Progesterone Receptor Levels Research Articles

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.

Rhizoma Drynariae Improves Endometrial Receptivity in a Mus Model of Dysfunctional Embryo Implantation

Background: Rhizoma drynariae is a traditional Chinese medicine used in orthopedics and traumatology, but its effect on endometrial receptivity remains unknown. Aims and Objectives: To observe effect of Rhizoma drynariae and its main components on endometrial receptivity in a mus model of dysfunctional embryo implantation. Materials and Methods: Mus models were established by the GnRHa+HMG+HCG method. Normal mus receiving saline were used as controls and the remaining six groups were: model receiving saline, progynova, aspirin, Rhizoma drynariae, osteopractic total flavone, and naringin. Pinopodes in uterine endometrium were examined by scanning electron microscopy. Stem cell factor (SCF) mRNA expressions was determined by real-time RT-PCR, and estrogen receptor α (ERα), progesterone receptor (PR) by immunohistochemistry. Results: In the model group, surface morphology of endometrium was heterogeneous, without obvious pinopodes. In the Rhizoma drynaria and progynova groups, pinopodes were abundant. Compared with the blank group, model group had lower levels of SCF (-47%), ERα (-63%) and PR (-50%) (all P&lt;0.05). In comparison, Rhizoma drynariae group had higher levels of SCF (+73%), ERα (+118%) and PR (+101%) (all P&lt;0.01). The individual main components of Rhizoma drynariae had variable efficacy. Conclusion: Rhizoma drynariae could improve endometrial receptivity of mouse models of dysfunctional embryo implantation as shown by increased numbers of pinopodes and higher levers of SCF, ERα, PR compared with the model group.

Tumor-infiltrating lymphocytes and levels of PD-L1 and BRCA protein expression may identify patients with breast cancer with a higher rate of BRCA1 mutations

Introduction. Breast cancer (BC) is a heterogeneous disease, treated as per the predictive role of immunohistoche­mistry (IHC) identifiers as estrogen/progesterone and HER2 receptor proteins. Deeper molecular classification (MC) identifies molecular subtypes according to the gene-expression profiles, with different molecular genetic alterations and biological features, present in the different subtype. An overlap between IHC and MC exists, even if somewhat incomplete. We aimed to identify the overlap between IHC and MC, and identify patients with basal-like subtype of BC. We hypothesized that the rates of tumor expression of breast cancer-related protein 1 (BRCA1), the type of tumor-infiltrating lymphocytes, and the expression of programmed death ligand 1 (PD-L1) by immune cells vary among different subtypes of BC. Material and methods. Parafin-embedded samples from 100 patients with primary invasive BC were analyzed and expression levels of estrogen and progesterone receptors, HER2 status, and Ki-67 were assessed via IHC, defining four groups – luminal A-like, luminal B-like (LumA, LumB), HER2-positive non-luminal, and triple negative (TN). The pri­mary endpoint of our study was to identify via IHC with CK5/6 and 17 basal-like subtypes of BC amongst others, and to describe specific clinicopathological features together with protein expression of BRCA1 and PD-L1 and tumor-infiltrating lymphocytes, using CD20, CD3, CD4, CD8, and FoxP3. Results. Basal-like BC were predominantly characterized as triple negative by IHC (p &lt; 0.05) and were more frequently seen among special BC subtypes as compared to no special type (NST), with p = 0.036. Their immune response was represented mostly by high concentration of intratumoral cytotoxic CD8 (+) T-lymphocytes (p &lt; 0.05) and stromal PD-L1-positive immune cells (p = 0.008). In these tumors, absence of expression of BRCA1 protein was more frequent (p &lt; 0.001). Basal-like subtype of BC with absent expression of BRCA1 is associated with poorer &lt;5-year survival (p = 0.001 and p = 0.017, respectively). Conclusions. The use of IHC can establish basal-like BC, the type of its immune response and possible dysfunction in the BRCA -gene, reflected in the lack of expression in the BRCA-related protein.

Clinical Features and Prognosis Analysis of Hormone Receptor-Positive, HER2-Negative Breast Cancer with Differential Expression Levels of Estrogen and Progesterone Receptors: A 10-Year Retrospective Study.

