Relationship between steroid receptors and response to endocrine therapy and cytotoxic chemotherapy in metastatic breast cancer

Progesterone receptor inhibits proliferation of human breast cancer cells via induction of MAPK phosphatase 1 (MKP-1/DUSP1)

The roles of progesterone (P(4)) and of progesterone receptor (PR) in development and pathogenesis of breast cancer remain unclear. In this study, we observed that treatment of T47D breast cancer cells with progestin antagonized effects of fetal bovine serum (FBS) to stimulate cell proliferation, whereas siRNA-mediated knockdown of endogenous PR abrogated progestin-mediated anti-proliferative effects. To begin to define mechanisms for the anti-proliferative action of P(4)/PR, we considered the role of MAPK phosphatase 1 (MKP-1/DUSP1), which catalyzes dephosphorylation and inactivation of MAPKs. Progestin treatment of T47D cells rapidly induced MKP-1 expression in a PR-dependent manner. Importantly, P(4) induction of MKP-1 was associated with reduced levels of phosphorylated ERK1/2, whereas siRNA knockdown of MKP-1 blocked progestin-mediated ERK1/2 dephosphorylation and repression of FBS-induced cell proliferation. The importance of PR in MKP-1 expression was supported by findings that MKP-1 and PR mRNA levels were significantly correlated in 30 human breast cancer cell lines. By contrast, no correlation was observed with the glucocorticoid receptor, a known regulator of MKP-1 in other cell types. ChIP and luciferase reporter assay findings suggest that PR acts in a ligand-dependent manner through binding to two progesterone response elements downstream of the MKP-1 transcription start site to up-regulate MKP-1 promoter activity. PR also interacts with two Sp1 sites just downstream of the transcription start site to increase MKP-1 expression. Collectively, these findings suggest that MKP-1 is a critical mediator of anti-proliferative and anti-inflammatory actions of PR in the breast.

The prognostic significance of single hormone receptor positive metastatic breast cancer: an analysis of three randomised phase III trials of aromatase inhibitors

We analysed the outcomes of women with metastatic breast cancer (MBC) from three randomised phase III trials of aromatase inhibitors according to oestrogen receptor (ER) and progesterone receptor (PgR) status. Both receptors were analysed in 1010 of the 1870 women (54%), including 31 that were ER-/PgR-, which were excluded. Of the remaining 979, 726 (74%) were ER+/PgR+ but 253 were single hormone receptor positive (213 ER+/PgR-, 40 ER-/PgR+). Although there were no differences in clinical benefit or time to progression, the median overall survival of women with ER+/PgR+ tumours was significantly longer than those with single HR positive tumours (800 versus 600 days, p=0.01). In women with ER+ tumours, the median overall survival of those with tumours that were also PgR+ was significantly longer than those that were PgR- (800 versus 625 days, p=0.02). The PgR status is an important prognostic factor for survival in MBC.

Adjuvant chemotherapy in oestrogen-receptor-poor breast cancer: patient-level meta-analysis of randomised trials

BACKGROUND

The long-term effects of adjuvant polychemotherapy regimens in oestrogen-receptor-poor (ER-poor) breast cancer, and the extent to which these effects are modified by age or tamoxifen use, can be assessed by an updated meta-analysis of individual patient data from randomised trials.

METHODS

Collaborative meta-analyses of individual patient data for about 6000 women with ER-poor breast cancer in 46 trials of polychemotherapy versus not (non-taxane-based polychemotherapy, typically about six cycles; trial start dates 1975-96, median 1984) and about 14 000 women with ER-poor breast cancer in 50 trials of tamoxifen versus not (some trials in the presence and some in the absence of polychemotherapy; trial start dates 1972-93, median 1982).

