Clinical outcome and global gene expression data support the existence of the estrogen receptor-negative/progesterone receptor-positive invasive breast cancer phenotype

Estrogen receptor-negative/progesterone receptor-positive breast cancer has distinct characteristics and pathologic complete response rate after neoadjuvant chemotherapy

PURPOSE

The status of hormone receptors (HR) is an independent factor affecting survival and chemotherapy sensitivity in breast cancer (BC) patients, with estrogen receptor (ER) and progesterone receptor (PR) having the most significant effects. The ER-/PR + phenotype has been controversial in BC, and experts will face many challenges in determining treatment strategies. Herein, we systematically analyzed the clinicopathological characteristics of the ER-/PR + phenotype in BC patients and the response to chemotherapy.

PATIENTS AND METHODS

We included two cohorts. The first cohort counted the relationship between clinicopathologic data and survival outcomes for 72,666 female patients in the Surveillance, Epidemiology, and End Results (SEER) database. The second cohort analyzed the relationship between clinicopathological data and pathologic complete response (pCR) rate in 879 patients at the Harbin Medical University Cancer Hospital. The classification data were compared by the chi-square test and Fister's exact test of the Logistic regression model, and predictor variables with P < 0.05 in the univariate analysis were included in the multivariate regression analysis. The Kaplan-Meier method evaluated breast cancer-specific survival (BCSS) and overall survival (OS) to investigate the relationship between different HR typing and survival and pCR.

RESULTS

In the two cohorts, 704 (0.9%) and 11 (1.3%) patients had the ER-/PR + phenotype, respectively. The clinicopathologic features of patients with the ER-/PR + phenotype are more similar to those of the ER-/PR- phenotype. The ER-/PR + phenotype is more common in younger and premenopausal women, and most ER-/PR + phenotypes exhibit higher histological grades. Survival analysis showed that there were significant differences in OS and BCSS among patients with different HR states (P < 0.001). The survival results of patients with the ER + /PR + phenotype were the best. The prognosis of the ER-/PR + phenotype was similar to that of the ER-/PR- phenotype. On the other hand, we found that HR status was also an independent predictor of post-NAC pCR rate in BC patients. The ER + /PR- and ER-/PR- phenotypes were more sensitive to chemotherapy than the ER + /PR + phenotypes.

CONCLUSION

HR status is the main factor affecting BC's survival outcome and pCR rate. Patients with the ER-/PR + phenotype possess more aggressive biological factors and can benefit significantly from chemotherapy. We need to pay more attention to this group and achieve individualized treatment, which will help us treat BC better and provide new targets and blueprints for our clinical treatment.

Hormone receptors in breast cancer: An update on the uncommon subtypes

Breast cancer is the most common cancer affecting women and is the second leading cause of cancer death among US women. Estrogen receptor (ER) signaling plays a crucial role in mammary gland development and carcinogenesis. Near 80 % of invasive breast cancers are ER-positive (ER+). Endocrine therapies targeting ER have significantly improved the prognostic outcomes in the patients with ER+ breast cancer, and the therapeutic effects are strongly correlated with the levels of the ER expression in tumor cells. Despite being an ER-dependent gene product, PR is not always overexpressed in ER+ tumors, and a small subset of breast cancers demonstrates an ER+/PR- phenotype, and a rare ER-/PR+ subtype also exists. There have been controversies on the biology of these tumor types and the predictive and prognostic power of PR status. Compelling data have shown the distinct biologic characteristics of ER+/PR- and ER-/PR+ tumors. Despite that ER-low breast cancers demonstrate more similarity to ER- tumors, at least a subset of ER-low carcinomas may have a functional ER signaling. Thus, adequate PR expression is essential as its absence indicates impaired ER pathway. Assessment of PR status may not only distinguish the ER+/PR- subset from the ER+ and ER-low tumors, but also differentiate the ER-/PR+ phenotype from the ER- carcinomas, both with therapeutic implications. This article was aimed to provide an up-to-date review focusing on the clinicopathologic characteristics of uncommon subtypes of breast cancer, including ER+/PR-, ER-/PR+, and ER-low breast cancers.

Clinicopathological characteristics and prognostic analysis of breast cancer with a hormone receptor status of ER(-)/PR(+)

Background

It is unknown whether ER(-)/PR(+) breast cancer is an independent breast cancer subtype, how it differs from other subtypes, and what its significance is regarding treatment and prognosis. This study compared ER(-)/PR(+) breast cancer with other subtypes to better understand the biological characteristics and prognosis of ER(-)/PR(+) breast cancer, to guide clinical treatment and establish a theoretical foundation.

