Is the negative prognostic value of high oestrogen receptor (ER) levels in postmenopausal breast cancer patients due to a modified ER gene product?

Relationship between Steroid Receptors (As Continuous Variables) and Response to Adjuvant Treatments in Postmenopausal Women with Node-Positive Breast Cancer

In current clinical practice for breast cancer patients, estrogen (ER) and progesterone receptor (PgR) concentrations, quantified by the dextran-coated charcoal assay, are categorized by an arbitrary cutoff into a negative or positive status. However, although the results obtained with this approach are easy to interpret, such a representation could oversimplify the relationship between ER and PgR content and patient outcome and imply an assumption of monotonicity, which is generally expected but rarely proven. We evaluated the relationship between ER and PgR content (considered on a continuous scale) and clinical outcome, using a flexible statistical model, in a group of postmenopausal patients with N-positive operable tumors who were submitted to surgery and different adjuvant treatments (tamoxifen or CMF). Univariate analysis indicated that in the tamoxifen-treated group, ER level, number of metastatic nodes (pN) and age, but not PgR, were significant indicators of clinical outcome (p=0.032, p=0.021 and p=0.029, respectively). Multivariate analysis indicated that in this group of patients there was no interaction between variables, and in the final model for disease-free survival (DFS) only ER and pN were retained with an overall predictive ability of the regression model of 0.723, as evaluated by Harrell's c. However, pN markedly contributed to the predictive ability of the model with respect to ER, since a marked decrease in Harrell's c statistic (c=0.582) was observed when pN was removed from the model. In the CMF-treated group, only pN affected clinical outcome. When the estimated DFS curves obtained from the final Cox regression models were plotted according to four values of ER (in the tamoxifen-treated group) or three values of pN (in the CMF-treated group) we observed that in the tamoxifen-treated group patients with an ER concentration equal to 0 fmol/mg cytosol protein had the worst prognosis, whereas a marked improvement of the expected DFS was observed for patients with a low but detectable ER level (generally classified as ER-negative because falling below the conventional cutoff value of 10 fmol/mg cytosol protein). Our results seem to suggest that the use of steroid receptor concentrations on a continuous scale, instead of dichotomous “status”, is to be preferred in the choice of adequate therapeutic strategies.

Is Adjuvant Tamoxifen Recommended in Post-Menopausal Node-Negative Breast Cancer Patients with High Estrogen Receptor Values?

The impact of ER levels on the response to tamoxifen was evaluated in 1,623 postmenopausal primary breast cancer patients treated at our center (median follow-up 8.2 years). In patients receiving adjuvant tamoxifen a significantly longer disease-free survival (DFS) was observed when ER levels were elevated (p<0.00001). Very high ER (>424 fmol/mg protein) appeared to be detrimental in node-negative patients not treated with tamoxifen.

Estrogen receptor quantitative measures and breast cancer survival

PURPOSE

While the estrogen receptor (ER) is the single most widely used biomarker to evaluate breast cancer outcomes, aspects of ER marker biology remain poorly understood. We sought to determine whether quantitative measures of ER, such as protein expression and intensity, were associated with survival, or with survival disparities experienced by Hispanic women.

METHODS

A case-cohort study included a 15% random sample of invasive breast cancer cases diagnosed from 1997 to 2009 in six New Mexico counties and all deaths due to breast cancer-related causes. Pathology reports and tissue microarrays served as sources of ER information. Analyses were restricted to women with ≥1% ER immunohistochemical staining. Hazard ratios (HR) and 95% confidence intervals (CI) for breast cancer death were estimated using Cox proportional hazards models.

RESULTS

Included women represented 4336 ER+ breast cancer cases and 448 deaths. Median follow-up was 93 months. ER percent expression was not associated with breast cancer survival after adjustment for standard prognostic factors (p trend = 0.76). ER intensity remained a strong and independent risk factor for breast cancer survival in multivariate analyses: Women whose tumors expressed ER at intensity = 2 (HR 0.6; 95% CI 0.4-1.0) or 3 (HR 0.5; 95% CI 0.2-0.9) had a reduced risk of breast cancer mortality, compared to ER intensity = 1 (p trend = 0.02). Neither ER protein expression nor intensity influenced Hispanic survival disparities.

CONCLUSIONS

Estrogen receptor percent positive staining is not independently related to breast cancer survival after adjustment for other survival-related factors. ER intensity, in contrast, demonstrates promise for prognostic utility.

