Steroid receptors, pS2 and cathepsin D in early clinically node-negative breast cancer

pS2 in Breast Carcinoma: Association with Steroid Hormone Receptor Status

AIMS AND BACKGROUND

Knowledge of the steroid hormone receptors has proved to be of significant value in breast cancer. In the present study the possible importance of estrogen-regulated pS2 protein was investigated. Our direct purpose was to answer the question whether the expression of pS2 may be a marker of functional heterogeneity with respect to the steroid hormone receptor status.

METHODS AND STUDY DESIGN

The study included 152 patients with primary, operable, histologically confirmed breast carcinomas. Histology specimens were reviewed and classified according to type, nodal status, tumor size and grade. Steroid hormone receptors were assayed by biochemical methods according to the procedures recommended by the EORTC. pS2 protein measurement was performed in breast carcinoma cytosols using an immunoradiometric assay. The results were analyzed by non-parametric statistical methods.

RESULTS

A statistically significant inverse correlation between pS2 protein expression and histological tumor grade was found. The expression of pS2 protein was confirmed to be correlated with steroid hormone receptor status. However, it is important to point out that in spite of these statistically significant findings there were no significant biological associations due to overlapping individual pS2 protein values. The baseline level of expression of pS2 protein was obtained in histological grade III carcinomas with a negative steroid hormone receptor status. It was shown that the distribution of carcinomas according to the baseline level of pS2 protein expression was heterogeneous among estrogen receptor-positive carcinomas, and strikingly homogeneous among estrogen and progesterone-negative carcinoma.

CONCLUSION

Our study suggested that PR and pS2 protein may identify distinct subsets of estrogen receptor-positive breast carcinomas.

No association between the progesterone receptor gene polymorphism (+331G/a) and the risk of breast cancer: an updated meta-analysis

BACKGROUND

Many published studies have estimated the association between the +331G/A (rs10895068) polymorphism in the progesterone receptor (PgR) gene and breast cancer risk. However, the results remain inconsistent and controversial. To address this inconsistency, we systematically interrogated the aforementioned association via a meta-analysis.

METHODS

Through a literature search, we identified 13 case-control studies, including 12,453 cases and 14,056 case-free controls. The strengths of reported associations were evaluated using odds ratios (ORs) with 95% confidence intervals (95%CIs).

RESULTS

An association was found between +331G/A polymorphism and +331G/A risk in the dominant model (p = 0.027). Via subgroup analysis, we found no association between +331G/A and breast cancer risk in Caucasians, Asians or mixed racial groups.

CONCLUSIONS

Through meta-analysis, we were able to gain insight into previously reported associations between +331G/A polymorphism and breast cancer risk. However, further studies are still needed to provide more evidence.

Pathologic diagnosis of breast cancer patients: evolution of the traditional clinical-pathologic paradigm toward "precision" cancer therapy

We present an updated account of breast cancer treatment and of progress toward "precision" cancer therapy; we focus on new developments in diagnostic molecular pathology and breast cancer that have emerged during the past 2 years. Increasing awareness of new prognostic and predictive methodologies, and introduction of next generation sequencing has increased understanding of both tumor biology and clinical behavior, which offers the possibility of more appropriate therapeutic choices. It remains unclear which of these testing methodologies provides the most informative and cost-effective actionable results for predictive and prognostic pathology. It is likely, however, that an integrated "step-wise" approach that uses the traditional clinical-pathologic paradigms coordinated with molecular characterization of breast tumor tissue, will offer the most comprehensive and cost-effective options for individualized, "precision" therapy for patients with breast cancer.

The role of oestrogen and progesterone receptors in breast cancer - immunohistochemical evaluation of oestrogen and progesterone receptor expression in invasive breast cancer in women

Aim of the study

Expression of oestrogen and progesterone receptors is a very powerful and useful predictor. Because the response rate to hormonal treatment in breast cancer is associated with the presence of oestrogen and progesterone receptors, assessment of the receptor expression profile allows for prediction of breast cancer response to hormonal treatment. The aim of this study was to assess whether the expression of receptors for oestrogen (ER) and progesterone (PR) in the tumour tissue of patients with invasive breast cancer correlated with tumour histological type, histological grade of malignancy, tumour size, and lymph node status.