Estrogen and progesterone receptor status can predict breast cancer patient prognosis and treatment sensitivity, but research on low ER and PR levels and expression balance remains limited. From January 2010 to October 2016, 283 ER+/PR+/HER2-breast cancer patients who met the inclusion criteria were enrolled and divided into the H group (ER > 10%, N = 261) and the L group (1% ≤ ER ≤ 10%, N = 22). Groups were further divided into the HH group (ER > 10%/PR > 20%, N = 201), the HL group (ER > 10%/ER 1% ≤ PR ≤ 20% PR, N = 60), the LH group (1% ≤ ER ≤ 10%/PR > 20%, N = 5), and the LL group (1% ≤ ER ≤ 10%/1% ≤ PR ≤ 20%, N = 17). The LH group was excluded due to its small size, leaving the clinical and prognostic characteristics of 2 large groups and 3 subgroups to be analyzed. L group patients had significantly more stage N2 axillary lymph nodes than H group patients (31.8% vs. 9.2%, P = 0.007). Age (P = 0.011), menopause status (P = 0.001), and tumor size (P = 0.024) were significantly different in the HL vs. HH and LL groups. Five-year DFS (94.6% vs. 77.0%, P < 0.001) and 5-year OS (97.2% vs. 85.8%, P = 0.001) rates significantly differed between HH and HL. No significant differences in 5-year DFS (77.0% vs. 81.9%, P = 0.564) or 5-year OS (85.8% vs. 87.8%, P = 0.729) rates were observed between HL and LL; the OS rates of HL and LL were similar. In the group of ER+/PR+/HER2-patients, there was no significant prognostic difference between ER-low positive and ER-high positive groups, but low PR expression was significantly associated with a worse prognosis. The role of ER and PR balance in breast cancer progression and individualized treatment requires further investigation.

Significance of differential expression of OLFM4 in the development of endometrial adenocarcinoma.

The incidence of endometrial adenocarcinoma (EA) has increased worldwide in recent years due to the widespread use of estrogen therapy and the overall increase in life expectancy. However, we know of no sensitive molecular index that can be used to predict the onset of EA, evaluate the therapeutic effects of treatment agents, or provide prognostic benefit in post-treatment follow-up. To explore the correlation between human olfactomedin 4 (OLFM4) and the clinicopathologic parameters of EA, and to determine the precise involvement of OLFM4 as a related factor in the occurrence and development of EA. We enrolled 61 gynecologic patients for a retrospective study at the Tai'an Central Hospital of Shandong Province from January 1, 2016, to June 30, 2022. We determined the expression levels of estrogen receptor α (ERα), progesterone receptor (PR), and OLFM4 proteins in endometrial tissue with the immunohistochemical S-P staining method, and analyzed the correlations among ERα, PR, and OLFM4 protein expression levels and with the pathologic stage, histologic grade, myometrial invasiveness, and lymphatic metastasis of EA. The expression levels of OLFM4 in EA were higher than in normal endometrium (P = .036). The expression level of OLFM4 protein in stage II-III patients was higher than that in stage I patients (P = .034), and the expression levels of ERα and PR proteins in EA were lower than those in normal endometrial tissue (P = .014 and P = .0005). While we observed no correlation in endometrial tissues of disparate pathologic types between OLFM4 and the expression levels of ERα and PR proteins, we noted a positive correlation between the expression levels of ERα and PR protein. The expression level of OLFM4 protein increased with the malignant degree of endometrial lesions and OLFM4 protein expression was related to the FIGO stage of EA. And OLFM4 protein can be used as 1 of the potential diagnostic factors for endometrial lesions, which is worthy of further study.

WIN Symposium 2022 - Abstract Poster Presentations.

WIN Symposium 2022 - Abstract Poster Presentations.

