Distinct Breast Cancer Subtypes Research Articles

Abstract PO4-02-12: MDA iLobular Prognostic Tool: A Novel Approach for Risk Stratification in Invasive Lobular Carcinoma

Abstract Background: Invasive lobular carcinoma (ILC) is a distinct subtype of breast cancer that differs from the more common invasive ductal carcinoma (IDC) by its unique characteristics that influence prognosis. Recent studies have shown that ILC is associated with worse long-term outcomes compared to IDC. Risk stratification is essential in breast cancer for tailoring treatment plans to the individual patient’s needs, maximizing the chances of successful outcomes and minimizing unnecessary interventions. Although there are multiple tools available for breast cancer, there is currently not a risk stratification tool that is specific for ILC. The MDA iLobular prognostic tool is the first risk stratification tool that has been developed specifically for ILC patients. Methods: We retrospectively searched for patients treated at MD Anderson Cancer Center with a diagnosis of stage I-III ILC in our prospectively collected electronic database. The study focused on two primary endpoints: Overall Survival (OS) and Distant Recurrence Free Survival (DRFS). We utilized univariate and multivariate Cox Proportional Hazard (PH) regression models to assess the statistical significance of all variables. The univariate Cox analysis identified prognostic factors, which were further analyzed using backward and stepwise multivariate Cox proportional hazards regression analysis. This process helped identify statistically significant prognostic factors that were included in the final multivariate models. We estimated hazard ratios and 95% confidence intervals for each factor, considering a P-value of < 0.05 as statistically significant. To evaluate the performance of the fitted multivariate Cox PH regression models for OS and DRFS, we randomly divided two-thirds of the data points into a training dataset, while the remaining one-third constituted the test dataset. We assessed the discrimination capacity of each model using Harrell's C-index. Results: The study included a total of 4,216 female patients, with a median age of 56 years. The median pathological tumor size was 2 mm, and the median number of lymph nodes was one. Among these patients, 1,376 were pre-menopausal, while 2,837 were post-menopausal. The training cohort was a subset of 2,950 patients and the test cohort was a subset of 1,266 patients. After evaluating various prognostic models, we identified the model with the highest prognostic accuracy for OS and DRFS. This selected model demonstrated a Harrell's C-index of 0.704 for OS and 0.718 for DRFS on the training dataset and a Harrell's C-index of 0.702 for OS and 0.671 for DRFS on the test dataset. The model incorporated several covariates, including age at the time of diagnosis, number of lymph nodes, pathological tumor size (mm), ER status, tumor grade, ILC histology, and the presence or absence of concomitant LCIS (Table 1). Conclusion: In conclusion, the MDA iLobular prognostic tool represents a significant advancement as the first dedicated tool for risk stratifying ILC, providing valuable guidance for tailoring therapy to individual ILC patients based on their specific risk profiles. Table 1. Multivariate Cox proportional hazard model parameter estimates for OS and DRFS Citation Format: Jason Mouabbi, Sarah Pasyar, Roland Bassett, Akshara Singareeka Raghavendra, Amy Hassan, Rachel Layman, Debu Tripathy. MDA iLobular Prognostic Tool: A Novel Approach for Risk Stratification in Invasive Lobular Carcinoma [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-02-12.

Abstract PO1-27-07: Is HER2-low a biologically distinct breast cancer (BC) subtype? Prognosis and pathological complete response rate after neoadjuvant treatment (NAT) in early breast cancer (BC) HER2 negative