FINDINGS

In women with ER-poor breast cancer, polychemotherapy significantly reduced recurrence, breast cancer mortality, and death from any cause, in those younger than 50 years and those aged 50-69 years at entry into trials of polychemotherapy versus not. In those aged younger than 50 years (1907 women, 15% node-positive), the 10-year risks were: recurrence 33% versus 45% (ratio of 10-year risks 0.73, 2p<0.00001), breast cancer mortality 24% versus 32% (ratio 0.73, 2p=0.0002), and death from any cause 25% versus 33% (ratio 0.75, 2p=0.0003). In women aged 50-69 years (3965 women, 58% node-positive), the 10-year risks were: recurrence 42% versus 52% (ratio 0.82, 2p<0.00001), breast cancer mortality 36% versus 42% (ratio 0.86, 2p=0.0004), and death from any cause 39% versus 45% (ratio 0.87, 2p=0.0009). Few were aged 70 years or older. Tamoxifen had little effect on recurrence or death in women who were classified in these trials as having ER-poor disease, and did not significantly modify the effects of polychemotherapy.

INTERPRETATION

In women who had ER-poor breast cancer, and were either younger than 50 years or between 50 and 69 years, these older adjuvant polychemotherapy regimens were safe (ie, had little effect on mortality from causes other than breast cancer) and produced substantial and definite reductions in the 10-year risks of recurrence and death. Current and future chemotherapy regimens could well yield larger proportional reductions in breast cancer mortality.

Reduction of Human Metastatic Breast Cancer Cell Aggressiveness on Introduction of Either Form A or B of the Progesterone Receptor and Then Treatment with Progestins

The sex steroid hormone progesterone (Pg) is critically involved in the development of the mammary gland, and it also is thought to play a role in breast cancer progression. However, the effect of Pg on malignant phenotypes is not fully understood in breast cancer. We previously reported that in Pg receptor (PR)-positive T47D breast cancer cells, Pg was able to counterbalance the stimulatory effect of estrogen or serum on proliferation and on expression level of Id-1, which generally stimulates cell proliferation and inhibits differentiation. Conversely, metastatic MDA-MB231 breast cancer cells lack PR and express high levels of Id-1 constitutively, and Pg showed no effect on Id expression, proliferation, and invasion in these cells. However, after introducing PR (either PR-A or PR-B) into MDA-MB231 cells, Pg inhibited the expression of Id-1 mRNA drastically. PR-transfected MDA-MB231 cells exhibited less proliferative activity after Pg treatment than parental or control MDA-MB231 cells, an effect which correlated well with reduction of Id-1 mRNA. This inhibitory effect on proliferation was accompanied by p21 up-regulation and c-myc down-regulation. Moreover, Pg-treated PR transfectants showed significant morphologic change, appearing more flattened and spread out than control ethanol-treated cells. Boyden chamber invasion assay revealed that PR-transfected MDA-MB231 cells also lost most of their invasive properties after Pg treatment. Zymographic analysis revealed that Pg drastically inhibited matrix metalloproteinase-9 (MMP-9) activity in cells transfected with either PR-A or PR-B. To determine whether Id-1 could act as a key mediator of the effects of Pg, we prepared cells transfected with Id-1 and PR. The morphologic change and p21 up-regulation still were observed after Pg treatment. However, c-myc down-regulation was not observed; the proliferative and invasive activities were mostly recovered; and MMP-9 down-regulation could not be detected anymore. From these observations, we conclude that either form of the PR is sufficient to reduce the malignant phenotypes on treatment with Pg and that Id-1 plays an important role as a mediator of the effects of Pg on breast cancer cell proliferation and invasion.

Factors influencing the distribution of metastases and survival in metastatic breast carcinoma

A total of 370 patients with metastatic breast, carcinoma who had been followed at Hacettepe Oncology Department between 1980 and 1991 were retrospectively analyzed for the factors influencing the distribution of metastases and survival. Median age was 47 years. Radical or modified radical mastectomies were performed in 199 (53.8%). Infiltrative ductal carcinoma was the most common pathologic subtype (69.4%). In 191 patients who were evaluated for estrogen receptor (ER) status, 101 (52.9%) were positive and 90 (47.1%) were negative. The distribution of first metastases did not differ between the soft tissue, bone, and visceral sites. The second, third, and fourth metastases were more common in visceral sites (p < 0.05). ER and menopausal status did not affect distribution. Mortality rate was significantly lower in the group having the first metastasis to the bone (p < 0.05). Of interest, first metastases were predominantly found in visceral sites in patients having radical or modified radical mastectomies (p < 0.05). Response to therapy, presence of initial metastases, axillary status, and age were the important factors influencing the overall survival in univariate analysis, whereas response to therapy, ER status, age, and presence of initial metastases were the important factors according to the multivariate analysis.