Immunohistochemical features of expression of progesterone receptors of placental structures in premature birth

The objective: to study the immunohistochemical features of placenta in women with premature birth in 28–33 weeks of pregnancy. Materials and methods. 120 pregnant women (the main group) who were hospitalized and delivered in the Kyiv Perinatal Center during 2018–2020 at a gestation period of 23–33 weeks were examined. The women of the main group were divided into two subgroups depending on the term of birth – the 1st group included patients who delivered at 23–28 weeks of pregnancy, the patients of the 2nd group had labors at 29–33 weeks. Placentas of women in the main group were examined using morphological (histological method – staining with hematoxylin and eosin and van Gieson) and immunohistochemical methods (indirect streptavidin-peroxidase method for determining the expression level of progesterone receptors – PR). Results. Premature maturation of chorionic villi was found in 40 % of placentas of women in the 1st group 1, in 20 % – blood circulation disorders and the presence of acute inflammatory infiltration in the fetal membranes, decidual and chorionic membranes, 10 % – pathological immaturity of the placenta according to the variant of chaotic sclerosed villi. During the immunohistochemical study of RP, an unexpressed reaction was found in the epithelium and stromal cells of stem, intermediate and terminal villi – 1 point; in fetal membranes and extravillous cytotrophoblast – 2 points; in the endothelium of vessels – 0–1 point. In the placentas of women in the 2nd group premature maturation of villi was found in 70 % of cases, pseudoinfarcts of villi which are embedded in fibrinoid occupying a significant area – 45 %, afunctional zones – 55 %, blood circulation disorders – 35 %, pathological immaturity placenta according to the variant of chaotic, sclerosed villi – 20 %, acute inflammatory infiltration in the fetal membranes – 15 %. Immunohistochemical analysis of the placental barrier revealed the highest expression of RP in the nuclei of decidual cell which belong to the maternal structure. It should be noted the presence of expression of progesterone receptors in stem villi, fibroblasts and nuclei of the vessel wall. Minimal or absent expression was determined in the nuclei of other villous structures and their vessels. Conclusions. It was established that the receptivity of progesterone has its own characteristics in placental structures depending on the gestation period, which is an important factor in the choice of management for the prevention and reduction of perinatal losses for this contingent of pregnant women.

DYSREGULATED GATA2 AND GATA6 TRANSCRIPTION FACTOR EXPRESSION IN PATIENTS WITH ADENOMYOSIS: IMPLICATIONS FOR IMPAIRED ENDOMETRIAL RECEPTIVITY

GATA binding protein 2 and 6 (GATA2 and GATA6) are zinc-finger transcription factors involved in proliferation of hematopoietic and endocrine cell lineages, and in cell differentiation and organogenesis, respectively, which are important mechanisms in early pregnancy. Binding of GATA2 to the progesterone receptor (PGR) gene promoter induces PGR expression. GATA2 also interacts with PGR and contributes to PGR-mediated transcriptional activity. Gata2 deficient mice are infertile due to an impaired uterine response associated with lower PGR levels and attenuated progesterone signaling and defective decidualization.

Expression of Sex Hormone Receptors in Canine Osteosarcoma.

Simple SummaryOsteosarcoma is a bone tumor that arises from normal bone cells that become malignant. This is a disease that is relatively common in dogs and also affects humans. Dogs are a useful model for human osteosarcoma as they share many similarities including genetic changes, manner of spread and how they respond to treatment. In dogs, the tumors are frequently seen in large breeds and may be caused by environmental and genetic factors. Sex steroids have been shown to regulate bone metabolism directly and indirectly through receptors on bone. The aim of this study was to investigate the expression levels of sex hormone receptors in canine osteosarcoma tissue and cell lines. Our results demonstrate varying levels of receptors in tissue and a high expression of progesterone receptors in the canine osteosarcoma cell lines. Low oxygen levels further increased progesterone receptor expression. Lastly, estradiol decreased the expression of progesterone receptor in one of the cell lines, and progesterone decreased cell proliferation in the same cell line. Further investigation is recommended to determine whether or not sex steroid receptor levels and sensitivity to hormones are related.Sex steroids regulate bone metabolism directly and indirectly through receptors on bone. Estrogen receptors (ER-∝, ER-β), progesterone receptor (PR), and androgen receptor (AR), have been previously identified on human osteosarcoma (OSA) cells, and are considered to influence tumor growth, but their expression and role in canine OSA is unknown. The aim of this study was to characterize sex hormone receptor expression levels in naturally occurring OSA tissue and in three canine OSA cell lines. The expression of ER-α, ER-β, PR, and AR was investigated using RT-PCR. PR expression levels were also quantified in OSA cells cultured under hypoxic conditions or in the presence of estradiol. The effects of progesterone on cell proliferation were quantified. Results demonstrated varying expression levels of these receptors in five OSA subtypes. OSA cell lines demonstrated high gene expression levels of PR and low gene expression levels of ER-α and ER-β and no gene expression of AR. PR expression was increased in OSA cells cultured under hypoxic conditions in a HIF-∝ independent manner. Interestingly, one cell line expressed very high levels of PR, expression of which decreased in response to estradiol. In addition, progesterone decreased OSA cell proliferation in this particular cell line. Further investigation of the role of sex steroids, particularly PR and its ligands, in regulation of canine OSA is recommended.

