Loss Of Progesterone Receptor Research Articles

O257: A Transcriptome Analysis of Primary Breast Cancer with Discordant Brain Metastasis Subtype

Abstract Introduction Brain metastasis (BM) occurs in 15-30% of breast cancer (BC) cases. In the era of personalised medicine, knowledge of the BM subtype is of increasing importance. However, there is often discordance between breast primary (BP) subtype and its BM. Improvements in stereotactic radiosurgery and neuroradiology have greatly reduced the number patients undergoing surgical resection. Therefore, identifying BM subtype poses a therapeutic challenge. Methods This study included 116 patients with breast cancer brain metastasis on CTRIAL-IE 09/07. Clinical subtype was evaluated using immunohistochemistry (IHC) results for oestrogen receptor (ER), progesterone receptor (PR) and HER2. 63 BP RNA sequencing (RNA-Seq) samples were analysed to identify differentially expressed genes in ER positive (ER+) primaries that subsequently lost ER in BM vs. ER+ primaries that retained ER. Results 34 (29.3%) of BPs were ER+/HER2- vs. 19 (16.4%) brain metastases, 50 (43.1%) BPs were HER2+ vs. 60 (51.7%) metastases, 32 (27.6%) BPs were TNBC vs. 37 (31.9%) metastases. The most common receptor switches were loss of ER 20/62 (32.36%), loss of PR 17/30 (56.7%) and gain of HER2 11/65 (16.9%). RNA-Seq differential expression analysis of ER+ primary/ER- BM vs. ER+ primary/ER+ BM found ALB, CPA1, GOLGA8G were significantly underexpressed in patients that subsequently lost ER, conversely MUC2, AREG and HSPB1 were significantly overexpressed. Conclusion This study profiles receptor discordance between primary BC and its matched BM. Future studies of differentially expressed genes at a transcript level may predict BM subtype using primary RNA-Seq data and allow for a more tailored treatment approach.

ER+/PR− phenotype exhibits more aggressive biological features and worse outcome compared with ER+/PR+ phenotype in HER2-negative inflammatory breast cancer

The loss of progesterone receptor (PR) often predicts worse biological behavior and prognosis in estrogen receptor-positive (ER +) breast cancer. However, the impact of PR status on inflammatory breast cancer (IBC) has not been studied. Therefore, the purpose of our study was to investigate the influence of PR on IBC. Patients with ER+ and HER2-negative IBC were selected from the Surveillance, Epidemiology and End Results database. Pearson’s χ2 test was used to compare the clinicopathological characteristics between patients with estrogen receptor-positive/progesterone receptor-positive (ER+/PR +) and patients with estrogen receptor-positive/progesterone receptor-negative (ER+/PR−). Univariate and multivariate analyses were performed to investigate the effects of PR status on the breast cancer-specific survival (BCSS) and overall survival (OS) in IBC. Overall, 1553 patients including 1157 (74.5%) patients with ER+/PR+ and 396 (25.5%) patients with ER+/PR− were analyzed in our study. The patients with ER+/PR− were more likely to be high histological grade (p < 0.001) and liver metastasis (p = 0.045) compared to patients with ER+/PR+. Despite higher chance of receiving chemotherapy (83.6% vs 77.3%, P = 0.008), patients with ER+/PR− showed worse BCSS (5-year BCSS rate, 34.3% vs 51.3%, P < 0.001) and OS (5-year OS rate, 31.3% vs 46.1%, P < 0.001) compared with ER+/PR+ phenotype. Multivariate survival analysis showed that patients with ER+/PR− still had worse BCSS (hazard ratios [HR]: 1.764, 95% confidence intervals [CI] 1.476–2.109, P < 0.001) and OS (HR: 1.675, 95% CI 1.411–1.975, P < 0.001) than ER+/PR+ phenotype. Furthermore, patients with ER+/PR− showed worse outcomes than ER+/PR+ phenotype in most subgroups, especially in patients with younger age (≤ 60 years), lower histological grade, lymph node involved and distant metastasis. Patients with ER+/PR− had more aggressive biological behaviors and worse outcomes than patients with ER+/PR+ in IBC. Stronger treatments maybe needed for IBC patients with ER+/PR−.

Study of Biomarker Discordance between Primary and Recurrent Sites and its Clinical Implications in Metastatic Breast Cancer : A Single Institutional Study from India

