggressive disease with poor clinical outcome when the DNA-binding domain is mutated. The utility of cyclin D1 as a predictor of breast cancer prognosis is controversial, but cyclin D1b overexpression is associated with poor prognosis. Likewise, overexpression of the low molecular weight form of cyclin E1 protein predicts poor prognosis. Breast cancers from BRCA1/2 carriers often show high nuclear grades, negativity to ER/PR/HER2, and p53 mutations, and thus, are associated with poor prognosis. The prognostic values of other molecular markers, such as p14^ARF, TBX2/3, VEGF in breast cancer are also discussed. Careful evaluation of these biomarkers with current treatment modality is required to determine whether their measurement or monitoring offer significant clinical benefits.

Prognostic molecular markers in early breast cancer

A multitude of molecules involved in breast cancer biology have been studied as potential prognostic markers. In the present review we discuss the role of established molecular markers, as well as potential applications of emerging new technologies. Those molecules used routinely to make treatment decisions in patients with early-stage breast cancer include markers of proliferation (e.g. Ki-67), hormone receptors, and the human epidermal growth factor receptor 2. Tumor markers shown to have prognostic value but not used routinely include cyclin D1 and cyclin E, urokinase-like plasminogen activator/plasminogen activator inhibitor, and cathepsin D. The level of evidence for other molecular markers is lower, in part because most studies were retrospective and not adequately powered, making their findings unsuitable for choosing treatments for individual patients. Gene microarrays have been successfully used to classify breast cancers into subtypes with specific gene expression profiles and to evaluate prognosis. RT-PCR has also been used to evaluate expression of multiple genes in archival tissue. Proteomics technologies are in development.

Estrogen receptors and distinct patterns of breast cancer relapse

BACKGROUND

We conducted an analysis of prospectively collected data to compare the clinical behavior of ER-negative versus ER-positive tumors with respect to rates and sites of recurrence.

METHODS

A total of 647 patients with operable stage II or III breast cancer were enrolled in two consecutive adjuvant therapy protocols conducted between 1980 and 1986. The correlations between ER status and time to first recurrence, site of first recurrence, and time to breast cancer death were assessed on 558 (86%) patients with available ER status data using hazard function and hazard ratio function analysis.

RESULTS

The rates of recurrence were significantly higher in patients with ER-negative status for the first two years of follow-up, but not thereafter. Similar results were observed for breast cancer death, and these results held up after adjustment for differences in treatment, age, menopausal status, and tumor burden. When the site of first recurrence was studied, ER-negative status was associated with a significantly higher rate of tumor recurrence in the viscera and soft tissues, while ER-positive status was associated with significantly higher rates of tumor recurrence involving bone.

CONCLUSIONS

The clinical behavior of ER-positive tumors is different from ER-negative cancer. ER status had a pronounced effect on the rates and sites of recurrence. Furthermore, this apparent association diminished over the follow-up period. Recurrence rates were significantly higher in patients with ER-negative status for the first two years of follow-up, but not thereafter.

Molecular prognostic factors for breast cancer metastasis and survival

The biological characteristics of the tumor are used to estimate prognosis and select appropriate systemic therapy for patients with early-stage breast cancer. Well-established molecular prognostic factors include the estrogen and progesterone receptors, proliferation markers, and the HER2 gene. Novel tumor markers with potential clinical utility include molecules involved in cell transformation, invasion, and metastases. We review the available data supporting the utility of established prognostic and predictive molecular factors, and discuss challenges for integrating novel molecular markers into clinical practice.

Type 1 protein tyrosine kinases in Chinese breast carcinomas: a clinicopathologic study