Diagnostic diversity and heterogeneity of tumors: a real-world study of metastasis re-biopsy in advanced breast cancer.

Re-biopsy of metastasis in advanced breast cancer (ABC) has become an international convention to assist the diagnosis and evaluation of tumor heterogeneity. This study aimed to detect diagnostic diversity and inconsistencies among estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression levels between primary and metastatic lesions. We conducted a retrospective analysis of 1670 cases of ABC patients who had undergone at least one lesion re-biopsy from January 2010 to December 2018. The pathological diagnosis of biopsies, distribution of biopsy sites, and severe puncture complications at each site were collected. In addition, the inconsistency rates and related factors of ER, PR, and HER2 expression between primary and metastatic lesions were analyzed fully considering patients' demographic profiles and disease characteristics. In total, 1670 cases of breast cancer (BC) patients diagnosed by pathology underwent one to four biopsies of recurrences or metastases in different sites or at different stages during the rescue treatment, producing 2019 histopathological specimens which were analyzed in the study. Pathological diagnosis showed that eight patients had benign pathological diagnoses, 11 patients had second primary malignant tumors but without recurrences of breast cancer, and 17 patients had pathologically confirmed breast cancer recurrences combined with second primary cancer. In 1173 patients who presented ER, PR, and HER2 expressions in primary and metastatic lesions, the inconsistency rates of ER, PR, and HER2 were 17.5% (205/1173), 31.3% (367/1173), and 13.9% (163/1173), respectively. The multivariate analysis showed that the age at the onset of breast cancer or adjuvant endocrine therapy was an independent factor affecting changes in PR expression level. Except one liver puncture with local hemorrhage and two lung punctures with hemopneumothorax, no other severe puncture complications occurred in 1950 non-surgical rebiopsies. The pathological diagnosis of metastasis re-biopsy of ABC was diverse, and the ER, PR, and HER2 expression levels were inconsistent between primary and metastatic lesions. Therefore, more attention should be paid to perform biopsies of relapsed and metastatic breast cancers routinely in clinical practice.

High Levels of Progesterone Receptor B in MCF-7 Cells Enable Radical Anti-Tumoral and Anti-Estrogenic Effect of Progestin.

The widely reported conflicting effects of progestin on breast cancer suggest that the progesterone receptor (PR) has dual functions depending on the cellular context. Cell models that enable PR to fully express anti-tumoral properties are valuable for the understanding of molecular determinant(s) of the anti-tumoral property. This study evaluated whether the expression of high levels of PR in MCF-7 cells enabled a strong anti-tumoral response to progestin. MCF-7 cells were engineered to overexpress PRB by stable transfection. A single dose of Promegestone (R5020) induced an irreversible cell growth arrest and senescence-associated secretory phenotype in MCF-7 cells with PRB overexpression (MCF-7PRB cells) but had no effect on MCF-7 cells with PRA overexpression. The growth-arresting effect was associated with downregulations of cyclin A2 and B1, CDK2, and CDK4 despite an initial upregulation of cyclin A2 and B1. R5020 also induced an evident activation of Nuclear Factor κB (NF-κB) and upregulation of interleukins IL-1α, IL-1β, and IL-8. Although R5020 caused a significant increase of CD24+CD44+ cell population, R5020-treated MCF-7PRB cells were unable to form tumorspheres and underwent massive apoptosis, which is paradoxically associated with marked downregulations of the pro-apoptotic proteins BID, BAX, PARP, and Caspases 7 and 8, as well as diminution of anti-apoptotic protein BCL-2. Importantly, R5020-activated PRB abolished the effect of estrogen. This intense anti-estrogenic effect was mediated by marked downregulation of ERα and pioneer factor FOXA1, leading to diminished chromatin-associated ERα and FOXA1 and estrogen-induced target gene expression. In conclusion, high levels of agonist-activated PRB in breast cancer cells can be strongly anti-tumoral and anti-estrogenic despite the initial unproductive cell cycle acceleration. Repression of ERα and FOXA1 expression is a major mechanism for the strong anti-estrogenic effect.