Immunophenotypic discordance of receptors between primary and metastatic sites significantly impacts treatment outcomes. Current international guidelines recommend rebiopsy of accessible metastatic lesions to reassess tissue biomarkers. While existing literature on biomarker changes is conflicting and heterogeneous, similar studies on the Indian cohort of breast cancer patients are lacking. In this context, we aimed to evaluate the frequencies of biomarker changes between biopsies from primary and recurrent sites, and their association with various clinicopathological characteristics, including the type of metastasis and treatment in metastatic breast cancer (MBC) patients. This is an ambispective study performed at a single center. Immunohistochemical (IHC) expression of paired primary and recurrence samples of MBC patients was reviewed for the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor 2 (HER2), and Ki-67. Concordance, loss, and gain of receptors were assessed based on the Allred scores for ER, PR, and HER2. Ki-67 was assessed based on a 14% cutoff. Further, receptor changes were studied in relation to age, menopausal status, morphology, grade, stage, metastatic sites, interval between biopsies, and treatment. At progression, biopsies were obtained from 41.18% of locoregional recurrence and 58.82% of metastatic sites. Despite high discordance of 47% for ER and 68.6% for PR, true receptor conversion was observed in 9.8%, 21.56%, and 5.88% for ER, PR, and HER2, respectively. There was a significant correlation between age and ER discordance (p = 0.029). Loss in PR significantly correlated with a gain in Ki-67. Of all the metastatic sites, the lung was significantly associated with PR and Ki-67 concordance (p = 0.008 and p = 0.0425, respectively). Discordance of receptors was neither related to the sites of biopsy (local recurrence or metastatic site) nor to the time interval between biopsies, prior chemotherapy, or hormone therapy. In conclusion, metastatic progression of the disease is accompanied by age-dependent discordance of ER. Unparalleled changes in PR in relation to ER suggest that ER-independent pathways may influence PR expression in MBC. Furthermore, the concurrence of PR loss with Ki-67 gain indicates an aggressive phenotype with disease progression. Hence, follow-up testing of samples for receptor expression is beneficial in determining prognosis and guiding therapeutic decisions.

Abstract P6-11-07: Role of insulin resistance in HR+ mammary carcinogenesis

Abstract Hormone receptor (HR+) breast cancer (BC) is responsible for more than 80% BC cases and more than 60% BC-related deaths in the US. The incidence and severity of BC are influenced by a variety of modifiable risk factors, including (but not limited to) nutritional behaviors and obesity. Specifically, women with a body mass index (BMI) &amp;gt; 25 Kg/m2 exhibit an approx. 1.4-fold increase in the risk of developing postmenopausal HR+ BC as compared to women with BMI &amp;lt; 25 Kg/m2. Along similar lines, women with type 2 diabetes (T2D) – one of many consequences of obesity – are at 1.23-fold increased risk to develop postmenopausal HR+ BC as compared to women without T2D. Moreover, a BMI &amp;gt;30 Kg/m2 has been associated with decreased progression-free survival and overall survival (OS) in women with HR+ BC. Thus, a high number of postmenopausal HR+ BC cases and BC-related deaths could be effectively avoided by modifying dietary habits, both in prophylactic and therapeutic settings. Mechanistically, obesity provokes numerous alterations that have been linked to accrued postmenopausal HR+ carcinogenesis, encompassing (1) increased circulating levels of glucose and insulin – reflecting insulin resistance (IR) coupled to T2D, (2) increased levels of estrogen, produced locally and systematically by adipocytes, and (3) chronic inflammation of the breast adipose tissue (AT). However, the relative contribution of IR vs. other obesity-associated alterations to BC development and sensitivity to treatment has not been elucidated. At least in part, this reflects the two most common approaches employed to cause obesity in preclinical studies: the use of high-fat diets (HFDs) and/or mice genetically predisposed to develop obesity (e.g., ob/ob mice), neither of which is suitable to uncouple IR from all other metabolic, hormonal, and inflammatory effects of obesity. Here, we combined a unique model of HR+HER2- carcinogenesis that recapitulates key immunobiological features of human HR+ BC (notably, a cold tumor microenvironment coupled to a scarce sensitivity to immunotherapy, and exquisite sensitivity to CDK4/6 inhibitors), as established in mice by medroxyprogesterone acetate (M) pellets combined with 7,12-dimethylbenz[a]anthracene (D) oral administration, with a novel model of pure IR originating from the AT-specific deletion of RAB10, member RAS oncogene family (Rab10), a transducer of insulin signaling in adipocytes. Importantly, these mice are neither hyperphagic nor overweight, have normal glucose level at baseline and do not exhibit inflammatory alterations in the AT, but nonetheless display IR. While a HFD shortens tumor-free survival (TFS) in immunocompetent mice subjected to M/D-driven oncogenesis, it does not alter the growth of detectable M/D-driven tumors. Conversely, IR as imposed by the loss of Rab10 in the AT failed to alter TFS but accelerated the growth of tumors, resulting in shortened OS. Moreover, the deletion of Rab10 from the mouse AT enabled the development of tumors displaying features of increased aggressiveness, including systematic loss of progesterone receptor (PR) expression. Finally, the growth of tumors emerging in in the context of a Rab10/- AT could be efficiently controlled by the systemic administration of metformin. In line with this notion, orthotopically injected mouse triple negative BC AT-3 cells grew faster in mice bearing an AT-specific deletion of Rab10 as compared to their wild-type littermates. In conclusion, IR as imposed by the loss of Rab10 in the mouse AT converts HR+ mammary carcinomas as driven by M/D into HR- lesions with increased aggressiveness. These findings have major implications for ethnic groups that are at high risk for T2D at BMIs that are considered normal for Caucasians, such as women of African American and Asian descent, especially in view of the fact that women from these ethnic groups are known to be at increased risk for aggressive triple-negative BC as compared to their Caucasian counterparts. Citation Format: Aitziber Buque, Maria Belen Picatoste, Norma Bloy, Lucie Yammine, Rosemary Leahey, Ai Sato, Emma Johnson, Timothy E. McGraw, Lorenzo Galluzzi. Role of insulin resistance in HR+ mammary carcinogenesis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-11-07.