The immune system and inflammation in breast cancer

During different stages of tumor development the immune system can either identify and destroy tumors, or promote their growth. Therapies targeting the immune system have emerged as a promising treatment modality for breast cancer, and immunotherapeutic strategies are being examined in preclinical and clinical models. However, our understanding of the complex interplay between cells of the immune system and breast cancer cells is incomplete. In this article, we review recent findings showing how the immune system plays dual host-protective and tumor-promoting roles in breast cancer initiation and progression. We then discuss estrogen receptor α (ERα)-dependent and ERα-independent mechanisms that shield breast cancers from immunosurveillance and enable breast cancer cells to evade immune cell induced apoptosis and produce an immunosuppressive tumor microenvironment. Finally, we discuss protumorigenic inflammation that is induced during tumor progression and therapy, and how inflammation promotes more aggressive phenotypes in ERα positive breast cancers.

A multidisciplinary approach to the management of breast cancer, part 1: prevention and diagnosis

Breast cancer is the most common cancer among women in the United States, with an estimated 200,000 new cases diagnosed annually. A multidisciplinary focus that entails prevention, diagnosis, and treatment has led to significant strides in the reduction of breast cancer incidence and mortality. Additionally, breast cancer management has become increasingly complex, requiring comprehensive assessment and review of multiple issues that include the role of genetic testing, imaging and breast magnetic resonance imaging, surgical and reconstructive options, and a variety of new adjuvant therapies. It has become more evident that a multidisciplinary team approach that involves a spectrum of breast experts is necessary to provide optimal care to patients. This team includes medical oncologists, breast radiologists, breast pathologists, surgical breast specialists, radiation oncologists, geneticists, and primary care physicians. Furthermore, patient knowledge has increased use of the Internet, and more patients are seeking a multidisciplinary approach to treatment. This review considers information for health care professionals who will facilitate optimal patient care for women at increased risk for or presenting with a new diagnosis of breast cancer. The multidisciplinary team of authors, representing the different disciplines, has selected important state-of-the-art issues that arise in their daily practices for consideration, rather than summarizing what is already available in textbooks.

Interplay between the levels of estrogen and estrogen receptor controls the level of the granzyme inhibitor, proteinase inhibitor 9 and susceptibility to immune surveillance by natural killer cells

Estrogens promote cell proliferation and metastases in several human cancers. Here, we describe a different action of estrogens likely to contribute to tumor development-blocking immunosurveillance. In breast cancer cells, increasing concentrations of estrogen induce increasing levels of the granzyme B inhibitor, SerpinB9/proteinase inhibitor 9 (PI-9) and progressively block cell death induced by NK92 natural killer (NK) cells, but do not block killing by a second NK cell line, NKL cells. RNA interference knockdown of PI-9 abolishes estrogen's ability to block NK92 cell-induced cytotoxicity. Expressing elevated levels of estrogen receptor alpha (ERalpha) increases the induced level of PI-9, and makes tamoxifen (TAM), but not raloxifene or ICI 182,780, a potent inducer of PI-9. At elevated levels of ERalpha, induction of PI-9 by estradiol or TAM blocks killing by both NK92 and NKL cells. When the Erk pathway is activated with epidermal growth factor, the concentration of estrogen required to induce a protective level of PI-9 is reduced to 10 pM. Elevated concentrations of estrogen and ER may provide a dual selective advantage to breast cancer cells by controlling PI-9 levels and thereby blocking immunosurveillance. Expressing elevated levels of ERalpha reveals a potentially important difference in the effects of TAM, raloxifene and ICI 182,780 on immunosurveillance in breast cancer.

Altered target gene regulation controlled by estrogen receptor-alpha concentration

Estrogen receptor-alpha (ERalpha) is a transcriptional activator whose concentration is tightly regulated by the cellular environment. In breast tumors of postmenopausal women, elevated receptor concentrations can be associated with negative clinical outcomes, yet it remains poorly understood how such high levels impact ERalpha function. We previously demonstrated that high nuclear concentrations of ERalpha in breast cancer cells bypass the requirement for ligand and are sufficient to activate transcription and accelerate proliferation. Here, we extended those studies and asked whether the transcriptional targets and activation mechanism are similar or different from that of estrogen-stimulated ERalpha. We found that at elevated levels, ERalpha activated, but could not repress, known estrogen-responsive genes. Moreover, the set of activated genes was expanded to include the uterine-restricted target gene, complement component 3. The activation mechanism of ERalpha under these conditions depends both on activation function-1 and residues in the proximal region of the ligand-binding domain. Mutations of aspartate 351 and leucine 372 can inhibit ERalpha transcriptional activity gained at high concentrations and discriminate concentration-inducible ERalpha function from that induced by estrogen. Moreover, we demonstrate that at high levels, ERalpha stimulates transcription without recruiting steroid receptor coactivator-3 and without interference by a Gal4-receptor interaction domain box fusion protein containing LxxLL motifs, further distinguishing this mode of regulation from known activation mechanisms. Together these results demonstrate that the concentration of receptor in breast cancer cells can influence the pattern of target gene expression through a noncanonical activation mechanism.