Immunostaining for epidermal growth factor receptor (EGFR), c-erbB-2, c-erbB-3, c-erbB-4, ER, and PR was performed in 107 cases of primary breast carcinomas from Anyang, China. The expression rates of EGFR, c-erbB-2, c-erbB-3 and c-erbB-4 in this series were 43.9%, 36%, 27%, and 45.8%, respectively, and a stronger c-erbB-4 staining of "normal" glandular structures inside tumors and in the vicinity of tumor clusters was confirmed. Larger tumor size, lymph node metastases, and higher histologic grade in invasive ductal carcinomas were shown to be statistically valuable negative prognostic factors, and c-erbB-2 expression was also weakly associated with a poor prognosis no matter what the nodal status. The expressions of c-erbB-4 and ER in invasive ductal carcinomas were inversely associated with histologic grade of the tumors. Associations between the expression of c-erbB-4 and ER (p = 0.001) and the expression of ER and PR study (p = 0.004) were found in the present study. No significant associations between the expressions of EGFR, c-erbB-3, c-erbB-4, ER, and PR and overall survival were detected. The expression of c-erbB-4 in the node negative group was, however, associated with a better prognosis, indicating a different role of c-erbB-4 protein in breast tumor development than other EGFR family members have. Int J Surg Pathol 9(3):177-187, 2001

Molecular markers for predicting response to tamoxifen in breast cancer patients

Tamoxifen is one of the most effective treatments for breast cancer. Standard practice is to select patients who are likely to respond to this therapy through the evaluation of estrogen receptor (ER) and progesterone receptor (PR) in the primary tumor tissue. Over the past 25 yr that physicians have been using ER determination to guide tamoxifen use, numerous studies have demonstrated that this molecular marker is useful in predicting benefit from tamoxifen. ER has been analyzed for many years using ligand-binding assays. However, current practice involves the use of immunohistochemical-based assays to detect ERalpha Immunohistochemistry (IHC) has several advantages. For example, IHC evaluates tumor cell heterogeneity, can be used to study small samples, is less expensive, and allows direct correlation with multiple histopathological tumor features and other molecular markers. PR, an estrogen-responsive protein, can also be useful in predicting response to tamoxifen in specific clinical situations. In recent years, several other markers of tamoxifen response have been examined, including: pS2 (another estrogen-regulated protein), heat-shock proteins 27 and 70, bcl-2 protein, c-erbB-2 (HER-2/neu) oncoprotein, and mutated p53 tumor suppressor protein. In this article, we present an analysis of the data on these new molecular markers. Overall, from numerous studies, the data indicate that in addition to ERalpha bcl-2 is a potential candidate to help further improve our ability to predict response to tamoxifen. ER and bcl-2 are the most useful molecular markers to better identify breast cancer patients who will respond to tamoxifen and who will have prolonged survival.

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.

Steroid receptor measurement in breast cancers: comparison between ligand binding and enzyme-immunoassay in cytosolic and nuclear extracts

We have analysed cytoplasmic and nuclear extracts of breast-cancer tissue from a total of 799 patients, measuring both oestrogen and progesterone receptors (ER, PR) using either the ligand binding assay (LBA) or the enzyme immunoassay technique (EIA). Mean and median receptor levels were much lower than those widely reported by others. For ER, this may in part be a consequence of the younger median age of the patient group. The frequency of positivity, using consensus cut-off values for clinical evaluation, was also lower than that reported by the EORTC Receptor Study Group. Although the measurements comparing the 2 methods were statistically correlated in terms of positivity, based on the above criteria for clinical assessment, concordance was considered to be relatively poor, particularly for ER when assayed in the same samples by the 2 methods. In cytosolic but not nuclear extracts, the LBA method gave a higher median value for ER than the EIA (except in the group that had EIA values greater than 15 fmol/mg protein); for PR, median values were higher with EIA in both cell fractions. There was an excellent correlation between receptor amounts in cytosolic and nuclear extracts for both ER and PR using the EIA; this was significantly better than with LBA. We also observed a correlation between ER and PR in both cytosolic and nuclear fractions which was most pronounced when the analysis was done by EIA. The amounts of ER in the cytosolic fraction were also correlated with the those of PR in the nuclear fraction and ER in the nuclear fraction with PR in the cytosolic fraction, but only when the EIA method was used. We conclude that the EIA method appears to be more sensitive and gives biologically more reliable results. However, the disagreement between the methods may be due to legitimate recognition of altered forms of the receptor and may be of biological significance. Although the presence of receptor in the cytosolic fraction is artifactual, its measurement by EIA does parallel the amounts of nuclear receptor, which may be a more relevant biological parameter.