Abstract Background: Overexpression of HER2 is a significant prognostic and predictive factor in early breast cancer. HER2 positive tumors are those scored by immunohistochemistry (IHC) 3+ or 2+ with amplification by in situ hybridization (ISH). These tumors may benefit from HER2-targeted treatment and additionally, in early HER2-positive BC, achieving a complete pathological response after neoadjuvant treatment improves patient survival. In recent years, new anti-HER2 antibody-drug conjugates have proven effective for HER2 low BC (defined as IHC score 1+ or 2+ not amplified) in the metastatic disease setting; however, in HER2-low early BC, studies testing novel anti-HER2 antibody-drug conjugates as neoadjuvant therapy (NAT) are ongoing. Currently, we don´t know exactly whether HER2 expression can influence the pathological response rate after NAT or disease-free survival (DFS) in these patients compared to HER2-zero (IHC 0). The aim of our study is to determine the impact on response rate to NAT and survival outcomes in early HER2-negative BC. Methods: We conducted a retrospective study in two hospitals in Andalucia, Spain. Patients with early HER2 negative BC treated with NAT from January 2015 to June 2022 were included. Patients were divided into HER2 low patients (IHC 1+ or 2+ not amplified) and HER2 0 (IHC 0). We collected clinical and pathological characteristics, pathological response rate using the Residual Cancer Burden (RCB) system where a complete pathological response (pCR) was defined as ypT0/ypTis and ypN0, and survival outcomes. The primary objective of the study was to analyze the pCR rate after NAT according to HER2 score, and secondary objectives were to assess disease-free survival and overall survival (DFS and OS rates). Results: 574 patients were included (100% women). 397 patients had hormone receptors (luminal BC) on these tumors, and 177 did not have them, i.e., triple-negative BC (TNBC). 225 patients were HER2-zero, and 312 patients were HER2-low (253/312 patients had luminal BC and 59/312 patients were TNBC). The pCR in HER2-low patients was 17.3% and 23.1% in HER2-zero patients (p=0.047). For luminal BC patients, the pCR was 16.7% in HER2-low tumors and 13.7% in HER2-zero tumors (p=0.29). Similarly, there was no difference in pCR rates in TNBC patients (45.8% in HER2-low and 53.8% in HER2-zero tumors, respectively, (p=0.958). The overall survival (OS) at 96 months was 88.7% (95% CI 85.6%-92%). Regarding survival outcomes, neither HER2 expression level was associated with higher 8-year DFS: 81.1% in HER2-low patients (95% CI 75.7%-86.8%) and 74.9% in HER2-zero patients (95% CI 62.3%-90.1%) p=0.64. There was no difference between histological subtypes at 8-years regarding DFS rate: 80.5% (95% CI 74.3%-87.2%) in luminal HER2-low patients and 76.3% (95% CI 60.8%-95.7%) in luminal HER2-zero patients, p=0.22; 83.8% in TNBC HER2-low (95% CI 74.5%-94.2%) and 77.5% in TNBC HER2-zero patients (95% CI 69.4%-86.6%) p=0.26. We also didn´t find significant differences in terms of OS. For HER2-low patients, the 8-year OS was 90.9% (95% CI 87%-94.9%) and for HER2-zero patients, it was 86.4% (95% CI 80.8%- 92.5%) p=0.46. There were also no differences in OS for different histological subgroups with an 8-year OS in luminal HER2-low breast cancer patients of 92.5% (95% CI 88%-96.7%) and 87% in HER2-zero (95% CI 78.9%-96.1%) p=0.91. In patients with triple-negative breast cancer phenotype, the OS was 84.2% for HER2-low (95% CI 74.5%-95.2%) and 85.3% for HER2-zero (95% CI 77.9%-93.4%) p=1. Conclusions: We found no difference in survival outcomes and response rate to conventional NAT between HER2-low and HER2-zero expression levels. Therefore, our data do not support the hypothesis of HER2-low as a biologically specific breast cancer subtype. Further research on this approach with HER2 antibody-drug conjugate schemes as an alternative to traditional NAT schemes is warranted. Citation Format: Ana Gil-Torralvo, Yeray Rodriguez, Alejandro Falcon, David Morales, Mónica Cejuela, Isabel Miras, Marta Amérigo, Manuel Ruíz - Borrego, Juan Bayo, Francisco Javier Salvador Bofill. Is HER2-low a biologically distinct breast cancer (BC) subtype? Prognosis and pathological complete response rate after neoadjuvant treatment (NAT) in early breast cancer (BC) HER2 negative [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-27-07.

Abstract PO4-02-09: Clinical outcomes of neoadjuvant chemotherapy in HER2-low early breast cancer