«Salivaomics» of Different Molecular Biological Subtypes of Breast Cancer

The aim of the study was to determine the metabolic characteristics of saliva depending on the molecular biological subtype of breast cancer, as well as depending on the expression levels of HER2, estrogen receptors (ER), and progesterone receptors (PR). The study included 487 patients with morphologically verified breast cancer and 298 volunteers without breast pathologies. Saliva samples were obtained from all patients strictly before the start of treatment and the values of 42 biochemical indicators were determined. It has been established that the saliva of healthy volunteers and patients with various molecular biological subtypes of breast cancer differs in 12 biochemical indicators: concentrations of protein, urea, nitric oxide, malondialdehyde, total amino acid content, and activity of lactate dehydrogenase, alkaline phosphatase, gamma-glutamyltransferase, catalase, amylase, superoxide dismutase, and peroxidases. The saliva composition of patients with basal-like breast cancer differs from other subtypes in terms of the maximum number of indicators. Changes in biochemical indicators indicated an increase in the processes of lipid peroxidation and endogenous intoxication and a weakening of antioxidant protection, which correlates with the severity of the disease and the least favorable prognosis for this subtype of breast cancer. An analysis was made of the individual contribution of the expression level of HER2, estrogen, and progesterone receptors to changes in the biochemical composition of saliva. The HER2 (−)/HER2 (+) group, which should be considered as a single group, as well as ER-positive breast cancer, differ statistically significantly from the control group. For ER/PR-positive breast cancer, a more favorable ratio of saliva biochemical indicators was also noted compared to ER/PR-negative breast cancer.

Medicinal Mushroom Leucocalocybe mongolica Imai Extracts Improve Mammary Gland Differentiation in Lactating Rats via Regulating Protein Expression.

Leucocalocybe mongolica is a known medicinal mushroom in China. It possesses many biological activities. This study investigated the effect of L. mongolica petroleum ether and water extracts (200, 500, and 1,000 mg/kg BW) on mammary gland differentiation during lactation. However, prolactin, growth hormone, progesterone, and estrogen levels were determined in serum by ELISA assay. Immunofluorescence, western blot, and real-time PCR were utilized to evaluate the expression levels of β-casein, α-Lactalbumin, prolactin receptor, progesterone receptor, and STAT-5a. The immunohistochemistry staining was used to detect the presence of steroid receptors. The results showed that petroleum ether and water extracts increased milk yield and milk content of calcium, total fat, total carbohydrate, and total protein. Prolactin and growth hormone levels were significantly upregulated in all treated groups compared with the control group. In contrast, progesterone and estrogen were downregulated. The high doses of petroleum ether and water extracts increased the expression levels of β-Cas, α-Lactalb, PRLR, PR, and STAT-5a. The observation of histological sections showed that the extracts induced higher mammary gland differentiation than the control group. This study is the first to use mushrooms as nutritional supplements to improve milk production and mammary gland differentiation during lactation.

Abstract 3115: Establishment and characterization of patient-derived breast cancer models for cancer studies