Material and methods

Materials consisted of histological preparations derived from patients treated for invasive breast cancer. Evaluations were conducted with histopathological and immunohistochemical methods using suitable antibodies.

Results

Among 231 cases of breast cancer 18 invasive lobular carcinomas (ILC) and 213 invasive ductal carcinomas (IDC) were diagnosed. Taking the histological type of tumour into account, oestrogen receptor-positive reaction was observed in 74.2% of IDC and 77.8% of ILC, and the positive response to PR was observed in 67.1% of IDC and 61.1% of ILC. Considering the histological grade, ER- in the largest percentage (72%) was observed in second-grade (G2) invasive carcinomas. Similarly, PR expression (75%) was found in the largest percentage in second-grade (G2) carcinomas. Based on our own studies and data from literature, it appears that the ER (+) status is an indicator of good prognosis, because it points to a less aggressive cancer, in which overall survival and disease-free time is longer in comparison with ER (–) tumours.

Conclusions

Determination of ER status may, therefore, have significant clinical value and is widely used in routine pathological diagnostics.

Estrogen receptors in resistance to hormone therapy

Estrogen and its receptors alpha and beta (ERalpha and ERbeta) play a major role in tumor progression and approximately two-thirds of breast cancers express these functional receptors. Thus, the ER is a major target for current and developing therapies. Although most ER-positive tumors initially respond to hormonal therapies such as tamoxifen, many tumors will eventually become resistant to tamoxifen induced growth inhibition. This chapter will discuss molecular mechanisms that contribute to hormonal resistance of current therapies including ERalpha mutations, the roles of proliferation and apoptosis in tumor homeostasis and receptor coregulator proteins. Additionally, the role of nonclassical ERalpha signaling through growth factor receptors and the subsequent downstream-initiated signaling, and the role of the progesterone receptors will be discussed.

Sulindac Sulfide and Exisulind Inhibit Expression of the Estrogen and Progesterone Receptors in Human Breast Cancer Cells

In previous studies, we found that sulindac sulfide and exisulind (sulindac sulfone, Aptosyn) cause growth inhibition, arrest cells in the G1 phase of the cell cycle, and induce apoptosis in human breast cancer cell lines. These effects were associated with decreased expression of cyclin D1. The present study focuses on the effects of sulindac sulfide and exisulind on hormone signaling components in breast cancer cells. We found that estrogen receptor (ER)-positive and progesterone receptor (PR)-positive T47D breast cancer cells were somewhat more sensitive to growth inhibition by sulindac sulfide or exisulind than ER-negative PR-negative MB-MDA-468 breast cancer cells. Further studies indicated that sulindac sulfide and exisulind caused marked down-regulation of expression of the ER and PR-A and PR-B in T47D cells. However, neither compound caused a major change in expression of the retinoic acid receptor alpha (RARalpha), RARbeta, or RARalpha in T47D cells. Sulindac sulfide and exisulind also caused a decrease in expression of the ER in estrogen-responsive MCF-7 breast cancer cells. Both compounds also markedly inhibited estrogen-stimulated activation of an estrogen-responsive promoter in transient transfection reporter assays. Treatment of T47D cells with specific protein kinase G (PKG) activators did not cause a decrease in ER or PR expression. Therefore, although sulindac sulfide and exisulind can cause activation of PKG, the inhibitory effects of these two compounds on ER and PR expression does not seem to be mediated by PKG. Our findings suggest that the growth inhibition by sulindac sulfide and exisulind in ER-positive and PR-positive human breast cancer cells may be mediated, in part, by inhibition of ER and PR signaling. Thus, these and related compounds may provide a novel approach to the prevention and treatment of human breast cancers, especially those that are ER positive.