Methods

We retrospectively analyzed data for patients diagnosed with breast cancer in the Surveillance, Epidemiology, and End Results (SEER) database. The clinicopathological characteristics of ER(-)/PR(+) breast cancer, including age, tumor size, lymph node status, HER-2 status, pathological type and histological grade, were compared with other types of breast cancer. A risk scoring system was developed based on independent risk factors influencing prognosis to predict the patient's prognosis, and a nomogram model was created to predict the patient's survival rate. Receiver operating characteristic curve (ROC) and calibration curve was used to evaluate the predictive performance of the nomogram.

Results

The rates of T3-4, lymph node positivity, HER-2 positivity, infiltrating non-special pathological type, and G3 were significantly higher in ER(-)/PR(+) than in ER(+)/PR(+) cancer (p <0.001). ER(-)/PR(+) was similar to biological activity of ER(-)/PR(-) type. ER(-)/PR(+)/HER-2(+) patients had a better survival prognosis than ER(-)/PR(+) HER-2(-) patients (p<0.05). The prognosis of ER-/PR+ breast cancer was significantly associated with age, HER-2 status, and T stage.

Conclusion

ER(-)/PR(+) breast cancer is more similar to ER(-)/PR(-) breast cancer than other breast cancer subtypes, with an early age of onset, a high proportion of infiltrating non-special types, a high histological grade, and a high HER-2 positivity rate. Whether HER-2 positivity can improve the prognosis of ER(-)/PR(+)breast cancer is worth further discussion. The risk scoring system we developed can effectively distinguish between high-risk and low-risk patients. The nomogram we created had a concordance index of 0.736, and the calibration curve showed good agreement between the predicted and observed outcomes.

A prospective cohort study of clinical characteristics and outcomes in Chinese patients with estrogen receptor-negative/progesterone receptor-positive early breast cancer

PURPOSE

This study aimed to examine the clinical characteristics and outcomes of patients with estrogen receptor-negative (ER-)/progesterone receptor-positive (PR+) early breast cancer. We also aimed to investigate the benefits of adjuvant endocrine therapy (ET) in this patient population.

METHODS

Patients with early breast cancer diagnosed at West China Hospital were divided into the ER-/PR+, ER+, and ER-/PR- groups. The chi-square test was used to analyze differences in clinical and pathological features among the groups. Multivariable Cox and Fine-Gray regression models were used to compare mortality and locoregional recurrence (LRR)/distant recurrence (DR), respectively. We performed a subgroup analysis to determine which ER-/PR+ patients can benefit more from ET.

RESULTS

From 2008 to 2020, we enrolled 443, 7104, and 2892 patients into the ER-/PR+, ER+, and ER-/PR- groups, respectively. The ER-/PR+ group showed more unfavorable clinical features and aggressive pathological characteristics than the ER+ group. The mortality, LRR, and DR rates were higher in the ER-/PR+ than in the ER+ group. Most clinical features and pathological characteristics were similar between the ER-/PR+ and ER-/PR- group and their outcomes were comparable. In the ER-/PR+ group, patients who received ET showed significantly lower LRR and mortality rates than those who did not; however, no difference was observed in DR. Subgroup analysis suggested that ER-/PR+ patients age ≥ 55 years, and postmenopausal status can benefit from ET.

CONCLUSION

ER-/PR+ tumors have more aggressive pathological characteristics and more unfavorable clinical features than ER+ tumors. ET can reduce the LRR and mortality rates in ER-/PR+ patients. Postmenopausal and age ≥ 55 years ER-/PR+ patients can benefit from ET.

Single progesterone receptor-positive phenotype has the similar clinicopathological features and outcome as triple-negative subtype in metastatic breast cancer

Objective

The same clinicopathological features and prognosis have been reported between single progesterone receptor-positive (sPR-positive) and triple-negative phenotype in early-stage breast cancer, but such similarity has not been studied in metastatic breast cancer (MBC). Therefore, the purpose of this study was to estimate the difference between sPR-positive phenotype and other phenotypes in MBC.