Comparison of estrogen receptor determinations by a biochemical ligand-binding assay and immunohistochemical staining with monoclonal antibody ER1D5 in females with lymph node positive breast carcinoma entered on two prospective clinical trials

BACKGROUND

The measurement of estrogen receptors (ER) in breast cancer specimens has traditionally been assessed with a dextran-coated charcoal assay (DCCA). More recently the immunohistochemical staining (IHC) method has gained increasing popularity because of its ability to use fixed tissue, assess needle biopsies, and reduce cost. Controversy exists over the accuracy of IHC compared with that of DCCA in determining ER. We compared these two techniques using tumor tissue obtained from a large group of females with lymph node positive breast carcinoma with long term follow-up.

METHODS

Breast carcinoma tissue was obtained from a large group of females with node positive breast carcinoma participating in two adjuvant chemotherapy trials. ER was determined by the traditional DCCA method and by IHC using the ER1D5 antibody. Disease free survival (DFS) and overall survival (OS) were assessed by each of these methods.

RESULTS

ER status was determined by DCCA and IHC in tumor tissue obtained from 316 females. A concordance of 79% was observed for the determination of ER-positive tumors. Of the discordant results, the majority of DCCA-negative, IHC-positive tumors could be explained by a low level of DCCA positivity (< 10 fmol) or IHC staining of nonmalignant cells. A much higher rate of discordant results was observed in premenopausal females. Of the DCCA-negative, IHC-positive patients 97% were premenopausal and of the DCCA-positive, IHC-negative patients 79% were premenopausal. ER by DCC appears to perform better than ER by IHC as a prognostic factor in terms of DFS and OS.

CONCLUSIONS

When compared with DCCA, IHC with monoclonal antibody ER1D5 appears to be a reasonable substitute for the determination of ER. Although DCCA appeared to perform better as a determinant of prognosis, ER detection is used primarily for deciding on hormonal therapy. Review of discordant cases indicates IHC may more accurately reflect the ER status of malignant cells in some patients. Attention must be paid to quality control considerations in performance of IHC staining.

Relationship between low estrogen receptor values and other prognostic factors in primary breast tumors

BACKGROUND

The current study compared the immunocytochemical expression of estrogen (ER) and progesterone (PgR) receptors by malignant breast cells to the hormone receptor concentrations reported from radioligand assays. These values were examined in relation to DNA ploidy and the fraction of cells in S phase.

METHODS

ER and PgR concentrations, DNA ploidy, and S-phase fractions were measured by standard techniques with 124 samples of invasive ductal carcinoma. Suspensions of tumor cells were examined by immunocytochemical assay (ICA) for the percentages of ER and PgR positive cells.

RESULTS

Twenty-six of the 38 tumors from patients 50 years of age or younger were classified as high S-phase fraction, and 28 tumors had aneuploid levels of DNA. The 20 ER positive tumors each contained less than 100 fmol/mg. Thirty-nine of the 86 tumors from patients older than 50 years were classified as high S phase, and 41 were aneuploid. Sixty-five samples were considered ER positive by radioligand assay. ICA showed that tumors in either age group with less than 40 fmol/mg did not contain ER positive cells. The proportion of samples with PgR levels between 10 and 100 fmol/mg was small, and fewer PgR positive tumors were categorized as negative when examined by ICA for receptor containing cells. The reclassification of the hormone receptor status of a tumor based on ICA appeared to be independent of S-phase and ploidy values.

CONCLUSIONS

Tumors that are classified as ER or PgR positive based on accepted cutoff values for radioligand assays may actually be receptor negative because the tumors do not appear to contain receptor positive cells.