Breast cancer patients with progesterone receptor PR-A-rich tumors have poorer disease-free survival rates

PURPOSE

No study has yet analyzed whether changes in relative expression levels of progesterone receptor (PR) isoforms A and B in human breast tumors have significance in predicting clinical outcome. Human PRs are ligand-activated nuclear transcription factors that mediate progesterone action. Their presence in breast tumors is used to predict functional estrogen receptors (ERs) and, therefore, also to predict the likelihood of response to endocrine therapies and disease prognosis. The two PR isoforms, PR-A and PR-B, possess different in vitro and in vivo activities, suggesting that in tumors, the ratio of their expression may control hormone responsiveness. In general, PR-B are strong transcriptional activators, whereas PR-A can act as dominant repressors of PR-B and ER. Thus their balance may affect tamoxifen response in breast cancers.

EXPERIMENTAL DESIGN

To determine whether differential expression of the PR isoforms is associated with clinical outcome and hormonal responsiveness, PR-A and PR-B were measured by immunoblot analysis of cell lysates from 297 axillary node-positive breast tumors.

RESULTS

Expression of the two isoforms correlated with each other, as well as with ER. Additional analyses revealed that patients with PR-positive tumors but high PR-A:PR-B ratios, which were often caused by high PR-A levels, were 2.76 times more likely to relapse than patients with lower ratios, indicating resistance to tamoxifen.

CONCLUSIONS

This study suggests that knowledge of the PR-A:PR-B ratio may identify a subgroup of ER-positive/PR-positive patients with node-positive breast cancer that benefit poorly from endocrine therapy.

Clinicopathological study of the expression of hsp27, pS2, cathepsin D and metallothionein in primary invasive breast cancer

Expression of the hormone-related proteins hsp27, pS2, and also of cathepsin D (CD) and metallothionein (MT) was studied by immunohistochemistry and analyzed against clinical data in breast cancer. Archived material of paraffin-embedded breast carcinoma tissues from a cohort of 134 patients with primary invasive breast cancer was used. Hsp27 and pS2 (>10% of tumor cells stained) were found to be expressed in 63.6% and 37.6% of cases, respectively, and were correlated negatively with grading (P=0.006 and 0.01) and positively with estrogen receptors (ER) (P=0.04 and 0.04). pS2 expression was correlated with lymph node status (P=0.02), tumor size (P=0.01), progesterone receptor (PR) content (P=0.02), hsp27 (P=0.015) and bcl-2 protein (P=0.001). An inverse relationship between pS2 expression and the expression of p53 protein (P=0.005) and proliferation-associated index MIB1 (P<0.0001) was noted. Stromal cathepsin D was positively correlated with tumor grade (P=0.01), PCNA (P=0.007), MIB1 (P=0.001) and p53 (P=0.01), and negatively with ER (P=0.04) and bcl-2 (P<0.0001). MT was correlated positively with stromal CD (P=0.007) and inversely with PgR (P=0.04). Univariate analysis showed CD expression to be a positive prognostic factor for survival (P=0.035), with borderline significance, while MT was more strongly positive (P=0.01). However, none of the proteins studied was found to be related to disease outcome in univariate analysis. Our data show that hsp27, pS2 and stromal CD expression may reflect tumor differentiation and the functional status of ER in breast cancer, but stromal CD and tumor MT expression were the only factors found that may be of limited prognostic value.

Human progesterone receptor gene polymorphism PROGINS and risk for breast cancer in Austrian women