Methods

Patients with HER-2-negative MBC were selected from the Surveillance, Epidemiology and End Results database. Pearson's χ2 test was used to compare the difference of clinicopathologic factors between sPR-positive phenotype and other phenotypes. Univariate and multivariate analyses were performed to evaluate the effects of hormone receptor (HoR) phenotypes and other clinicopathologic factors on the cancer-specific survival (CSS) and overall survival (OS).

Results

Overall, 10877 patients including 7060 patients (64.9%) with double HoR-positive (dHoR-positive), 1533 patients (14.1%) with single estrogen receptor-positive (sER-positive), 126 patients (1.2%) with sPR-positive and 2158 patients (19.8%) with double HoR-negative (dHoR-negative) were analyzed. The patients with sPR-positive or dHoR-negative were more likely to be younger, higher grade and tumor stage, visceral and brain metastasis than ER-positive phenotypes (P<0.001). MBC with sPR-positive had the similar CSS (HR: 1.135, 95%CI: 0.909-1.417, P=2.623) and OS (HR: 1.141, 95%CI: 0.921-1.413, P=0.229) as dHoR-negative, but worse outcome than ER-positive phenotypes. Chemotherapy significantly improved the survival for MBC, especially for sPR-positive MBC (CSS, HR: 0.39, 95%CI: 0.213-0.714, P=0.002; OS, HR: 0.366, 95%CI: 0.203-0.662, P=0.001).

Conclusions

Patients with sPR-positive and triple-negative have similar biological behavior and prognosis in MBC. Chemotherapy may be a preferred recommendation for MBC with sPR-positive.

Prognostic Relevance of Estrogen Receptor Status in Circulating Tumor Cells in Breast Cancer Patients Treated With Endocrine Therapy

Recently, female breast cancer (BC) has surpassed lung cancer to occupy the first place of the most commonly diagnosed cancer. The unsatisfactory prognosis of endocrine therapy for breast cancer might be attributed to the discordance in estrogen receptor (ER) status between primary tumors and corresponding metastases, as well as temporal and spatial receptor status heterogeneity at point-in-time between biopsy and treatment. The purpose of this study was to evaluate the prognostic and predictive value of ER status in circulating tumor cells (CTCs) in BC patients. We analyzed ER expression on CTCs isolated using the Pep@MNPs method in 2.0 ml of blood samples from 70 patients with BC and 67 female controls. The predictive and prognostic value of ER expression in CTCs and immunohistochemistry results of biopsies for progression-free survival (PFS) and overall survival (OS) of patients in response to therapies were assessed. The detection rate for CTCs was 95.71% (67/70 patients), with a median of 8 CTCs within 2 ml of peripheral venous blood (PVB). A concordance of 76.56% in ER status between CTCs and corresponding primary tumor and 69.23% between CTCs and corresponding metastases was observed. We also found that patients with ER-positive CTCs (CTC ^ER+) had longer PFS and OS than those without ER-positive CTCs (CTC ^ER-). Our findings suggested that ER status in CTCs of BC patients may provide valuable predictive and prognostic insights into endocrine therapies, although further evaluation in larger prospective trials is required.

Oral Contraceptive Use and Breast Cancer Risk According to Molecular Subtypes Status: A Systematic Review and Meta-Analysis of Case-Control Studies

We conducted a systematic review and meta-analysis to investigate the effect of oral contraceptives (OCs) on risk of breast cancer (BrCa) by status of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). We searched the MEDLINE (PubMed), Embase and the Cochrane Library database and bibliographies of pertinent articles published up to 2020. Therein, we identified nineteen eligible case-control studies which provided data by breast cancer subtypes: ER-positive (ER+), ER-negative (ER−), HER2-positive (HER2+) and Triplet-negative (TN). Summary risk estimates (pooled OR [pOR]) and 95% confidence intervals (CIs) were calculated using fixed/random effects models. The summary meta-analysis showed that over-use of OCs led to significant increased risk of TNBrCa (OR = 1.37, 95% CI; 1.13 to 1.67, p = 0.002), as well as of ER−BrCa (OR = 1.20, 95% CI: 1.03 to 1.40, p = 0.019). There was also a significant reduction in the risk of ER+BrCa (OR = O.92, 95% CI: 0.86 to 0.99, p = 0.026,) and a slight reduction in the risk of HER2+BrCa (OR = 0.95, 95% CI; 0.79 to 1.14, p = 0.561) after taking OCs. Meta-analysis indicated that OC use has different impacts on risk of breast cancer subtypes defined by receptor status. The identified differences between individual subtypes of breast cancer may reflect different mechanisms of carcinogenesis.