ARID1A Regulates Progesterone Receptor Expression in Early Endometrial Endometrioid Carcinoma Pathogenesis

Loss of progesterone receptor (PR) expression is an established risk factor for unresponsiveness to progesterone therapy in patients with endometrial atypical hyperplasia and endometrioid carcinoma. ARID1A is one of the most commonly mutated genes in endometrioid carcinomas, and the loss of its expression is associated with tumor progression. In this study, we investigated the roles of ARID1A deficiency in PR expression in human and murine endometrial epithelial neoplasia. An analysis of genome-wide chromatin immunoprecipitation sequencing in isogenic ARID1A−/− and ARID1A+/+ human endometrial epithelial cells revealed that ARID1A−/− cells showed significantly reduced chromatin immunoprecipitation sequencing signals for ARID1A, BRG1, and H3K27AC in the PgR enhancer region. We then performed immunohistochemistry to correlate the protein expression levels of ARID1A, estrogen receptor, and PR in 50 human samples of endometrial atypical hyperplasia and 75 human samples of endometrial carcinomas. The expression levels of PR but not were significantly lower in ARID1A-deficient low-grade endometrial carcinomas and atypical hyperplasia (P = .0002). When Pten and Pten/Arid1a conditional knockout murine models were used, Pten−/−;Arid1a−/− mice exhibited significantly decreased epithelial PR expression in endometrial carcinomas (P = .003) and atypical hyperplasia (P < .0001) compared with that in the same tissues from Pten−/−;Arid1a+/+ mice. Our data suggest that the loss of ARID1A expression, as occurs in ARID1A-mutated endometrioid carcinomas, decreases PgR transcription by modulating the PgR enhancer region during early tumor development.

Biomarker Alteration after Neoadjuvant Endocrine Therapy or Chemotherapy in Estrogen Receptor-Positive Breast Cancer.

In estrogen receptor (ER)-positive breast cancer, changes in biomarker expression after neoadjuvant therapy indicate the therapeutic response and are prognostic. However, there is limited information about the biomarker alteration caused by neoadjuvant endocrine therapy in ER-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer. We recruited ER-positive/HER2-negative breast cancer patients who received neoadjuvant chemotherapy (NCT), neoadjuvant endocrine therapy (NET), or sequential neoadjuvant endocrine-chemotherapy (NECT) at Peking University Cancer Hospital from 2015 to 2021. A total of 579 patients had paired immunohistochemistry information in both diagnostic biopsy samples and post-neoadjuvant therapy surgical samples. Through a paired comparison of the immunohistochemical information in pre-treatment and post-treatment samples, we found that progesterone receptor (PR) expression reductions were more frequent than ER expression reductions (70.8% vs. 35.2%) after neoadjuvant therapy. The percentage of patients who had a decreased Ki-67 index in the post-operative samples was similar in the three groups (79.8% vs. 79.7% vs. 78.4%). Moreover, PR losses caused by NET were related to low baseline PR expression (p = 0.001), while we did not find a significant association between PR losses and Ki-67 reductions (p = 0.428) or ER losses (p = 0.274). All three types of neoadjuvant therapies caused a reduction in ER, PR, and Ki-67 expression. In conclusion, we found that PR loss after NET was only significantly related to low baseline PR expression, and there is no significant difference in the extent of prognostic factor change including Ki-67 and ER between the PR loss and non-loss groups.

Breast Cancer MCF-7 Cells Acquire Heterogeneity during Successive Co-Culture with Hematopoietic and Bone Marrow-Derived Mesenchymal Stem/Stromal Cells.

During disease progression and bone metastasis, breast tumor cells interact with various types of bystander cells residing in the tumor microenvironment. Such interactions prompt tumor cell heterogeneity. We used successive co-culture as an experimental model to examine cancer-bystander cell interaction. RMCF7-2, a clone of the human breast cancer MCF-7 cells tagged with a red fluorescent protein, was tracked for morphologic, behavioral, and gene expression changes. Co-cultured with various types of hematopoietic cells, RMCF7-2 adopted stable changes to a rounded shape in suspension growth of red fluorescent cells, from which derivative clones displayed marked expressional changes of marker proteins, including reduced E-cadherin and estrogen receptor α, and loss of progesterone receptor. In a successive co-culture with bone marrow-derived mesenchymal stem/stromal cells, the red fluorescent clones in suspension growth changed once more, adopting an attachment growth, but in diversified shapes. Red fluorescent clones recovered from the second-round co-culture were heterogeneous in morphology, but retained the altered marker protein expression while displaying increased proliferation, migration, and xenograft tumor formation. Interaction with bystander cells caused permanent morphologic, growth behavioral, and gene expressional changes under successive co-culture, which is a powerful model for studying cancer cell heterogeneity during breast cancer progression and metastasis.

Abstract 5951: Synergistic efficacy of sulforaphane and progesterone against endometrial cancer