A germline TaqI restriction fragment length polymorphism in the intron G of the progesterone receptor (PR) gene designated PROGINS was described to be associated with an increased risk for ovarian carcinoma. It was supposed that the PR isoform A protein associated with PROGINS has an increased stability and therefore, a higher transcriptional activity. This may cause an inadequate control of estrogen receptor (ER) and PR B isoform and lead to the increased risk of tumor development. On the other hand, loss of heterozygosity (LOH) of the chromosomal region 11q22-23, where the PR gene is located, was frequently observed in breast cancer, suggesting the presence of a tumor suppressor gene in this region. Recently, it was reported that PROGINS is associated with a decreased risk for breast cancer. In order to examine if PROGINS is associated with an alteration of the risk for breast cancer, we examined PROGINS in 155 sporadic breast cancer patients in Austrian women and in a control group of 106 healthy volunteers. LOH affecting the PR gene was also analyzed in the tumor patients. No statistically significant difference was found for the frequencies of the PROGINS carriers (23.2%) in the Austrian breast cancer patients and in the healthy control group (26.4%), indicating that PROGINS is not associated with either an increased or a decreased risk for breast cancer. Furthermore, no associations between the PROGINS status and the protein levels of ER and PR, clinical data like tumor type, differentiation grade, tumor size, and the nodal status as well as the age of the patients were found. There was also no significant difference in the frequency of LOH affecting the PR gene in the PROGINS carriers and non carriers, demonstrating that LOH at PR gene is not associated with the PROGINS status.

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.

Association of in vitro invasiveness and gene expression of estrogen receptor, progesterone receptor, pS2 and plasminogen activator inhibitor-1 in human breast cancer cell lines

The invasive potential of tumor cells is usually tested either by in vitro invasion assays which evaluate cell spreading ability in basement membrane-like matrices or by in vivo invasion assays in nude mice. Both methods are laborious and time-consuming. Tumor invasiveness is accompanied by the changes in expression of various genes. The invasive behavior of cells is therefore represented by certain gene expression patterns. The purpose of this study was to investigate whether expression patterns of several genes are characteristic for the invasiveness of cultured cells. We examined the mRNA levels of estrogen receptor (ER), progesterone receptor (PR), estrogen inducible pS2 and plasminogen activator inhibitor-1 (PAI-1) in 23 cell lines derived from benign and malignant breast tissues using a competitive reverse transcription-polymerase chain reaction (cRT-PCR) system. We also evaluated the invasiveness of these cell lines by their ability to penetrate into a collagen-fibroblast matrix. We demonstrate that the gene expression pattern of breast cell lines is clearly associated with their in vitro invasiveness. In general, cells with ER, PR, pS2 but no PAI-1 expression showed a non-invasive phenotype, while cells expressing PAI-1 mRNA but not ER mRNA are invasive. Our study indicates that the invasiveness of breast cancer cell lines is characterized by PAI-1 gene expression and the lack of ER mRNA. This suggests that PAI-1 may participate in the invasive process.

The relationship between prognostic and predictive factors in the management of breast cancer

The discovery of new prognostic factors proceeds at a much more rapid pace than our knowledge of how to properly utilize this information in the management of patients with breast cancer, especially those with early breast cancer that has not metastasized to regional lymph nodes. Prognostic factors provide information on how the patient is likely to do regardless of treatment. Predictive factors provide information on whether a patient is likely to benefit from therapy. Most factors identified to date provide prognostic information, but relatively few provide information that is truly helpful in making a therapeutic decision in the management of individual patients. In large part this is because there has been insufficient study of the factor, especially prospective evaluations of the factor. Unfortunately this has resulted in the premature use of this information under the general rubric that patients with a poor prognosis deserve more treatment in spite of the fact that there may be no benefit from that therapy in the poor prognostic group.

PS2 mRNA expression adds prognostic information to node status for 6-year survival in breast cancer