Imaging, biodistribution and therapy potential of halogenated tamoxifen analogues

Tamoxifen binds to estrogen receptors (ERs) and prevents breast cancer cell proliferation. This study is aimed at developing a ligand for imaging ER (+) breast tumors by positron emission tomography (PET) or single photon emission computed tomography (SPECT). [18F]-Labeled tamoxifen analogue ([18F]FTX) was prepared in 30-40% yield and [131I]-labeled tamoxifen analogue ([131I]ITX) was prepared in 20-25% yield. In mammary tumor-bearing rats, the biodistribution of [18F]FTX at 2 h showed a tumor uptake value (% injected dose/gram tissue) of 0.41 +/- 0.07; when rats were pretreated with diethylstilbestrol (DES), the value changed to 0.24 +/- 0.017. [131I]ITX at 6 h showed a tumor uptake value of 0.26 +/- 0.166; when rats were pretreated with DES, the value changed to 0.22 +/- 0.044. Priming tumor-bearing rats with estradiol, a tumor uptake value for [131I]ITX was increased to 0.48 +/- 0.107 at 6 h. In the [3H]estradiol receptor assay, tumors had a mean estrogen receptor density of 7.5 fmol/mg of protein. In gamma scintigraphic imaging studies with [131I]ITX, the rabbit uterus uptake can be blocked by pretreatment with DES. Both iodo-tamoxifen and tamoxifen reduced ER(+) breast tumor growth at the dose of 50 micrograms in tumor-bearing mice. The findings indicate that tamoxifen analogue uptake in tumors occurs via an ER-mediated process. Both analogues should have potential for diagnosing functioning ER(+) breast cancer.

Evidence for bimodal distribution of breast carcinoma ER and PgR values quantitated by enzyme immunoassay

Breast carcinoma oestrogen receptor (ER) and progesterone receptor (PgR) values obtained by radioligand binding assays have commonly been observed to have approximate log-normal distributions. We examined the distribution of log-transformed receptor values obtained by enzyme immunoassay for 5468 primary breast carcinomas in five Ontario laboratories. In each laboratory, it was found that the frequency histograms for the log transformed receptor values were not unimodal, and generally were suggestive of bimodality. This was not affected by stratification by age or inferred menopausal status (< or = 49, > or = 50 years), and could not be explained by kit characteristics. However, the low point in the distribution varied from 5 to 63 fmol/mg cytosol protein, depending on the receptor, patient age and laboratory. The tendency towards biomodality was more distinct for ER than for PgR. It remains to be determined whether the low points on the frequency histograms have clinical relevance for discriminating between hormone-sensitive and hormone-insensitive tumours.

Prognostic factors. Stage and receptor status in breast cancer

BACKGROUND

Anatomic and biologic indicators of prognosis provide the bases for management of patients with cancer of the breast. Combinations of these indicators are potentially more accurate than any alone. This review was undertaken to evaluate the prognostic relationship between stage and steroid hormone receptors.

METHODS

The literature was reviewed relative to the influences of tumor size, axillary metastases, and tumor estrogen receptors on the survival of patients with cancer of the breast.

RESULTS

Axillary node status is of primary importance as a predictor of recurrence and survival. Tumor size has only a secondary influence, but is prognostically useful in the absence of metastases. Estrogen and progesterone receptors provide prognostic information that is independent of axillary stage, but the influence is weak, often transient, and attributable at least partly to a close association with other biologic indicators of favorable prognosis.

CONCLUSIONS

Hormone receptors add to the prognostic information provided by anatomic stage, but the contribution is insufficient to support a decision for or against systemic adjuvant therapy.

Truncated forms of DNA-binding estrogen receptors in human breast cancer

The likelihood a breast cancer will respond to antiestrogen therapy depends on the tumor content of immunoreactive or ligand-binding estrogen receptor (ER). To investigate the failure of many ER-positive breast cancers to respond to antiestrogen therapy, we examined by gel-shift assay the ability of tumor ER to bind its cognate estrogen response element (ERE). Analysis of 38 primary breast cancers showed that some tumors containing abundant immunoreactive ER failed to demonstrate DNA binding ER. In many other ER-positive tumors, the fraction of DNA binding ER was low and consisted primarily of truncated receptor forms, which on Western analysis were revealed to be 50 kD homodimers and 67-50 kD ER heterodimers. The use of protease inhibitors during tumor extraction and the demonstration of nuclear-localizing ER and ERE-binding COUP (chicken ovalbumin upstream promoter) protein in these tumors indicated that the truncated forms of ER were likely present in vivo. The presence of intact DNA binding ER correlated with higher tumor content of immunoreactive sex steroid receptors (ER and/or PR), standard predictors of tumor responsiveness to antiestrogen, suggesting that loss or truncation of DNA binding ER may be an important prognostic parameter accounting for some forms of clinical resistance to antiestrogen therapy.