Increases in estrogen receptor-alpha concentration in breast cancer cells promote serine 118/104/106-independent AF-1 transactivation and growth in the absence of estrogen

A common phenotype in breast cancer is the expansion of the estrogen receptor-alpha (ER+) cell population and an inappropriate elevation of ERalpha protein, the latter predisposing patients for a poorer prognosis than those with lower levels of the receptor. A tetracycline-inducible ERalpha overexpression model was developed in the MCF-7 cell line to assess induction of endogenous gene activation and growth in response to elevations in ERalpha protein. Heightened levels of ERalpha resulted in aberrant promoter occupancy and gene activation in the absence of hormone, which was independent of ligand and AF-2 function. This increased receptor activity required the amino-terminal A/B domain and was not inhibited by tamoxifen, which supports an enhancement of AF-1 function, yet was independent of serine-104, 106, and 118 phosphorylation. Ligand-independent transcription was accompanied by an increase in growth in the absence of hormonal stimulation. The results suggest that elevated levels of ERalpha in breast cancer cells can result in activation of receptor transcriptional function in a manner distinct from classical mechanisms that involve ligand binding or growth factor-induced phosphorylation. Further, they describe a potential mechanism whereby increases in ERalpha concentration may provide a proliferative advantage by augmenting ERalpha function regardless of ligand status.

Progesterone receptor quantification as a strong prognostic determinant in postmenopausal breast cancer women under tamoxifen therapy

There is now an emerging body of evidence that shows there is a relationship between the survival of breast cancer patients and the expression level of steroid receptors. The aim of this study was to determine the relationship existing between estrogen receptors (ER) and progesterone receptors (PR) cytosolic content and the prognosis of postmenopausal breast cancer women under tamoxifen therapy. Two hundred and nineteen postmenopausal patients, without neoadjuvant chemotherapy and treated postoperatively with tamoxifen for at least 2 years, were followed up in our Cancer Center. We used flexible regression modeling and log likelihood methods for determining optimum cut-off values for steroid receptors, which allows the separation of patients into significantly different categories in term of survival. For PR, 3 categories were defined (category 1: PR < 10, category 2: 10 < or = PR < 60 and category 3: PR > or = 60 fmol/mg P). Univariate analysis at 8 years indicated that significant differences in event-free survival (EFS) were found for tumor size (T) (p = 0.005), lymph node status (N) (p = 0.003), histological Scarff, Bloom and Richardson grade (p = 0.003), ER values divided into 5 categories (p = 0.02) and PR values divided into 3 categories (p = 1 x 10(-5)). Eight-year EFS rate for the 3 PR categories, adjusted for N, were 39, 66 and 81%, respectively. Multivariate Cox analysis indicated that only T, N and PR values were significant variables for EFS. Patients with PR values > or = 60 present significantly greater EFS rates than patients with PR < 60 (p < 0.001). Our results show that the PR level in ER positive postmenopausal women is a strong prognostic marker in postmenopausal breast cancer women under tamoxifen therapy.

Hormone receptors and proliferation in breast carcinomas of equivalent histologic grades in pre- and postmenopausal women