Abstract Introduction: Worldwide, endometrial cancer (EC) is the most common gynecological malignancy with increasing rate of incidence and mortality. While progesterone-based hormone therapy is a well-accepted conservative therapeutic option for EC patients, loss of progesterone receptor (PR) in long-term treatment leading to hormonal resistance and disease recurrence is still an area of concern. We demonstrated potent anti-cancerous activity of sulforaphane against EC in vitro and in vivo and hypothesized that it will activate PR and overcome progesterone therapy limitations. The purpose of this study was to evaluate the interaction of sulforaphane and progesterone against EC. Methods: The in vitro synergistic interaction between sulforaphane and progesterone was investigated with isobologram analysis of plotting MTT metabolic viability assay results of EC cells treated with drugs individually and in combination using CompuSyn software. ATP, soft-agar colony formation and invasion assays were performed to evaluate the combined drug effects on cell viability, anchorage independent colony formation and invasion properties, respectively. Mitochondrial membrane potential and caspase-3 activity were measured by JC-1 and caspase-3 detection ELISA kit, respectively. Protein expression was accessed by western blot. Progesterone resistant EC cells were developed by treating cells with 30µM of progesterone for more than 3 months. Results: Sulforaphane demonstrated strong synergy or additive effects with progesterone in the EC cell lines tested. Sulforaphane in combination with progesterone significantly decreased levels of cellular ATP, anchorage-independent colony formation, invasion and mitochondrial membrane potential. Furthermore, combination of sulforaphane and progesterone increased caspase-3 activity as compared to individual drug or controls, suggesting induction of apoptosis. Western blot results demonstrated an increased expression of cleaved PARP, with reduced expression of total caspase-3 and PCNA in the combination groups as compared to control and individual drugs. Sulforaphane alone or in combination showed increased expression of PR-A while it had minimal effects on PR-B. Further, in all EC cell lines, the combination of sulforaphane and progesterone demonstrated upregulation of PR-A/PR-B ratio. The progesterone resistant cells demonstrated less sensitivity to progesterone as compared to parent cell lines, however it was found to be sensitive to sulforaphane. Conclusions: Sulforaphane demonstrated synergistic activity with progesterone leading to increased apoptosis and reduced proliferation. Furthermore, sulforaphane exhibited potent toxicity to progesterone resistance cells. Sulforaphane in combination with progesterone could overcome progesterone therapy limitation by re-activation of PR. Funding: Administrative Suppl (P30CA225520) and PHF (GRF00005456) Citation Format: Rajani Rai, Swati Choudhary, Doris M. Benbrook, Vishal Chandra. Synergistic efficacy of sulforaphane and progesterone against endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5951.

Quantitative Measurement of Progesterone Receptor Immunohistochemical Expression to Predict Lymph Node Metastasis in Endometrial Cancer.

Background: Previous studies have shown that loss of progesterone receptor (PR) in endometrial cancer (EC) is associated with poor outcomes. Evaluating lymph node metastasis (LNM) is essential, especially before surgical staging. The aim of this study was to investigate the role of PR expression and other clinicopathological parameters in LNM and to develop a prediction model. Methods: We retrospectively evaluated endometrioid-type EC patients treated with staging surgery between January 2015 and March 2020. We analyzed PR status using immunohistochemical staining, and the expression was quantified using the H-score. We identified optimal cut-off values of H-score and CA125 for predicting LNM using receiver operating characteristic curves, and used stepwise multivariate logistic regression analysis to identify independent predictors. A nomogram for predicting LNM was constructed and validated using bootstrap resampling. Results: Of the 310 patients evaluated, the optimal cut-off values of PR H-score and CA125 were 162.5 (AUC 0.670, p = 0.001) and 40 U/mL (AUC 0.739, p < 0.001), respectively. Multivariate analysis showed that CA125 ≥ 40 U/mL (OR: 8.03; 95% CI: 3.44–18.77), PR H-score < 162.5 (OR: 5.22; 95% CI: 1.87–14.60), and tumor grade 2/3 (OR: 3.25; 95% CI: 1.33–7.91) were independent predictors. These three variables were incorporated into a nomogram, which showed effective discrimination with a concordance index of 0.829. Calibration curves for the probability of LNM showed optimal agreement between the probability as predicted by the nomogram and the actual probability. Our model gave a negative predictive value and a negative likelihood ratio of 98.4% and 0.14, respectively. Conclusions: PR H-score along with tumor grade and CA125 are helpful to predict LNM. In addition, our nomogram can aid in decision making with regard to lymphadenectomy in endometrioid-type EC.

SWI/SNF Antagonism of PRC2 Mediates Estrogen-Induced Progesterone Receptor Expression.

Endometrial cancer (EC) is characterized by high estrogen levels unopposed by progesterone. Treatment with progestins is standard for early EC, but the response to progestins is dependent on progesterone receptor (PGR) expression. Here, we show that the expression of PGR in endometrial epithelial cells is dependent on ARID1A, a DNA-binding subunit of the SWI/SNF chromatin-remodeling complex that is commonly mutated in EC. In endometrial epithelial cells with estrogen receptor overexpression, we find that ARID1A promotes estrogen signaling and regulates common gene expression programs. Normally, endometrial epithelial cells expressing estrogen receptors respond to estrogen by upregulating the PGR. However, when ARID1A expression is lost, upregulation of PGR expression is significantly reduced. This phenomenon can also occur following the loss of the SWI/SNF subunit BRG1, suggesting a role for ARID1A- and BRG1-containing complexes in PGR regulation. We find that PGR is regulated by a bivalent promoter, which harbors both H3K4me3 and H3K27me3 histone tail modifications. H3K27me3 is deposited by EZH2, and inhibition of EZH2 in the context of ARID1A loss results in restoration of estrogen-induced PGR expression. Our results suggest a role for ARID1A deficiency in the loss of PGR in late-stage EC and a therapeutic utility for EZH2 inhibitors in this disease.