Is oestrogen receptor-negative/progesterone receptor-positive (ER-/PR+) a real pathological entity?

Background

The existence of oestrogen receptor-negative (ER−)/progesterone receptor-positive (PR+) breast cancer continues to be an area of controversy amongst oncologists and pathologists.

Methods

To re-evaluate breast cancers originally classified as ER−/PR+ via Oncotype DX® assay and compare molecular phenotype with Recurrence Score® (RS) result, clinicopathologic features and clinical outcomes were retrospectively obtained from electronic health records between January 1998 and June 2005. Archived formalin-fixed, paraffin-embedded (FFPE) tumour specimens were tested for the expression of ER, PR and human-epidermal-growth-factor-2. The number of positive ER−/PR+ samples confirmed by transcriptional analysis was the primary outcome of interest with event-free and overall survival as secondary outcomes. Biopsies from 26 patients underwent Oncotype DX testing and analysis.

Results

Approximately 60% were middle-aged (40–50 years old) women, and 84.6% had invasive ductal carcinoma. Based on the Oncotype DX assay, approximately 65% (N = 17) had ER+/PR+ status; 23% (N = 6) had ER−/PR− status; and 12% had a single hormone positive receptor (1 ER–/PR+, 2 ER+/PR–) status. Almost one-quarter of patients were stratified into the low-RS (<18) or intermediate-RS (18–30) results, and half of the patients had a high-RS (>30) result.

Conclusion

Our findings suggest the ER−/PR+ subtype is not a reproducible entity and emphasises the value of retesting this subtype via molecular methods for appropriate treatment selection and patient outcomes. Multigene assay analysis may serve as a second-line or confirming tool for clinical determination of ER/PR phenotype in breast cancer patients for targeted therapies.

Immunohistochemical and clinicopathologic features of estrogen receptor-negative, progesterone receptor-positive, HER-2 negative breast carcinomas

OBJECTIVE

Currently, there is an ongoing debate whether progesterone receptor positive and estrogen receptor negative breast carcinomas represent a true distinct subtype of tumor or a mere immunohistochemical artifact. In this study, we conducted an immunohistochemistry panel with the antibodies TFF1, EGFR, and CK5 to reclassify this phenotype in a luminal or basal-like subtype.

METHODS

Tumors estrogen receptor -/progesterone receptor +, Her-2 - from a large population of breast cancer patients were selected to be studied. Immunohistochemistry with the antibodies TFF1, EGFR, and CK5 was performed. Tumors showing positivity for TFF1, regardless of EGFR and CK5 results, were classified as luminal-like carcinomas. Those lesions that were negative for TFF1, but were positive for EGFR and/or CK5, were classified as basal-like triple-negative carcinomas. When the three markers were negative, tumors were classified as undetermined. Clinical pathologic characteristics of patients and tumor recurrence were evaluated.

RESULTS

Out of 1188 breast carcinomas investigated, 30 cases (2.5%) presented the estrogen receptor -/progesterone receptor +/HER2- phenotype. Of them, 27 tumors (90%) were classified as basal-like triple-negative carcinomas, one as luminal-like (3.3%), and two as undetermined tumors (6.7%). The mean follow-up for the study group was 27.7 (2.7 to 50) months. Out of the 26 patients, 6 had cancer recurrence: 2 local and 4 systemic recurrences. The average time for recurrence was 17 (8 to 38) months.

CONCLUSION

Estrogen receptor -/progesterone receptor +/tumors exhibit aggressive behavior, similar to triple-negative tumors. An appropriate categorization of these tumors should be made to improve their therapeutic management.

Hormone Receptor Subtype in Ductal Carcinoma in Situ: Prognostic and Predictive Roles of the Progesterone Receptor

Background

We investigated the prognostic and predictive roles of the hormone receptor (HRc) subtype in patients with ductal carcinoma in situ (DCIS). We focused on identifying the roles of the progesterone receptor (PR) independent of estrogen receptor (ER) status.