Medical management of early-stage breast cancer

With improved screening and education, a greater proportion of breast cancer is detected at an early stage. Although the prognosis for many of these patients is excellent following definitive local therapy alone, some subsets of node-negative patients have a 30% chance of eventually developing metastatic disease that will be incurable with current therapy. Thus, an increasing proportion of early-stage patients are being offered some form of adjuvant therapy, with the expectation of improved relapse-free survival, and possibly improved overall survival. Efforts have been made to base the selection of patients for adjuvant therapy on specific prognostic factors. Meanwhile, the scope and complexity of putative prognostic factors continues to widen, and now includes such items as the presence of occult microscopic metastases, DNA ploidy and proliferative fraction, cytogenetic abnormalities, oncogene expression, growth factor receptors, and expression of hormonally regulated proteins. In addition, there is now a considerable range of options with regard to the composition, dose intensity, and sequence of multimodality therapy. Data regarding the classification, significance, and interpretation of prognostic factors is reviewed together with the development, current status, and recommendations regarding adjuvant therapy for patients with early-stage breast cancer. For 1991, the National Cancer Institute (NCI) has estimated that 175,000 new cases of breast cancer will be diagnosed in American women. It is also estimated that 44,500 women will die of breast cancer. Unfortunately, the age-adjusted death rate from breast cancer has shown no overall change from 1930 through 1987. However, effective screening techniques continue to identify an increasing percentage of early-stage tumors, which should exceed 50% of all new tumors in 1991. Ultimately, our understanding of environmental and genetic risk factors may identify new ways to reduce the impact of this disease. In the interim, development and application of effective systemic adjuvant chemotherapy and hormonal therapy has become increasingly important. There is no question that a greater proportion of patients with less extensive disease are now being offered some form of adjuvant therapy. Meanwhile, selection of patients for adjuvant therapy, and choice among specific adjuvant regimens, has remained controversial. Analysis of multiple prognostic factors is performed not only in the context of cooperative investigational trials, but more often in the offices of individual physicians caring for individual patients. Tumor biopsies can now be routinely sent to specialized laboratories for performance of complex assays with potential prognostic information, although interpretation of these results with reference to a specific patient is often uncertain.(ABSTRACT TRUNCATED AT 400 WORDS)

Circumvention of doxorubicin resistance in multi-drug resistant human leukaemia and lung cancer cells by the pure antioestrogen ICI 164384

ICI 164384, a new steroidal antioestrogen, entirely devoid of oestrogenic activity, modulates doxorubicin resistance in vitro. At non-cytotoxic concentrations, ICI 164384 potentiated the cytotoxicity of doxorubicin in a dose-dependent manner in both the classical multi-drug resistant (MDR) human leukaemia cell lines CEM/VLB 100 and CEM/VLB 1000 and the human small cell lung cancer cell line H69 LX4. ICI 164384 had no effect on the two respective parental cell lines, CEM/CCRF and H69 P. None of these cell lines expressed the oestrogen receptor. In comparative studies at concentrations ranging from 1.25 to 10 mumols/l, ICI 164384 was significantly more effective (1.2-6-fold) than tamoxifen in reducing the IC50 of doxorubicin in the CEM/VLB 100 line. In resistant cells, ICI 164384 increased 3H-daunomycin accumulation in a dose-dependent manner and was significantly more effective than tamoxifen at concentrations ranging from 2.5 to 10 mumol/l. ICI 164384 reduced the efflux of daunomycin from resistant cells more effectively than tamoxifen. These studies suggest that ICI 164384 is an effective modulator of MDR.

Receptor-based assays

Receptor-based assays have benefitted from the newest advances in biotechnology and electronics in three main ways: genetically engineered cells expressing single receptor subtypes have been developed for many natural and synthetic ligands; assays have been designed which take advantage of a variety of signals triggered in cells by binding, or inhibition of binding, of ligands to surface-bound receptors; and radiolabelled ligand assays have been considerably improved and simplified by novel electronic devices.