Abstract P3-12-14: Attenuated negative prognostic effect of progesterone receptor negativity in postmenopausal ER+ breast cancer with normal BMI (&amp;lt;25): A nation-wide study in Korean Breast Cancer Society and the institutional cohort

Abstract Purpose Loss of progesterone receptor (PR) expression is a poor prognostic factor in ER+/HER2- breast cancer. A growing body of evidence suggests that PR expression is affected by endogenous estrogen level and modulated by body mass index (BMI). Using Korean Breast Cancer Society Registry (KBCSR) and institutional database, we evaluated survival outcome by PR expression in the postmenopausal groups stratified by BMI. Moreover, we investigated 21-gene recurrence score to assess intrinsic tumor biology. Method Data from the KBCSR for patients diagnosed with invasive breast cancer when aged over 50 years were reviewed, and 33,314 with BMI were included. Of these, we investigated overall survival (OS) of women at age of 60 and older with a median follow-up of 56 months (n=9,492). In the institutional cohort with ER+HER2- breast cancer women at age of 50 and older (n=703), the landmark survival analyses were performed to address the 5-years recurrence-free survival (RFS). In the subset of the institutional cohort, 21-gene recurrence scores were identified in individuals (n=470). Normal weight is defined as BMI less than 25kg/m2. Result Among the postmenopausal women from the KBCSR, the PR- was significantly associated with adverse OS (hazard ratio [HR], 1.39; 95% CI, 1.16-1.67; p&amp;lt;0.001) in high BMI group (≥25) whereas in normal BMI group (&amp;lt;25) did not (HR, 1.07; 95% CI, 0.89-1.29; p=0.498) (interaction p=0.046). In the institutional cohort with ER+/HER2- postmenopausal women (age&amp;gt;50), RFS was superior in the PR+ than in the PR- in the postmenopausal with high BMI (≥25). In contrast, RFS was not separated by PR in the normal BMI group (&amp;lt;25). When we compared the 21-gene recurrence score according to PR, the scores were significantly lower in the PR+ than in the PR- regardless of BMI. Conclusion In ER+/HER2- aged postmenopausal breast cancer women with normal BMI who have low estrogen environment, negative prognostic effect of absence of PR expression is attenuated. Bad tumor biology of PR- cancer is conserved irrespective of BMI. We support the hypothesis that weight control to reduce endogenous estrogen produced by adipose tissue is beneficial for postmenopausal women with ER+ breast cancer. Citation Format: Soong June Bae, Jawon Hwang, Janghee Lee, Jung Hwan Ji, Chihhao Chu, Jee Hung Kim, Sung Gwe Ahn, Joon Jeong. Attenuated negative prognostic effect of progesterone receptor negativity in postmenopausal ER+ breast cancer with normal BMI (&amp;lt;25): A nation-wide study in Korean Breast Cancer Society and the institutional cohort [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-12-14.

Lost but Not Least-Novel Insights into Progesterone Receptor Loss in Estrogen Receptor-Positive Breast Cancer.

Simple SummaryMost breast cancers co-express estrogen receptor α (ERα) and progesterone receptor (PgR). These cancers are sensitive to endocrine therapy and, in general, have superior outcomes. However, a subset of tumors expresses ERα but loses expression of PgR in various mechanisms. The processes driving the loss of PgR may cause resistance to hormonal treatment and a more aggressive clinical course. The current review summarizes current knowledge on the biology of ERα-positive PgR(−)negative breast cancer and discusses the associations between molecular mechanisms and clinical characteristics.Estrogen receptor α (ERα) and progesterone receptor (PgR) are crucial prognostic and predictive biomarkers that are usually co-expressed in breast cancer (BC). However, 12–24% of BCs present ERα(+)/PgR(−) phenotype at immunohistochemical evaluation. In fact, BC may either show primary PgR(−) status (in chemonaïve tumor sample), lose PgR expression during neoadjuvant treatment, or acquire PgR(−) phenotype in local relapse or metastasis. The loss of PgR expression in ERα(+) breast cancer may signify resistance to endocrine therapy and poorer outcomes. On the other hand, ERα(+)/PgR(−) BCs may have a better response to neoadjuvant chemotherapy than double-positive tumors. Loss of PgR expression may be a result of pre-transcriptional alterations (copy number loss, mutation, epigenetic modifications), decreased transcription of the PGR gene (e.g., by microRNAs), and post-translational modifications (e.g., phosphorylation, sumoylation). Various processes involved in the down-regulation of PgR have distinct consequences on the biology of cancer cells. Occasionally, negative PgR status detected by immunohistochemical analysis is paradoxically associated with enhanced transcriptional activity of PgR that might be inhibited by antiprogestin treatment. Identification of the mechanism of PgR loss in each patient seems challenging, yet it may provide important information on the biology of the tumor and predict its responsiveness to the therapy.

The rate of estrogen receptor-conversion associated with tumor progression in estrogen receptor-positive breast cancer patients following adjuvant Tamoxifen administration.