Methods

Nationwide data of 12,508 female patients diagnosed with DCIS with a mean follow‐up period of 60.7 months were analyzed. HRc subtypes were classified as ER−/PR−, ER−/PR+, ER+/PR−, and ER+/PR+ based on ER and PR statuses. The Cox proportional hazards model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

The ER+/PR+ group showed better prognoses than the ER+/PR− and ER−/PR− groups in the patients who received tamoxifen therapy (p = .001 and p = .031, respectively). HRc subtype was an independent prognostic factor (p = .028). The tamoxifen therapy group showed better survival than the patients who did not receive tamoxifen, but only in the ER+/PR+ subgroup (p = .002). Tamoxifen therapy was an independent prognostic factor (HR, 0.619; 95% CI, 0.423 − 0.907; p = .014). PR status was a favorable prognostic factor in patients with DCIS who received tamoxifen therapy (p < .001), and it remained a prognostic factor independent of ER status (HR, 0.576; 95% CI, 0.349 − 0.951; p = .031).

Conclusion

The HRc subtype can be used as both a prognostic and predictive marker in patients with newly diagnosed DCIS. Tamoxifen therapy can improve overall survival in the ER+/PR+ subtype. PR status has significant prognostic and predictive roles independent of ER status. Testing for the PR status in addition to the ER status is routinely recommended in patients with DCIS to determine the HRc subtype in clinical settings.

Implications for Practice

The hormone receptor (HRc) subtype was an independent prognostic factor, and the estrogen receptor (ER)+/progesterone receptor (PR) + subtype showed a better survival in patients with ductal carcinoma in situ (DCIS) who received tamoxifen therapy. PR was an independent prognostic factor independent of ER, and PR was a favorable prognostic factor in patients with DCIS who received tamoxifen therapy. The HRc subtype could be used as both a prognostic and predictive marker in patients with newly diagnosed DCIS. Testing of PR status in addition to ER status is routinely recommended for patients with DCIS to determine the HRc subtype in clinical settings.

This study investigated the prognostic and predictive roles of the hormone receptor subtype in patients with newly diagnosed ductal carcinoma in situ, focusing on the prognostic and predictive values of progesterone receptor status independent of estrogen receptor status. The prognostic effect of tamoxifen therapy was also investigated

Negative estrogen receptors and positive progesterone receptors breast cancers

CONTEXT

Hormone receptors (estrogen receptor ER and progesterone receptor PR) are prognostic and predictive factors of outcome for invasive breast cancer. Some tumors only express one of these hormone receptors (ER or PR). ER negative/PR positive breast cancer is a rare subtype (1-4 %) and its existence still controversial. The aim of this study was to evaluate characteristics of this group of tumors.

METHODS

We collected data of all consecutive patients managed in our institution for invasive breast cancer between the 1st January 2007 and 31 December 2013. The aim of the study was to compare data of patients with ER-/PR+tumors with the three other subgroups.

RESULTS

Of the 2071 patients included during the study period, 1.2 % were ER-/PR+. These patients were younger than those with the two ER+groups (p<0.0001). The ER-/PR+tumors differed from the ER+groups for several histological prognostic factors: greater histological size (p=0.0004), higher histological grade, more HER2 overexpression/amplification, more association with ductal carcinoma in situ, more lymphovascular invasion, more nodal metastasis (p<0.0001). Chemotherapy was more often used as an adjuvant treatment in addition of endocrine therapy. Survival was equivalent for patients with ER-/PR+tumors and ER+tumors and significantly higher than patients with ER-/PR- tumors (p<0.0001).

CONCLUSION

Women with ER-/PR+breast cancer have worse prognostic factors than women with ER+cancers but have better overall survival than women with ER-/PR- tumors. We may think that the more frequent association of chemotherapy and endocrine therapy is responsible for this better outcome.

Clinical Features and Survival of Single Hormone Receptor-Positive Breast Cancer: A Population-Based Study of 531,605 Patients

PURPOSE

To investigate the prognosis of single hormone receptor-positive (HR⁺) breast cancer (estrogen receptor [ER] positive and progesterone receptor [PR] negative, and ER^-PR⁺) compared to double HR⁺ (ER⁺PR⁺) and double HR^- (ER^-PR^-) tumors.

METHODS

We included 531,605 cases of invasive breast cancer between 1990 and 2012 from the US Surveillance, Epidemiology, and End Results (SEER) database for study and classified cases into 4 phenotypes according to expression of ER and PR: ER⁺PR⁺, ER⁺PR^-, ER^-PR⁺, and ER^-PR^-.