Breast cancers in younger, premenopausal women are more likely to exhibit an adverse prognostic profile (including negative steroid hormone receptors and a high rate of cellular proliferation) and poor outcome than breast cancers in postmenopausal women. It has been hypothesized that this adverse prognostic profile is a result of the higher histologic grade of breast cancers in pre- compared with post-menopausal women. To assess the association of expression of steroid hormone receptors and indicators of proliferation while controlling for histologic grade, we identified 100 infiltrating ductal carcinomas from premenopausal women 45 years of age or younger and 100 from postmenopausal women 65 years of age or older. The carcinomas were selected so that the histologic grades (low versus high) were distributed equally between the 2 groups. Estrogen receptors (ER), progesterone receptors (PR), p27(Kip1) and Ki-67 (to measure rate of proliferation) were assessed by immunohistochemistry and compared between groups. Clinical information and survival data were also analyzed. ER content was lower and proliferation was higher in carcinomas in premenopausal women (p = 0.048 and p = 0.005, respectively). By univariate analysis, p27(Kip1) and PR were not different between the groups; however, in multivariate analysis, p27(Kip1) was higher in postmenopausal women, but only in a subgroup with highly proliferative carcinomas. Overall survival was similar in the pre- and postmenopausal women. Furthermore, low p27(Kip1) and African-American ethnicity predicted a poorer overall survival in the premenopausal, but not in the postmenopausal, women in our study. After controlling for histologic grade, a lower expression of ER and a higher proliferative index were detected in breast carcinomas in premenopausal women. Therefore, some prognostic indicators, such as ER and proliferative rate, may be more closely associated with menopausal status than histologic grade. Our data also suggest that some prognostic factors are not equally effective as predictors of survival in pre- and postmenopausal women.

Oestrogen/insulin-like growth factor-I receptor interaction in early breast cancer: clinical implications

The expression of oestrogen receptor (ER) and that of the insulin-like growth factor-I receptor (IGF-IR) are positively correlated in breast cancer specimens. Their function is strongly linked in enhancing proliferative activity in normal and malignant human mammary epithelial cells in culture. This review examines the likely role of such a mechanism in the increased breast cancer risk reported in postmenopausal women with abdominal obesity. Precancerous breast lesions show an increased proportion of ER-positive cells with high proliferative activity, and recent studies suggest that genetic mutations or epigenetic variants in the ER alpha gene may increase the ER's sensitivity to oestrogen stimulation. Abdominal obesity in women is associated with higher concentrations both of free oestradiol and free IGF-I. Activation of their respective receptors may induce synergistic stimulation of mammary carcinogenesis. However, there is clinical evidence that progression in precancerous breast lesions may be delayed or reversed. Involution occurs spontaneously in a proportion of duct carcinoma in situ (DCIS) (intraductal) lesions as women approach the menopause, and antioestrogen therapy has been shown to reduce recurrence and progression of DCIS lesions.

CONCLUSIONS

Intervention trials in breast cancer prevention would greatly benefit from surrogate response markers which could predict long-term benefit. Changes in ER and IGF-IR expression apart from those in standardised cytomorphological criteria, might predict the likelihood of DCIS involution in cancer prevention trials. Future studies could involve examination of serial core biopsies from normal breast tissue during trials of antioestrogens, retinoids or weight-reduction interventions. Correlation of changes in these markers with changes in circulating IGF-I and oestradiol concentrations may help to clarify the roles of the markers.

Biomarker prediction of clinical outcome in operable breast cancer patients treated with tamoxifen

The predictivity of tumour size, oestrogen (ER) and progesterone (PgR) receptors, 3H-thymidine labelling index (TLI), c-erbB-2 and p27kip1 expression on clinical outcome was analysed on a consecutive series of 118 postmenopausal patients with ER-positive, node-positive tumours. All patients were treated with surgery +/- radiotherapy and adjuvant tamoxifen (30 mg/day) for at least 2 years. TLI, ER, c-erbB-2 and p27kip1 were generally unrelated to each other. PgR was directly related to ER and inversely to c-erbB-2. Tumour size was inversely related to both c-erbB-2 and p27kip1 expression. At a median follow-up of 75 months, 5-year relapse-free survival was significantly lower for patients with very rapidly proliferating (HR = 2.61, 95% CI = 1.34-5.08), PgR negative (HR = 2.76, 95% CI = 1.43-5.33) or relatively low ER content (HR = 2.20, 95% CI = 1.14-4.25) tumours than for patients with tumours expressing the opposite biological profiles. Overall survival was also significantly different as a function of TLI (HR = 3.47, 95% CI = 1.52-7.93) and PgR (HR = 2.27, 95% CI = 1.00-5.15). TLI and PgR maintained an independent relevance in multivariate analysis and together were capable of identifying subgroups of patients at significantly different risk of relapse and death.

Is chemotherapy alone adequate for young women with oestrogen-receptor-positive breast cancer?

BACKGROUND

The prognosis of breast cancer in very young women is generally considered to be unfavourable. Therefore, the outcome of adjuvant therapy was analysed in a population of young (<35 years) premenopausal patients treated in four randomised controlled trials.