BackgroundHormone Receptor (HR)‐discordance between primary breast cancer and metastasis is a known biological phenomenon. Discordance studies usually comprise a heterogeneous group of HR‐positive and negative patients and allow for the comparison of changes in HR‐status from the primary to the recurrent disease. However, in a clinical setting, the rate of estrogen receptor‐conversion following endocrine therapy with agents such as Tamoxifen (TAM) in estrogen receptor‐positive cancers is of primary interest as opposed to total receptor discordance.AimTo investigate the rate of estrogen receptor‐conversion associated with tumor progression in estrogen receptor‐positive breast cancer patients following adjuvant TAM administration and to compare the results with the meta‐analysis data of HR‐discordance studies.Methods and ResultsA retrospective double‐center review of biomarkers in 67 estrogen receptor‐positive breast cancer patients who underwent TAM treatment in the adjuvant setting. The estrogen and progesterone receptor‐status were compared at the time of diagnosis and following relapse and the Disease‐free Survival, mean duration of TAM treatment as well as the operative, radiation, and cytotoxic therapies registered before TAM treatment, were recorded.Initially, all patients were estrogen receptor‐positive. The average age at the time of diagnosis was 52.8 ± 12.4 years. After recurrence, only 47 patients (70.1%) were still estrogen receptor‐positive with a highly significant loss of estrogen receptor‐expression in 29.9% of cases. The mean duration of TAM treatment was 40.7 ± 19.9 months. 45 patients (i.e., 67.2%) progressed during the TAM treatment and the remaining 22 patients (32.8%) developed relapse after the TAM treatment had finished. Initially, there were 82.1% progesterone receptor‐positive and 17.9% progesterone receptor‐negative, but after relapse the progesterone receptor‐positive cases diminished significantly to 53.7%, showing a progesterone receptor‐loss of 28.4%.ConclusionThe rate of estrogen receptor‐loss associated with tumor progression following TAM treatment is approximately 30%, which is of clinical relevance in order to evaluate further endocrine efficacy in these patients. This rate of receptor conversion is roughly 6‐13% higher compared to the recently published meta‐analysis data of discordance studies. This discrepancy could possibly be due to anti‐hormonal therapy with TAM accentuating receptor conversion.

Abstract PS5-37: The feasibility of obtaining oncotype DX breast recurrence score® results from metastatic sites of patients with hormone receptor positive metastatic breast cancer

Abstract Background: Identifying when to start CDK4/6 inhibitors or use chemotherapy in hormone receptor positive (HR+) metastatic breast cancer (MBC) remains challenging. The 21-gene Oncotype DX Breast Recurrence Score® test is validated to predict chemotherapy benefit in early stage HR+ breast cancer but has not been studied for use in the MBC setting.Objective: To assess the feasibility of obtaining Recurrence Scores from metastatic sites after standard of care biopsy in HR+, HER2 negative patients and correlate Recurrence Score results from matched primary breast cancer when available. Methods: A total of 48 metastatic biopsies were retrieved retrospectively from the residual tissue of patients with primary HR+, HER2 negative breast cancer. This included 36 from bone and 12 from other sites [liver (7), lung (1), rectum (1), brain (1), skin (2)]. Slides were sent to Genomic Health Inc. for RNA isolation and Recurrence Score result determination using standardized protocols. Recurrence Score results were available for 18 matched primary and metastatic biopsy samples. The percent success rate for Recurrence Score result was determined for the various metastatic sites and results compared between matched primary and metastatic site. Results: Recurrence Score results were obtained in 48% of metastatic biopsies (23 of 48 samples) including bone (17), liver (4), lung (1), and skin (1). Reasons for Recurrence Score failure included insufficient RNA (17), poor quality RNA (1), failed QC (4), and other (3). The mean Recurrence Score from the 23 metastatic sites was 35 (range: 1–66). Notably, 70% (16/23) of successful metastatic biopsies yielded Recurrence Scores in the high-risk range (&amp;gt;25). None of the 23 metastatic biopsies gained HER2 by RT-PCR. Among the 18 paired samples, higher recurrence score results were observed in all but three of the metastatic biopsy samples with mean Recurrence Score results of 20 (range 7 to 41) for the primary and 35 (range 1-66) for the metastatic site. For paired samples, 72% of metastatic biopsies yielded Recurrence Scores &amp;gt;25 compared to 17% of primary sample. Primary Recurrence Scores were not predictive of metastatic scores (r2=0.052). Estrogen receptor (ER) expression status was conserved in 87% whereas progesterone receptor (PR) was lost in 69% of the metastatic lesion. Among the pairs, 5 had de novo metastatic disease. In these, the Recurrence Score was higher in the metastatic biopsy in each case compared to the matched primary (mean 36 versus 23, respectively). Among de novo cases, there was 100% concordance in ER positive and HER2 negative expression and only 60% concordance in PR expression between primary and metastatic sites. Conclusion: Using standard of care metastatic biopsy samples, a Recurrence Score result was successfully generated in 48% of samples including bone. This small series demonstrates wide variability in Recurrence Score results in metastatic disease with overall higher scores, common loss of PR, and minimal correlation to matched primary disease. Further examination of the potential significance of the Recurrence Score for treatment decisions in the metastatic setting requires additional tissue sampling during biopsy as insufficient RNA was the primary reason for failure. Citation Format: Julie Anne L Gemmill, Patricia Thompson, Rebecca Batiste, Caterina Vacchi-Suzzi, Christina Preece, Jules Cohen, Lea Baer, Carolyn Mies, Michelle Turner, Christy A Russell, Alison Stopeck. The feasibility of obtaining oncotype DX breast recurrence score® results from metastatic sites of patients with hormone receptor positive metastatic breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS5-37.