Abstract BACKGROUND: Despite the progress and development of targeted agents and Immunotherapeutics, breast cancer is still the leading cause of death among women worldwide. At present, targeted therapy for breast cancers include endocrine blockage therapy for estrogen receptor positive (ER+) tumors and trastuzumab or lapatinib for HER2 positive (HER2+) tumors and CDK inhibitors for HER negative (HER-) tumors as well as PARP inhibitors for BRCA1/2 mutations. There is still a high unmet need for triple negative breast cancer (TNBC) and relapsed breast cancers with specific mutations. Breast cancer is a highly heterogeneous disease and reliable breast cancer models are needed to develop new clinical therapies and better reflect tumor biology. Patient-derived xenograft (PDX) models have been widely used for understanding tumor characteristics and represent human heterogeneity more faithfully and thus are suitable for mouse clinical studies for predicting drug efficacy in the clinic. Here we report the establishment and characterization of a panel of breast cancer (BC) PDX for preclinical research. METHODS: Tumor samples from patients’ breast tumor or metastastic lesion obtained via surgery, biopsy, or pleural effusions/ascites were engrafted subcutaneously in immunodeficient mice to establish PDX models. The models were classified and characterized by histopathology, immunohistochemistry (IHC), and breast cancer specific biomarkers such as estrogen receptor (ER), progesterone receptor (PR) and HER2. Genomic analysis of these models was performed by next generation sequencing (NGS). In these breast cancer models, the effects of estrogen on tumor growth and targeted endocrine therapy such as Fulvestrant were evaluated. The change of tumor volume over time was used to determine the growth rate and response to treatment in mice. RESULTS: A series of BC PDX models derived from primary patient breast tumor or metastatic lesions were successfully established and characterized. Key characteristics of parental tumors, such as histopathology, clinical markers, gene expression and copy number, as well as estrogen dependence was retained. The IHC data indicated various expression levels of ER, PR and HER2 across the panel, with TNBC being the dominant subtype. ESR1 mutation, which may play an important role in BC progression and endocrine therapy resistance, was also identified in an estrogen-independent model. In vivo, these models showed distinct tumor growth rates and different pharmacodynamic responses to standard of care agents. For example, ESR1 mutant model was responsive to Fulvestrant. CONCLUSIONS: The established BC PDX panel represent a range or ER/PR/HER2 expression status from primary and advanced cancer providing a series of preclinical models for breast cancer research and potential for mouse clinical trial enrollment. Citation Format: Leilei Chen, Xueying Yang, Likun Zhang, Xiaobo Chen, Henry Q.X. Li, Jingjing Wang. Establishment and characterization of patient-derived breast cancer models for cancer studies [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 3115.

Abstract CT517: Amcenestrant, an oral selective estrogen receptor (ER) degrader (SERD), in ER+/HER2- advanced breast cancer (aBC): combined biomarker analyses from a Phase 1/2 study in postmenopausal women and a Phase 1 study in postmenopausal Japanese women

Abstract Background: Amcenestrant is an optimized oral SERD that has shown safety and clinical benefit in patients (pts) with wild-type (WT) and mutated ESR1 aBC. Here we provide a pooled analysis of biomarkers from two studies in heavily-pretreated, postmenopausal women with ER+/HER2- aBC. Methods: Pooled analysis included study data from AMEERA-1 (NCT03284957), in which pts received single-agent amcenestrant in dose escalation (20-600 mg QD or 300 mg BID) and dose expansion (400 mg QD), and from AMEERA-2 (NCT03816839), in which Japanese pts received single-agent amcenestrant at 400 mg QD or 300 mg BID. Mutational profiling of plasma circulating cell-free DNA was conducted by droplet digital polymerase chain reaction (ddPCR) for 12 pathogenic ESR1 mutations at baseline (BL) and on treatment (OT; Cycle 2, Day 28), and by next-generation sequencing (NGS; 77-gene panel) at BL and end of treatment (EOT). Clinical benefit (CB; complete response + partial response [PR] + stable disease ≥ 24 weeks) was assessed in pooled pts who received amcenestrant≥ 150 mg QD or BID. In tumor tissue, ER, progesterone receptor (PgR), Ki67 and Bcl-2 expression levels over time were assessed by immunohistochemistry; functional ER pathway activity was assessed by gene set variation analysis with RNA-seq data (ER activity score). Results: Among pts with data for ESR1 mutation status at BL (N = 80; ddPCR), 41 pts were WT and 39 pts had at least one ESR1 mutation, with D538G and Y537S the most prevalent. CB was observed in pts with both WT (13 pts) and mutated ESR1 (12 pts) at BL. The most frequent pathogenic mutations detected in pts (N = 79; NGS) at BL were ESR1 (49%), followed by PI3KCA (46%)and TP53 (33%). In response-evaluable pts with ESR1 mutational profiling at BL and OT (N = 40; ddPCR), 17 of 19 pts with ESR1 mutation at BL showed a decrease in ESR1 mutation allele frequency, independently of clinical benefit. Eight pts showed an increase (7/25 no CB and 1/15 CB). Among 17 pts with biopsies, pts with ER or PgR -/low (H-score: 0-3) at BL did not derive benefit from treatment. In the remaining patients with ER high (H-score ≥ 140), no difference between pts with and without CB was observed in ER, Bcl-2 or ER activity score, while pts with CB had a tendency for lower Ki67. ER and PgR decreased upon treatment independently of CB, while ER activity score and Ki67 mostly decreased in pts with CB and mostly increased in pts without CB. Conclusions: In postmenopausal women with ER+/HER2- aBC treated with single-agent amcenestrant, low Ki67 at BL and the pharmacodynamic decrease of Ki67 and ER activation score by amcenestrant trended toward an association with CB, whereas increase in ESR1 mutation allele frequency on treatment trended toward an association with lack of CB. Clinical benefit was observed in both pts with WT and mutated ESR1 at BL. Citation Format: Hiroji Iwata, Aditya Bardia, Simon Lord, Hannah M. Linden, Mario Campone, Kenji Tamura, Kan Yonemori, Toru Mukohara, Cécile Combeau, Nils Ternes, Dimitri Carene, Jeff Ming, Joon Sang Lee, Marina Celanovic, Anne-Laure Bauchet, Monsif Bouaboula, Tomoyuki Tanaka, Yumiko Kawabata, Sarat Chandarlapaty. Amcenestrant, an oral selective estrogen receptor (ER) degrader (SERD), in ER+/HER2- advanced breast cancer (aBC): combined biomarker analyses from a Phase 1/2 study in postmenopausal women and a Phase 1 study in postmenopausal Japanese women [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 CT517.