Expression of pS2, an oestrogen-regulated gene, has been associated with a good short-term prognosis and response to endocrine therapy. The aim of this study was to determine whether expression of mRNA for the pS2 gene in breast cancer could contribute useful information on disease behaviour and survival at medium-term follow-up. Northern blotting was used to detect pS2 messenger ribonucleic acid (mRNA) in the primary tumour tissue from each of 90 patients with breast cancer. Axillary node status was established by sampling or clearance, oestrogen receptor concentration by enzyme immunosorbant assay and follow-up was continued for at least 6 years or until death. At 83 months mean follow-up, 29 of 90 (32%) patients had recurrent disease and, of these, 18 (20%) had died from breast cancer. pS2 mRNA expression, present in 26 of 90 (29%) cancers, was associated with freedom from disease recurrence (P = 0.026) and was significantly associated with survival at a minimum of 6 years follow-up (P < 0.001). Pathological node status and tumour size were also significantly associated with disease recurrence (P < 0.001 and P = 0.002 respectively) and inversely with survival (P < 0.001 and P < 0.001 respectively). After multiple Cox regression analysis, pS2 expression was still a significant predictor of recurrence (but not survival) after adjusting for node status and tumour size; oestrogen receptor was an independent predictor of survival. The combination of node status and pS2 expression discriminated patients with particularly good prognosis (node negative, pS2 positive: no mortality at 6 years) or poor prognosis (node positive, pS2 negative; 41% mortality at 6 years). Evaluation of pS2 expression in breast cancer at diagnosis may provide additional useful prognostic information to conventional staging.

Cathepsin D in host stromal cells, but not in tumor cells, is associated with aggressive behavior in node-negative breast cancer

One hundred fifty-four axillary lymph node-negative invasive ductal carcinomas of the breast were immunohistochemically evaluated for the expression of cathepsin D. Formalin-fixed paraffin sections of each tumor were stained using a polyclonal antibody raised against recombinant procathepsin D. Cathepsin D content of tumor cells and host histiocytes and fibroblasts within or immediately at the invasive border of tumors were assessed separately and correlated with histomorphology, estrogen-receptor content, and patients' survival data. Positive cathepsin D staining of tumor cells was associated with a lower nuclear grade and well-differentiated histology, whereas moderate to strong staining of host cells correlated with larger tumor size, higher nuclear grade, poorly differentiated histomorphology, and lack of estrogen-receptor (ER) protein. No statistically significant correlation was found between cathepsin D in tumor cells and survival. There was, however, a statistically significant correlation between moderate to strong cathepsin D staining of host cells and shorter disease-free and overall survivals. Expression of cathepsin D by host cells, however, did not have an independent influence on survival. The authors conclude that cathepsin D in stromal cells, but not in tumor cells, is associated with aggressive behavior in node-negative invasive ductal carcinomas of breast. Furthermore, determination of cathepsin D in cytosolic extracts of tumors is of no practical value because it may represent cathepsin D content of tumor cells, intratumoral host cells, or both.

Prognostic value of cathepsin D in breast cancer: comparison of immunohistochemical and immunoradiometric detection methods

AIM

To test whether immunoradiometric or immunohistochemical detection of lysosomal protease cathepsin D in breast cancer is more predictive of outcome.

METHODS

Tumour tissues from 270 primary breast cancer patients were evaluated for the expression of cathepsin D using immunohistochemistry (IH; paraffin embedded tissues) and an immunoradiometric assay (IRMA; cytosol from frozen tissues). Immunohistochemical scores were based on immunoreaction in tumour cells and tumour associated macrophages.

RESULTS

IRMA values (cut off 40 fmol/mg cell protein) correlated significantly with IH values. Recorded incidences of positive immunoreaction in tumour cells using two different cut off values were 52% and 35%, respectively. Macrophages stained positive in 31% of tissues. Combined evaluation of tumour cells and macrophages resulted in positivity rates of 59% and 48%, respectively. Node status was the only variable found to correlate with cathepsin D expression. IH results correlated significantly with clinical outcome (median observation time 68 months) in node negative patients (n = 120) but not in node positive patients (n = 145). Cathepsin D positivity as measured by IRMA was not related to clinical outcome in either group. On multivariate analysis in the node negative group, IH detection of cathepsin D appeared to be the only independent factor indicating prognosis. For node positive patients, tumour grade, size, and receptor status were of prognostic relevance.

CONCLUSIONS

Because of the simple methodology and the minimal amount of tissue used for analysis, immunohistochemistry was preferred to immunoradiometry for cathepsin D measurement; it also provided more predictive data with respect to prognosis.