BIOM-51. FACTORS ASSOCIATED WITH DECLINING SEX DISCREPANCY IN MENINGIOMA WITH INCREASING TUMOR AGGRESSIVENESS: RETROSPECTIVE REVIEW OF A RURAL PENNSYLVANIA COHORT

Abstract INTRODUCTION Meningioma is the most common benign primary brain tumor in adults comprising 37% of all primary CNS tumors. Approximately 81.1% of meningiomas are grade I, 16.9% - grade II, and 1.7% - grade III. While females are 2.5 times more likely to have meningiomas, males more commonly have aggressive grades. Loss of progesterone receptor (PR) and presence of androgen receptor (AR) are associated with tumor aggressiveness. We observed a declining sex-discrepancy with increasing tumor grade. We present an ongoing assessment of a rural population to define potential factors contributing to this observation. METHODS We completed a single institutional retrospective review of 406 pathology confirmed meningiomas in rural Northeast Pennsylvania. We compared WHO grade, hormone receptors, and proliferative indices between males and females. We further evaluated tumor location and comorbid endocrine disease for possible association. RESULTS Our patient cohort had a high frequency of aggressive tumors 73.5% (n= 297) grade I, 24% (n= 99) grade II, and 2.5% (n= 10) grade III. The ratio of females versus males was 3.1:1, 1.3:1, and 1:1 in grades I, II, and III respectively. Factors contributing to closing the sex-gap were: (1) grade II: males expressed less PR than females (76% vs 94%); (2) grade III: females expressed less AR than males (0% vs 100%), while PR expression remained equivalent; and (3) males had higher tumor proliferative indices compared to females (7% and 22% vs 2% and 14%), grades I and II respectively. There was no relationship determined for tumor location or comorbid endocrine disease between the sexes. CONCLUSION The association between declining sex discrepancy in meningioma with increasing tumor aggressiveness is potentially related to the expression PR, AR, and increased tumor proliferation indices with increasing meningioma grade.

Loss of progesterone receptor is associated with distinct tyrosine kinase profiles in breast cancer

PurposeThe aim of this study was to assess protein tyrosine kinase profiles in primary breast cancer samples in correlation with the distinct hormone and growth receptor profiles ER, PR, and HER2.Experimental designPamchip® microarrays were used to measure the phosphorylation of 144 tyrosine kinase substrates in 29 ER+ breast cancer samples and cell lines MCF7, BT474 and ZR75-1. mRNA expression data from the METABRIC cohort and publicly available PR chip-sequencing data were used for validation purposes, together with RT-PCR.ResultsIn ER+ breast tumors and cell lines, we observed that the loss of PR expression correlated to higher kinase activity in samples and cell lines that were HER2−. A number of kinases, representing mostly proteins within the PI3K/AKT pathway, were identified as responsible for the differential phosphorylation between PR− and PR+ in ER+/HER2− tumors. We used the METABRIC cohort to analyze mRNA expression from 977 ER+/HER2− breast cancers. Twenty four kinase-encoding genes were identified as differentially expressed between PR+ and PR−, dividing ER+/HER2− samples in two distinct clusters with significant differences in survival (p < 0.05). Four kinase genes, LCK, FRK, FGFR4, and MST1R, were identified as potential direct targets of PR.ConclusionsOur results suggest that the PR status has a profound effect on tyrosine kinases, especially for FGFR4 and LCK genes, in ER+/HER2− breast cancer patients. The influence of these genes on the PI3K/AKT signaling pathway may potentially lead to novel drug targets for ER+/PR− breast cancer patients.

Abstract B26: The natural history of ovarian high-grade serous carcinoma from time effects of ovulation inhibition and progesterone clearance of p53-defective lesions

Abstract High-grade serous carcinoma (HGSC) is the most common and devastating type of ovarian cancer; its etiology, mechanism of malignant transformation, and origin remain controversial. Recent studies have identified secretory cells at the fimbria of the fallopian tube as the cell of origin of HGSC, initiating TP53 mutation, evolving to tubal precursor lesions, including “p53 signature” and serous tubal intraepithelial carcinoma (STIC), and metastasizing to the ovary as clinically evident ovarian cancer. The etiologic mechanisms associated with the known epidemiologic risk factors, i.e., ovulation and retrograde menstruation, have also been unveiled. Mutagens and transforming growth factors, such as reactive oxygen species and IGF axis proteins, as well as the apoptosis-rescuing protein hemoglobin are abundantly present in the ovulatory follicular fluid and peritoneum fluid, which bathes the fimbrial epithelium, and induces malignant transformation after repeated exposure. Meanwhile, in accordance with the proposed therapeutic effect of progesterone from studies on oral contraceptive (OC) use or term pregnancy, our recent study indicated that the p53-null tubal epithelial cells are selectively cleared by progesterone depending on its progesterone receptor (PR). In this report, by analyzing different time-effects of OC use or pregnancy in the prevention of ovarian cancer and by aligning them with the carcinogenic and therapeutic clearance concepts of ovulation and P4, as well as the fact of progressive loss of PR during tubal transformation, we deduced the natural history of ovarian HGSC. The natural history begins at the first ovulation and spans more than 30 years, taking 10 years from the normal tubal epithelium to the “p53 signature” status, another 15 years to PR(-) STIC, and a final 5+ years to HGSC. The estimated natural history may help understand the pathogenesis of HGSC and defines the window for early detection and chemoprevention. Citation Format: Tang-Yuan Chu, Na-Yi Yuan Wu, Jing Wang. The natural history of ovarian high-grade serous carcinoma from time effects of ovulation inhibition and progesterone clearance of p53-defective lesions [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B26.