METHODS

Between 1978 and 1993 the International Breast Cancer Study Group (IBCSG) treated 3700 premenopausal and perimenopausal patients with various timing and duration of adjuvant cyclophosphamide, methotrexate, and fluorouracil (CMF with or without low-dose prednisone and oophorectomy). 314 of these women were less than 35 years old at randomisation.

FINDINGS

Relapse and death occurred earlier and more often in younger (<35 years) than in older (> or = 35) patients with a 10 year disease-free survival of 35% (SE 3) versus 47% (1) (hazard ratio 1.41 [95% CI 1.22-1.62], p<0.001) and overall survival of 49% (3) versus 62% (1) (1.50 [1.28-1.77], p<0.001). Younger patients with oestrogen-receptor positive tumours had a significantly worse disease-free survival than younger patients with oestrogen-receptor negative tumours. By contrast, among older patients the disease-free survival was similar irrespective of oestrogen-receptor status.

INTERPRETATION

Young premenopausal breast cancer patients treated with adjuvant CMF chemotherapy had higher risk of relapse and death than older premenopausal patients, especially if their tumours expressed oestrogen receptors. The endocrine effects of chemotherapy alone are insufficient for the younger age group and these patients should strongly consider additional endocrine therapies (tamoxifen or ovarian ablation) if their tumours express oestrogen receptors.

The Estrogen Receptor Paradox in Breast Cancer: Association of High Receptor Concentrations with Reduced Overall Survival

Occasional reports have suggested an unfavorable effect of high estrogen receptor (ER) concentrations in primary breast cancer. In a population-based study we identified a subgroup explicitly exhibiting this seemingly paradoxical effect. ER concentrations were prospectively measured in a single laboratory by multipoint DCC assay. The relative risk of death in relation to the concentration of the interval-scaled variables ER and PgR was continually estimated by serial Cox regression analyses. Thus we circumvented loss of information due to primary categorization and avoided assumptions about relations between factor and risk. Based on 2,735 consecutively accrued primary breast cancer cases (median follow-up 56 months) we identified node-negative patients up to 60 years of age as the relevant subpopulation. High (>/=300 fmol/mg protein) ER concentrations exhibited an even more unfavorable impact (p < 0.03) on overall survival than ER concentrations of less than 10 fmol/mg protein. The well-known association of age and ER concentration was definitely excluded as an underlying biological cause for the increased risk. Differences in the distribution of other prognostic factors (HER-2/neu, Ki-67, DNA ploidy) were also excluded. As we observed a preponderance of pT2 tumors in the high ER group, we repeated the analysis, selectively focusing on pT2 tumors in the relevant subgroup, but the effect remained unchanged. In contrast, node-positive patients adjusted for age significantly (p = 0.02) profited from high ER concentrations as compared to the ER-negative group. As the phenomenon did not occur in node-positive patients, receptor defects in the high-ER group seem unlikely. To the contrary, we suspect that ER overexpressing cells are hypersensitive even to low levels of estrogens. Once they have sneaked past local barriers prior to primary surgery, they may cause early death in the absence of appropriate adjuvant endocrine therapy.

Quantitative determination of c-erbB-2 in human breast tumours: potential prognostic significance of low values

The purpose of this prospective multicentric study was to quantify the c-erbB-2 protein and investigate its relationship with DNA amplification and with various prognostic parameters of breast cancer. A total of 1062 primary operable human breast tumours were collected from six French anticancer centres. The c-erbB-2 protein was measured using an enzymoimmunoassay using two monoclonal antibodies directed against the extracellular domain of the protein. The results were expressed in arbitrary units/mg membrane protein (AU) after adjustment for the anticancer centre. A significant association was found between the dosage of the protein and DNA amplification (P = 0.0001). A value of 200 AU was found to maximise sensibility and specificity and was chosen as a cut-off for over-expression. Significant associations were found between c-erbB-2 values and oestrogen receptor (ER) (P = 0.01), progesterone receptor (PgR) (P = 0.0001) and histological grading (P = 0.01). The extreme high values (above the mean plus one standard deviation, S.D.) were significantly more numerous in ER- (P = 10(-16)), PgR- (P = 10(-14)) and grade III (P = 10(-8)) tumours. The extreme low values (below the mean minus one S.D.) were significantly more numerous in ER- (P = 10(-9)) and PgR- (P = 0.02) tumours. This prospective study confirms that high c-erbB-2 protein values are linked to poor prognostic factors and shows for the first time that low values are also linked to hormone receptor negative tumours, suggesting that these low values might also have a negative prognostic significance.