Measurement of S-phase fraction and ploidy in sequential fine-needle aspirates from primary human breast tumours treated with tamoxifen

Sequential fine-needle aspirates (FNAs) for cytodiagnosis and flow cytometry were taken from 21 patients with primary breast carcinoma at intervals ranging from 1 to 3 months after the commencement of first-line tamoxifen therapy. Nine patients achieved a sustained complete or near complete response over a 3-9 month period. The tumour cells from seven out of nine of these patients were initially aneuploid, while the remaining two patients had diploid tumours. An analysis of sequential FNAs showed that, in three out of the seven aneuploid tumours, only benign epithelial cells could be detected by cytology in the post-tamoxifen sample. In the remaining six cases, including the two diploid tumours, there was no change in ploidy but a reduction in S-phase fraction (SPF) to approximately 50% of the pretreatment level. In all cases, these changes in ploidy or SPF were seen with a mean lead time of 4 months before the tumour had reached clinical complete remission. None of these patients have relapsed after a mean follow-up period of 18 months. The tumours of 12 patients achieved no more than a temporary partial response to primary tamoxifen therapy. In seven out of eight of these cases, which were all initially aneuploid, sequential FNAs during tamoxifen therapy revealed either an increase or no change in the SPF with the tumour remaining aneuploid. In the remaining four cases the tumours were all recorded as being diploid in the pretreatment sample. However, although three of these cases had a temporary partial response to tamoxifen, an aneuploid component was picked up in repeat sequential FNAs with a mean lead time of 5 months before clinical confirmation of eventual disease progression. We conclude that changes in ploidy and SPF detected by flow cytometry may predict initial response and the likelihood of relapse of breast tumours to tamoxifen before clinical changes become evident. These data justify a larger study.

Steroid receptor enhancement by natural interferon-beta in advanced breast cancer

In the current study we investigated the effect of two different doses of natural interferon-beta (IFN-beta) on steroid hormone receptors in 45 patients with advanced breast cancer. IFN-beta seems to regulate the receptor mechanisms, inducing in cutaneous metastases an increase of oestrogen and progesterone receptors. Moreover, using IFN-beta and tamoxifen as a combined therapy in 23 receptor-positive patients, no negative interference of the two drugs was observed and no relevant side-effects due to the treatment were noticed. The modulation of steroid receptor content by IFN-beta in advanced breast cancer might represent an interesting way to ameliorate the clinical responsiveness to anti-oestrogens.

Differential response to chemotherapy in metastatic breast cancer in relation to estrogen receptor level. Results of a prospective randomized study

The predictive value of estrogen receptor (ER) level for response to chemotherapy was studied in 182 patients with metastatic breast cancer in a prospective study. Patients were stratified according to ER status and dominant site of disease and randomized to one of three regimens: cyclophosphamide, 5-Fluorouracil, and prednisone (CFP) versus CFP, methotrexate, and vincristine (CFPMV) versus doxorubicin and cyclophosphamide (AC). There was no significant differences in all response categories (P = 0.21), was taken as a predictor for response to chemotherapy, there was no significant difference in overall response (P = 0.61) between ER+ (62/108, 57%) and ER- patients (31/49, 63%). However, there was a significant trend toward a higher degree of response in ER- patients (more complete response [CR] nine of 49, 18%, and fewer failures six of 49, 12%) than in ER+ (less CR seven of 108, 7%, and more failures 37/108, 34%) (P = 0.006). Patients with higher measured levels of ER showed worse response (Kendall's tau C, P = 0.026). This trend for ER- patients to have better response than ER+ patients was generally consistent, regardless of the predominant site of metastases or chemotherapy regimen (P = 0.04 for CFP; P = 0.08 for CFPMV; and P = 0.20 for AC). The advantage of a better response for ER- patients was nullified by an earlier relapse which was reflected in longer duration of remission, time to treatment failure, and survival in favor of ER+ patients (12.3 months versus 7.3 months remission duration, 18.7 months versus 13.6 months survival in partial responders). These data suggest that ER- patients respond to a higher extent to chemotherapy but relapse sooner than ER+ patients, suggesting a more rapid growth for ER- tumors. In patients with ER- tumors and poorer prognosis on conventional chemotherapy, new trials of intensive consolidation after response should be considered.