Prognostic significance of hormone receptor (ER/PR) status in endometrial carcinoma in black women: Implications with lymph node metastasis.

e18099 Background: Histological examination of tumor tissues is necessary for deciding if endometrial surgery should include lymph node sampling. Studies have demonstrated that loss of estrogen and progesterone receptors (ER/ PR) independently predicts lymph node metastasis and poor prognosis. African American females in comparison to their Caucasian counterparts are diagnosed at a later stage, with higher grade, poorer prognostic histological types and worse outcomes. Our study aimed to investigate if the correlation between hormone receptor status and lymph node metastasis holds true in African American females which could aid in treatment strategies. Methods: We reviewed African American females (n = 70) diagnosed with Endometrial Cancer at our institution from 2015-2018 including endometrioid/non-endometrioid histology, FIGO stage I-IV, grade 1-3 for ER/PR receptors and presence or absence of pelvic lymph nodes based on preoperative endometrial curettage and post-surgical pathology specimens. Statistical analyses were performed using Fisher’s Exact test exploring associations between categorical variables (ER/PR and Lymph nodes Metastasis). All statistical tests were two-sided and considered significant if P value &lt; 0.05. Results: The mean age of our sample was 61 ± 13 years. Mean BMI was 36±10kg/m2. Majority of our patients were postmenopausal (59 out of 70, 84%). FIGO Stage 1 and 2 constituted 72% (50 out of 70). Endometrioid histology constituted 39 out of 70 (55%) cases and non-endometrioid histology which includes serous, mixed and carcinosarcomas constituted 45% of the cases. Loss of estrogen receptor(ER-) was observed in 19 of 70 patients (27%) and loss of progesterone receptor(PR-) was seen in 22 patients (31%) which was significantly associated with lymph node metastasis (p value &lt; 0.05).On subgroup analyses significant association was observed between PR+ and absence of lymph node metastasis in cases of endometrioid cancer (p value &lt; 0.05) . Nevertheless, there was no statistical significant association (P value .10) between ER receptors and lymph node metastasis in patients with endometrioid cancer. In non-endometrioid histology both ER- and PR- were found to have statistical significant lymph node involvement. Conclusions: Loss of ER and PR receptors independently predicts lymph node metastasis in endometrial cancers in African American females.

Maternal recognition of pregnancy signal or endocrine disruptor: The two faces of oestrogen during establishment of pregnancy in the pig

Timing of conceptus growth and attachment to the uterine luminal epithelium is regulated by progesterone secretion from the corpus luteum and by expression of progesterone receptor in the uterine epithelia and stroma. Conceptus growth and uterine attachment are temporally associated with the disappearance of progesterone receptors from uterine epithelia. While the loss of progesterone receptor from the endometrial epithelia on day 10 of the oestrous cycle and pregnancy has been well documented, the factors involved with cell specific down-regulation of progesterone receptor are yet to be established. We propose that several progesterone stimulated factors activate nuclear factor kappa B (NF-kB) within the uterine epithelia, which leads to inhibition of progesterone receptor and concomitant stimulation of endometrial genes expressed during early conceptus development. Although oestrogens secreted by pig conceptuses function to establish pregnancy, timing of endometrial exposure to oestrogen is critical. Early oestrogen administration alters the pattern of gene expression through the NF-kB system desynchronising the uterine environment for conceptus implantation resulting in later embryonic loss.

Natural history of ovarian high-grade serous carcinoma from time effects of ovulation inhibition and progesterone clearance of p53-defective lesions.

High-grade serous carcinoma is the most common and devastating type of ovarian cancer; its etiology, mechanism of malignant transformation, and origin remain controversial. Recent studies have identified secretory cells at the fimbria of the fallopian tube as the cell-of-origin of high-grade serous carcinoma, acquiring TP53 mutation, evolving to tubal precursor lesions, including "p53 signature" and serous tubal intraepithelial carcinoma, and metastasizing to the ovary as clinically evident ovarian cancer. The etiological mechanisms associated with known epidemiological risk factors, i.e., ovulation and retrograde menstruation, have also been suggested. Mutagens and transforming growth factors, such as reactive oxygen species and insulin-like growth factor axis proteins, as well as the apoptosis-rescuing protein hemoglobin are abundantly present in the ovulatory follicular fluid and peritoneum fluid, which bathes the fimbrial epithelium, and induces malignant transformation after repeated exposure. In accordance with the proposed cleansing effect of progesterone from studies on oral contraceptive use or term pregnancy, a recent study indicated that the p53-null tubal epithelial cells are selectively cleared by progesterone depending on its progesterone receptor. In this report, by analyzing different time effects of oral contraceptive use or pregnancy in the prevention of ovarian cancer and by aligning them with the carcinogenic and cleansing clearance concepts of ovulation and progesterone, as well as the fact of progressive loss of progesterone receptor during tubal transformation, we deduced the natural history of ovarian high-grade serous carcinoma. The natural history begins at the first ovulation and spans for more than 30 years, taking 10 years from the normal tubal epithelium to the "p53 signature" status, another 15 years to progesterone receptor negative serous tubal intraepithelial carcinoma, and a final 5+ years to high-grade serous carcinoma. The estimated natural history may help understand the pathogenesis of high-grade serous carcinoma and defines the window for early detection and chemoprevention.