Discordance of HER2 Positive Classic Invasive Lobular Carcinoma Between IHC/FISH and Oncotype DX: A Case Report and Literature Review

The classical-type of invasive lobular carcinoma (ILC) usually expresses high levels of estrogen receptor (ER) and progesterone receptor (PR) and does not over-express human epidermal growth factor receptor 2 (HER2) and has a low level of expression of the proliferative marker. Their prognosis is comparable with those of histologic grade 1-2 invasive ductal carcinoma (IDC). HER2 status is prognostically significant and has a huge impact on clinical management; thus, its correct testing and evaluation are critical. Discordant results for HER2 between immunohistochemistry (IHC)/fluorescence in situ hybridization (FISH) and Oncotype DX (ODX) testing can be occasionally seen and cause confusion among clinicians. Here, we present a case of classical ILC (cILC), which was HER2 positive by IHC/FISH but negative by ODX. We also review relevant literature and provide a possible explanation for this discordancy and suggestions on how to approach the discordant results and guide the clinical management.

Immunomorphological signs of chronic endometritis in patients after failed attempts of auxiliary reproductive technologies

The objective: to analyze the morphological and immunohistochemical features of the endometrium in the patients with chronic endometritis after unsuccessful attempts of assisted reproductive technologies (ART). Materials and methods. A prospective study was conducted in women with a history of chronic endometritis on the basis of the Medical Center LLC “ISIDA-IVF” for the period from 2019 to 2021. The I group included 55 women of reproductive age with chronic endometritis and repeated unsuccessful attempts of ART, the control group (CG) – 40 women of reproductive age without fertility disorders who are preparing for the replacement motherhood programs or who are oocyte donors. The results of the endometrial biopsy performed on the 5–7th and 19th–21st days of the menstrual cycle using a pipelle aspiration curette were studied for the assessment of the immunomorphological characteristics of the endometrium in the patients with chronic endometritis. The immunoperoxidase method with primary specific monoclonal antibodies was used for the immunomorphological study of estrogen and progesterone receptors. Differences at p&lt;0.05 were considered statistically significant. Results. Pathomorphological study of the endometrium revealed characteristic signs of chronic inflammation – the presence of a large number of plasma cells in the endometrium stroma, lymphoid infiltrates near the blood vessels and the gland orifices, unevenly expressed stroma fibrosis, sclerotic changes in the walls of spiral arteries. All examined persons had two or more morphological signs of chronic endometritis (CE). An increase number of macrophages and monocytes in the endometrium glands and stroma was found by CE – 31.3±2.9 % versus 2.3±0.1 % in CG (р&lt;0.05). An increase proliferative activity of epithelium cells of the endometrium glands and stroma on the 5-7th day of the menstrual cycle in patients in the I group compared to similar indicators of the secretion phase in CG was determined. The proliferation of glandular and stromal cells, detected on the 19th–21st days of the menstrual cycle, had the intensification of the programmed cell death process in the covering and glandular epithelium of the endometrium. This was characterized by the structural changes in the cell nuclei – the marginal state of chromatin, the appearance of karyorrhexis and karyopyknosis. In the endometrium stroma the presence of capillary-type vessels was found, the intensity of their development had a strong correlation with the degree of severity of the inflammatory changes (r=0.74; p&lt;0.05). During the study of progesterone receptors mainly a decrease of the level of expression in the glands both compared to the indicators of healthy women and in the secretion phase compared to the proliferation phase - H-score 145.5±7.7 was found, in the proliferation phase versus H-score 55.5±10.4 in the secretion phase (р&lt;0.05). Conclusions. Immunomorphological study of the endometrium in patients with chronic endometritis after unsuccessful attempts of assisted reproductive technologies demonstrates that the inflammatory changes in the tissues have clear morphological criteria, which are most pronounced on the 5-7th day of the menstrual cycle – the presence of plasma cells, stroma fibrosis, sclerosis vessel walls, decrease of the estrogen and progesterone level receptors. These morphological and immunohistochemical changes persist in the secretory phase of the menstrual cycle with the most significant manifestations in the form of a decrease in the level of progesterone receptors.