Steroid receptors, cellular kinetics, and lymph node status as prognostic factors in breast cancer

Steroid receptor status, cellular kinetics, abnormal proto-oncogene presence, and lymph node metastases all have been shown to provide prognostic information in breast cancer. The factors guide the choice of therapy and predict the course of the disease. Both disease-free survival and overall survival are predicted by these variables. Steroid receptors are the most reliable predictor of hormonal responsiveness. Lymph node involvement is crucial in determining the extent of the disease and the need for adjuvant therapy. Cellular kinetics and abnormal proto-oncogene presence predict tumor aggressiveness. Together these prognostic factors provide considerable information to the clinician.

Hormone receptor assays: clinical usefulness in the management of carcinoma of the breast

The revision of the subcellular model of hormone action is described, with an incorporation of potential autocrine mechanisms. A general overview of available assay methodologies considers the major disadvantages of earlier methods and describes in detail the current methodologies (sucrose gradient analysis, dextran-coated charcoal assays, ER-EIA, ERICA). A major concern with clinical correlations of response to hormone receptor levels is the quality assurance of the multicentric programs. Results from national and international programs are considered. The clinical correlations are divided into four major categories: (1) the response to hormone deprivation (oophorectomy or adrenalectomy), (2) the development of specific agents which exploit receptor mechanisms (antiestrogens) or inhibit steroid biosynthesis (aminoglutehimide), (3) the rates of recurrence of tumors following mastectomy, and (4) the correlation of hormone receptors with current adjuvant therapies.

Pathologic findings from the national surgical adjuvant breast project. Correlations with concordant and discordant estrogen and progesterone receptors

Pathologic materials were available for review from 1597 women with Stage II (positive regional node metastases) invasive breast cancer in whom estrogen receptor (ER) and progesterone receptor (PR) assays of the primary tumor were performed. These women were enrolled in a clinical trial comparing the effect of postmastectomy adjuvant L-phenylalanine mustard (L-PAM) and 5-fluorouracil (5-FU) with and without tamoxifen (NSABP Protocol No. 9). Significant pathologic and clinical associations with receptor status were similar for both ER and PR except that the latter, unlike ER, was not related to patient age. Regression analyses revealed that the most significant pathologic features related to a concordant positive ERPR receptor status was low (well differentiated) nuclear and histologic grades, slight or absent tumor lymphoid infiltrate, slight or absent necrosis and moderate or marked elastica in decreasing order of importance. All of the factors enumerated are directly or indirectly related to tumor differentiation. Recognition of four or five conforming pathologic features allows for the prediction of either ER or PR status in 70% to 80% of instances respectively, and the presence of three features in 69%. This latter figure is similar to that of estimation of nuclear grade alone. Thirty percent of ERPR estimates were discordant i.e., either ER-PR+ or ER+PR-. Pathologic features associated with discordant assays were not similar to those found when the ERPR estimates were concordant. Life table analyses revealed patients with discordant receptors to exhibit disease-free survival intermediate to that of those with ER+PR+ and ER-PR- values. This information suggests that a discordant receptor status is more reflective of an aberration of ER metabolism than a methodologic error. Histograms correlating frequency of nuclear grades with levels of ER and PR were comparable and revealed patterns indicating the propriety of relating values less than 10 fm/mg as being receptor negative. The frequency of well-differentiated nuclei increased with ascending levels of ER and PR.

The structure and function of progesterone receptors in breast cancer

This paper is a review of the clinical role of progesterone receptors (PR) in the management of breast cancer, and the use of synthetic progestins in treatment of the metastatic disease. Also reviewed are our basic molecular studies dealing with the structure of human breast cancer PR, focusing on the two hormone binding proteins (the A- and B-receptors) and the role of phosphorylation. A model for the structure of PR and their subcellular compartmentalization following hormone treatment is presented.