RESULTS

Overall, 66,091 ER⁺PR^- tumors and 9320 ER^-PR⁺ tumors were identified. The clinical characteristics of the ER⁺PR^- group were similar to those of the double HR⁺ group, while those of the ER^-PR⁺ and double HR^- groups were similar. Overall survival of patients with single HR⁺ tumors was intermediate between that of double HR⁺ and double HR^- tumors. However, we observed no differences in disease-specific survival between ER^-PR⁺ and ER^-PR^- patients. In multivariate analysis, outcomes were similar. Relative to the double HR⁺ patient group, risk of death in the ER⁺PR^- group was higher (hazard ratio, 1.422, 95% confidence interval, 1.394-1.452). However, risk of death was comparable between ER^-PR⁺ and ER^-PR^- patients (hazard ratio, 1.03; 95% confidence interval, 0.98-1.08). Multivariate Cox proportional analysis showed that survival times of patients in the younger age bracket (< 60 years), those positive for human epidermal growth factor receptor 2 (HER2), and patients with tumor stage I-III were longer in the ER^-PR⁺ group.

CONCLUSION

Disease-specific survival of single HR⁺ tumor cases was longer than that of double HR^- tumors but poorer than double HR⁺ tumors. However, differences in disease-specific survival were not significant between the ER^-PR⁺ and ER^-PR^- groups.

Long-term prognostic effect of hormone receptor subtype on breast cancer

PURPOSE

To determine the long-term prognostic role of hormone receptor subtype in breast cancer using surveillance, epidemiology, and end results (SEER) database.

METHODS

Data of 810,587 female operable invasive breast cancer patients from SEER database with a mean follow-up period of 94.2 months (range, 0-311 months) were analyzed. Hormone receptor subtype was classified into four groups based on estrogen receptor (ER) and progesterone receptor (PR) statuses: ER(+)/PR(+), ER(+)/PR(-), ER(-)/PR(+), and ER(-)/PR(-).

RESULTS

Numbers of subjects with ER(+)/PR(+), ER(+)/PR(-), ER(-)/PR(+), ER(-)/PR(-), and unknown were 496,279 (61.2%), 86,858 (10.7%), 11,545 (1.4%), 135,441 (16.7%), and 80,464 (9.9%), respectively. The ER(+)/PR(+) subtype showed the best breast-cancer-specific survival, followed by ER(+)/PR(-), ER(-)/PR(+), and ER(-)/PR(-) subtypes in the respective order (all p < 0.001). Survival difference among hormone receptor subtypes was maintained in subgroup analysis according to anatomic stage, race, age group, and year of diagnosis. Hormone receptor subtype was a significant independent prognostic factor in multivariable analyses (p < 0.001). Hazard ratios of ER(+)/PR(-), ER(-)/PR(+), and ER(-)/PR(-) for breast-cancer-specific mortality risk were 1.419 (95% confidence interval [CI] 1.383-1.456), 1.630 (95% CI 1.537-1.729), and 1.811 (95% CI 1.773-1.848), respectively, with ER(+)/PR(+) as reference.

CONCLUSION

Hormone receptor subtype is a significant independent prognostic factor in female operable invasive breast cancer patients with long-term effect. The ER(+)/PR(+) subtype shows the most favorable prognosis, followed by ER(+)/PR(-), ER(-)/PR(+), and ER(-)/PR(-) subtypes in the respective order. Prognostic impacts of hormone receptor subtypes are also maintained in subgroup analysis according to anatomic stage, race, age, and year of diagnosis.

Prognostic role of progesterone receptor expression in a population-based analysis

PURPOSE

The role of progesterone (PR) expression in the management of breast cancer is controversial. The aim of this study is to evaluate the characteristics and prognosis of progesterone status among breast cancers patients in a population-based analysis.

MATERIALS AND METHODS

Through the Tuscan Cancer Registry data on all the invasive breast cancer cases diagnosed during the period 2004-2005 in the provinces of Florence and Prato, central Italy, were retrieved. Histological reports were re-examined to obtain information on the percentage of positive tumor cells for estrogen (ER), progesterone (PR) receptors, Ki67 marker and human epidermal growth factor 2 (HER2). Information on age, stage, differentiation grade were also obtained.