Characterization of Weakly Hormone Receptor (HR)-Positive, HER2-Negative Breast Cancer and Current Treatment Strategies

BackgroundHormone receptor (HR) and human epidermal growth factor receptor-2 (HER2) status is critical for determining management of breast cancer. Previous reports of small cohorts with weak HR-positive (HR+)/HER2-negative (HER2-) disease showed similar rates of pathologic complete response (pCR) following neoadjuvant chemotherapy (NAC) as triple negative breast cancer (TNBC). This study aims to further characterize this group, focusing on pCR rates following NAC. Patients and MethodsPatients with stage I-III, HR+/HER2- breast cancer were identified using the University of Wisconsin Hospital Cancer Registry. Medical records were reviewed for demographics, tumor characteristics with quantification level of estrogen and progesterone receptor (≤33%), treatment, and follow-up data. ResultsData was reviewed from 2,900 patients and a total of 64 patients met inclusion criteria. Eighty percent received chemotherapy, about half with NAC (n = 30, 48%). Of 28 patients who received NAC followed by breast and axillary surgery, 12 (43%; 95% CI 25%-63%) had pCR (ypT0/Tis/ypN0). Of the 11 patients who had biopsyproven nodal disease at diagnosis and NAC followed by axillary surgery, 7 (64%, 95% CI 31%-89%) patients had pCR at the axilla. Only one patient with pCR developed recurrent disease. For those that recurred, median time to recurrence was 13.6 (5.6-48.7) months. ConclusionsBreast cancers that are HER2- and weakly HR+ treated with NAC demonstrated pCR rate more similar to TNBC than breast cancers that are strong HR+. Neoadjuvant approaches may improve pCR rates, which provides important prognostic information. Clinical trials should be developed to focus on this unique patient cohort.

55P Morphological changes and regulation of hormone receptor-related proteins in breast cancer patients with higher levels of progesterone receptor A than B treated with mifepristone

Twenty breast cancer patients from Magdalena V. de Martínez Hospital, Buenos Aires, selected by their higher levels of progesterone receptor isoform A (PRA) than isoform B (PRB) were treated for 14 days with 200 mg mifepristone (MFP) p.o. before surgery (MIPRA; NCT02651844). A decrease in the proliferation index, greater than 30% was observed in 70% of the MFP-treated patients [primary endpoint (e.p.)]. RNA-Seq studies performed in 8 paired samples supported these findings and suggested that MFP increased tissue remodeling and immune-related pathways (secondary e.p.).

101P Proteome and RNA-Seq changes in breast cancer patients with higher levels of progesterone receptor A than B after mifepristone treatment

Antiprogestins inhibit experimental breast cancer growth when progesterone receptor isoform A (PRA) levels are higher than those of isoform B (PRB). Thus, we conducted a window of opportunity trial to determine the therapeutic effects of oral mifepristone (MFP, 200mg) in 20 breast cancer patients selected by their high PRA/PRB isoform ratio (MIPRA; NCT02651844). We identified 14/20 patients that achieved the pre-specified response parameter (30% relative reduction) showing a 49.62% decrease in Ki67 staining after MFP treatment (p = 0.0003).