Correlation of steroid receptors with histologic differentiation in mammary carcinoma. A Singapore experience

Cancer of the breast is the most common tumor in females in Singapore, with the rate of 20.7 per 100,000 per year (1977 estimate), which is predicted to increase to 29.8 per 100,000 women per year by 1995. A detailed histopathologic review of 50 primary breast cancer tumors analyzed for estrogen receptor (ER) level was carried out and a variety of morphologic features correlated with ER results to identify any factors that will improve the management and prognosis for breast cancer. Cytosol was incubated with 3H-estradiol in the presence and absence of cold diethylstilbestrol, and bound and free hormone were separated by Dextran-coated charcoal method. Tumors binding more than 5 fmol/mg cytosol protein were classified as ER-positive. Progesterone receptor (PR) level was analyzed in some specimens with the use of a similar method. Most of the patients were Chinese (90%). Three patients were Malays, one was Indian, and one was European in this series. Results indicated that there was strong correlation between ER level, age, and histologic grade of the tumors. No correlation existed between absence or presence of lymph node metastases and ER. Although there was a trend for ER-positive tumors to have a low-grade lymphocytic infiltration, the difference was not statistically significant.

Prognostic value of estrogen receptors determined by radiochemical vs. histochemical methods in breast cancer

Estrogen receptors (ER) were evaluated in 634 breast cancer patients by the dextran-coated charcoal method (DCC). In 206, ER and progesterone receptors (PR) were also tested by cytochemistry (Lee method), and in 124 ER were tested by immunofluorescence (Pertschuk method). The median follow-up is 3.7 years. Comparisons have been made between receptor content and: anatomical and clinical features, disease-free survival (DFS), and survival. The following conclusions can be drawn: there is no correlation between ER determinations by DCC and by immunofluorescence or cytochemical methods; there is no evidence of association between ER and PR determined by Lee's method and anatomical and clinical features; a highly significant positive association was found between ER rich specimens and age, post-menopausal status, lobular and tubular histologic types; there is no association between ER values and TNM stage, WHO grading, pathologic prognostic factors of primary tumor and of lymph nodes; and the DFS was not affected by ER status, except for tumors with more than 50 fmol/mg protein.

Chemotherapy of breast cancer

Carcinoma of the breast will prove fatal to over 37,000 women in the United States in 1983, despite attempts at early diagnosis. Hormonal manipulation, known to provide effective palliation for many years, can now be effectively aimed at receptor positive women who have a 50-70% chance of responding. Newer agents, such as tamoxifen and aminoglutethimide offer the benefits of older treatments with less morbidity. Investigations of drugs acting at the level of the central nervous system are ongoing. Single agent chemotherapy is clearly effective in causing tumor regression, but effective combination chemotherapy provides more responses and a longer duration of response. The most effective combination regimens at present contain doxorubicin. Pharmacologic studies at the cellular level can be expected to provide more effective combinations. The most effective way to combine hormonal and chemotherapeutic treatments is not known. In receptor positive women without life-threatening disease, beginning with hormonal treatment may be effective in providing palliation at low toxic cost without jeopardizing overall survival. New efforts to cure clinically manifest metastatic breast cancer may eschew palliation as a prime goal. Techniques of synchronizing and of stimulating breast cancer to increase its susceptibility to cytotoxic drugs are under investigation. Immunotherapy is not established as a beneficial modality in the treatment of breast cancer, although levamisole has led to suggestive benefit in small controlled trials. The use of chemotherapy, and possibly of some hormonal treatments in appropriate patients, as an adjuvant to surgery prolongs disease-free survival. This approach, using established chemotherapeutic and hormonal agents when the metastatic disease is subclinical, is consonant with abundant evidence from experimental systems and other human cancers that are curable. Expectation of curing human breast cancer will likely require aggressive action at the time when the total body tumor burden is at a minimum.