RESULTS

Out of 1487 patients, 28% had PR- breast cancer. These patients were older (p 0.006) than PR+ cancer patients, with more frequently high Ki67 (p < 0.0001), HER2 + (p < 0.0001), ER- (p < 0.0001) tumoral expression. The ER+/PR+ subtype was the most represented (n.1053), while ER-/PR+ was the most rare (n.23); 210 cases (14.1%) ER+ PR- and 201 (13.5%) ER-/PR- cases were found. Analysis of survival by the Cox proportional hazards model showed an independent prognostic value of PR expression (p < 0.0001), also when estrogen, Ki67, HER2 status and age were included. The 5-year cancer-specific survival was 82.1, 86.5, 100, 92% for ER-/PR-, ER+/PR-, ER-/PR+, ER+/PR+ subtype, respectively.

CONCLUSIONS

Our study revealed significant differences in clinicopathological characteristics among breast cancer according to PR expression and confirmed its prognostic independent role, suggesting a role of PR in the improvement of breast cancer prognostic characterization.

Breast cancer subtype discrimination using standardized 4-IHC and digital image analysis

Breast cancer is a heterogeneous disease. Surrogate classification of intrinsic subtypes of invasive carcinomas by combined immunohistochemistry for estrogen receptor (ER), progesterone receptor (PR), HER2, and Ki67 (4-IHC) has increased steadily since the 2011 St Gallen symposium, due to its rapid subtyping of tumors at a reasonable cost. An important step in improving 4-IHC reproducibility and reliability will be to provide reference values from the routine use of standardized 4-IHC followed by image analysis. The aims of the current study were (1) to analyze invasive breast carcinomas using standardized 4-IHC and quantitative image analysis and (2) to compare the results obtained in the classification of biological subtypes using current Ki67 and PR threshold values proposed by different authors to sub-classifying the luminal A-like and the luminal B-like (HER2-negative) subtypes. Five hundred twenty-one tumors were analyzed by standardized immunohistochemistry, with automatic image analysis, and HER2 FISH technique. Positivity for ER was found in 82.7% and for PR in 70.1% of cases. Using the Allred scoring system, hormone receptor results showed a bimodal distribution, particularly for ER. HER2 positivity was found in 15.7% of cases, and the mean Ki67 score was 32.3%. Using the most recently proposed surrogate definitions for the classification of luminal breast cancer subtypes, the percentages of different subtypes that we found were similar to those published with genomic platforms: 40.7% luminal A-like, 32.4% luminal B-like/HER2-negative, 9.8% luminal B-like/HER2-positive, 6.0% HER2-positive, and 11.1% triple negative. Standardized 4-IHC with automatic image analysis constitutes a low-cost method for surrogate definitions of biological subtypes of breast cancer that delivers accurate results in a day.

Multimodal Assessment of Estrogen Receptor mRNA Profiles to Quantify Estrogen Pathway Activity in Breast Tumors

BACKGROUND

Molecular markers have transformed our understanding of the heterogeneity of breast cancer and have allowed the identification of genomic profiles of estrogen receptor (ER)-α signaling. However, our understanding of the transcriptional profiles of ER signaling remains inadequate. Therefore, we sought to identify the genomic indicators of ER pathway activity that could supplement traditional immunohistochemical (IHC) assessments of ER status to better understand ER signaling in the breast tumors of individual patients.

MATERIALS AND METHODS

We reduced ESR1 (gene encoding the ER-α protein) mRNA levels using small interfering RNA in ER⁺ MCF7 breast cancer cells and assayed for transcriptional changes using Affymetrix HG U133 Plus 2.0 arrays. We also compared 1034 ER⁺ and ER^- breast tumors from publicly available microarray data. The principal components of ER activity generated from these analyses and from other published estrogen signatures were compared with ESR1 expression, ER-α IHC, and patient survival.

RESULTS

Genes differentially expressed in both analyses were associated with ER-α IHC and ESR1 mRNA expression. They were also significantly enriched for estrogen-driven molecular pathways associated with ESR1, cyclin D1 (CCND1), MYC (v-myc avian myelocytomatosis viral oncogene homolog), and NFKB (nuclear factor kappa B). Despite their differing constituent genes, the principal components generated from these new analyses and from previously published ER-associated gene lists were all associated with each other and with the survival of patients with breast cancer treated with endocrine therapies.

CONCLUSION

A biomarker of ER-α pathway activity, generated using ESR1-responsive mRNAs in MCF7 cells, when used alongside ER-α IHC and ESR1 mRNA expression, could provide a method for further stratification of patients and add insight into ER pathway activity in these patients.