Relation of estrogen and/or progesterone receptor content of breast cancer to patient outcome following adjuvant chemotherapy

In 1977 the National Surgical Adjuvant Breast and Bowel Project (NSABP) initiated a prospectively randomized clinical trial to evaluate the relative merits of 1-phenylalanine mustard and 5-fluorouracil (PF) with and without tamoxifen (T) as adjuvant therapy for patients with primary breast cancer and positive axillary nodes. A previous presentation of findings noted that there was a strong relationship between the outcome of those receiving PFT and the estrogen receptor (ER) and progesterone receptor (PR) content of their tumors. This report relates the outcome of the PF-treated patients in that trial with these tumor receptors. It indicates that the results observed following nonhormonal therapy (PF) are also related to tumor receptors. Both the disease-free survival (DFS) and survival (S) of women following PF therapy were influenced by the ER and PR content of their tumors. Subsequent to adjustment for other prognostic variables, the predictive influence of tumor ER persisted. Both the DFS (p = 0.0003) and the S (p = 0.00003) were significantly higher in those with greater than or equal to 10 fmol tumor ER than in those with less than 10 fmol ER. The PR significantly added to the predictive value of ER. Thus, this analysis is the first to demonstrate that having information on both ER and PR is important for predicting outcome of patients receiving adjuvant chemotherapy. The study does not provide information which correlates receptor status with the response of patients to adjuvant chemotherapy since there is no similar nonchemotherapy-treated group of patients in the trial. The findings continue to emphasize that there is a heterogeneity in outcome of breast cancer patients to adjuvant chemotherapy which is related to an increasing number of host and tumor variables. For proper assessment of overall results, it is essential that analyses employ tests for interaction to indicate homogeneity or heterogeneity of patient subsets and that adjustments be made for imbalances in tumor ER and PR as well as in other prognostic factors.

Progesterone receptors and human breast cancer

Estrogen receptor protein is known to be an important prognostic factor for patients with breast cancer. The presence of estrogen receptor correlates with response to endocrine therapy in patients with metastatic disease and is associated with prolonged disease-free and overall survival in patients with primary disease. But the correlation between estrogen receptor positivity and endocrine dependence is not perfect. Approximately 40% of estrogen receptor positive tumors fail to regress with endocrine therapy. It has been hypothesized that another protein, progesterone receptor, may be a more effective marker of endocrine responsiveness since progesterone receptor is the end product of estrogen action. We have examined the relationship between progesterone receptor and response of advanced breast cancer tumors to hormonal manipulations. Promising retrospective results indicate the need for new, prospective clinical trials to further define the prognostic value of progesterone receptor for these tumors. We have also analyzed the disease-free intervals of patients with primary disease and found that progesterone receptor was more important than estrogen receptor for predicting time to recurrence. We suggest that both estrogen receptor and progesterone receptor be routinely measured in all breast cancer tumors, and that the results of these assays will help the physician individualize therapy for breast cancer patients.

Estrogen and progesterone receptors: correlation of response rates, site and timing of receptor analysis

156 patients with advanced breast cancer of known estrogen receptor (ER) and progesterone receptor (PgR) status treated by endocrine therapy were studied. Regarding values for ER and PgR greater than or equal to 5 fmole/mg cytosol protein as positive, patients were divided into 4 phenotypic subgroups: ER+PgR+ (43%), ER+PgR- (26%), ER-PgR+ (8%), and ER-PgR- (23%). In patients with tumor phenotype ER+PgR+, responses were seen in 20/30 (67%) assessable initial treatments when receptor assays were performed on tumor recurrence or on primary tumor immediately before endocrine therapy, and in only 11/32 (34%) assessable initial treatments when receptor analysis was performed on primary tumor and there was intervening local therapy before endocrine therapy was started for tumor recurrence (P less than 0.05). Responses to first endocrine therapy for each tumor phenotype were ER+PgR+ 50%, ER+PgR- 27%, ER-PgR+ 27%, and ER-PgR- 6%. Four of 16 (25%) patients with ER+PgR+ tumors responded to subsequent secondary endocrine therapy, but such responses were not observed in 20 patients with other tumor phenotypes. Duration of response was similar for each phenotype, but patients with ER-PgR- tumors had a significantly shorter survival from time of initial endocrine treatment than patients of any other phenotype. These results suggest that repeat steroid receptor assays on accessible tumor immediately before endocrine therapy may result in improved predictability.