Abstract BACKGROUND: According to immunohistochemistry (IHC) expression of HER2 receptor, breast cancer (BC) can be classified as either IHC score 0, 1+, 2+ or 3+. Until recently, two distinct BC subtypes were recognized depending on the HER2 IHC expression and in situ hybridization (ISH) score: HER2 positive (IHC 3+ or IHC 2+ ISH-amplified) and HER2 negative (IHC 0, 1+ or 2+ ISH negative). More recently a new BC entity termed HER2-low was acknowledged, defined as either HER2 IHC 1+ or 2+ ISH-negative. Given that no treatment benefit was observed in HER2-low group of patients in the pivotal trastuzumab studies, many years had to pass before the discovery of antibody-drug conjugates such as trastuzumab deruxtecan, that led to a significant improvement in the clinical outcome of HER2-low BC, compared to standard therapy options. It is still debated whether HER2-low BC represents a distinct biological subtype. The aim of this study was to determine whether there is an impact of HER2-low status on the effect of neoadjuvant chemotherapy (NACT) and its primary indicator - the rate of the pathologic complete response (pCR). METHODS: A retrospective study of 363 BC cases who received NACT between January 2020 and December 2022 at University Hospital Centre Zagreb, Croatia, was conducted with prior Ethics Committee approval. Histopathological characteristics of tumours available from the hospital information system (BIS), including hormone receptor status (ER, PR), HER2 status and Ki-67 at the time of diagnosis and after neoadjuvant treatment, as well as pCR rates, were analysed. pCR rates were calculated for HER2-low and HER2 0 cases. Chi square test was used to analyse association between pCR rate and HER2 status. RESULTS: After exclusion of HER2 positive BC cases, as well as cases with missing data, a total of 215 patients were included in the analysis. Of those, 101 (47%) were HER2-low, and 114 (53%) were HER2 negative. The majority of patients (N=151, 70.2%) had luminal BC, while 64 (29.8%) patients had triple negative BC (TNBC). In the luminal group, 86 cases (57%) were HER2-low, and 65 (43%) were HER2 0. In the TNBC group, 15 cases (23.4%) were HER2-low and 49 (76.6%) were HER2 0. The rate of pCR among luminal subtypes was 6.2% for HER2-low tumours, and 15.4% for HER2 0 tumours (p=.051559), approaching statistical significance. In the TNBC group, the pCR rate for HER2-low group was 60%, compared to 40% in the HER2 0 group, trending towards, but not reaching statistical significance (p=.191564). CONCLUSION: A trend toward higher pCR rates after neoadjuvant chemotherapy was observed in the luminal HER2 0 group compared to HER2-low luminal BC, almost reaching statistical significance. Interestingly, in TNBC there was a trend towards higher pCR rates among the HER2-low group, although a small number of patients precludes any definitive conclusions. Further trials that include novel targeted therapies are needed, as that might lead to significant changes in therapeutic approach, as well as clinical outcome of HER2-low BC patients. Citation Format: Dora Gudelj, Katarina Čular, Lea Toula, Marija Križić, Marina Popović, Natalija Dedić Plavetić, Ana Kelečić, Gordana Ivanac, Majana Soče, Iva Kukal Gjergjaj, Tajana Silovski. Clinical outcomes of neoadjuvant chemotherapy in HER2-low early breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-02-09.

A gap analysis of UK biobank publications reveals SNPs associated with intrinsic subtypes of breast cancer

Breast cancer is a multifaceted disease and a leading cause of cancer morbidity and mortality in females across the globe. In 2020 alone, 2.3 million women were diagnosed and 685,000 died of breast cancer worldwide. With the number of diagnoses projected to increase to 3 million per year by 2040 it is essential that new methods of detection and disease stratification are sought to decrease this global cancer burden.Although significant improvements have been made in breast cancer diagnosis and treatment, the prognosis of breast cancer remains poor in some patient groups (i.e. triple negative breast cancer), necessitating research into better patient stratification, diagnosis and drug discovery. The UK Biobank, a comprehensive biomedical and epidemiological database with a wide variety of multiomics data (genomics, proteomics, metabolomics) offers huge potential to uncover groundbreaking discoveries in breast cancer research leading to improved patient stratification. Combining genomic, proteomic, and metabolic profiles of breast cancer in combination with histological classification, can aid treatment decisions through accurate diagnosis and prognosis prediction of tumor behaviour.Here, we systematically reviewed PubMed publications reporting the analysis of UK Biobank data in breast cancer research. Our analysis of UK Biobank studies in the past five years identified 125 publications, of which 76 focussed on genomic data analysis. Interestingly, only two studies reported the analysis of metabolomics and proteomics data, with none performing multiomics analysis of breast cancer. A meta-analysis of the 76 publications identified 2870 genetic variants associated with breast cancer across 445 genes. Subtype analysis revealed differential genetic alteration in 13 of the 445 genes and the identification of 59 well-established breast cancer genes. in differential pathways. Pathway interaction analyses illuminated their involvement in general cancer biomolecular pathways (e.g. DNA damage repair, Gene expression). While our meta-analysis only measured genetic differences in breast cancer due to current usage of UK Biobank data, minimal multi-omics analyses have been performed and the potential for harnessing multi-omics strategies within the UK Biobank cohort holds promise for unravelling the biological signatures of distinct breast cancer subtypes further in the future.

Rapid autopsies to enhance metastatic research: the UPTIDER post-mortem tissue donation program

Research on metastatic cancer has been hampered by limited sample availability. Here we present the breast cancer post-mortem tissue donation program UPTIDER and show how it enabled sampling of a median of 31 (range: 5-90) metastases and 5-8 liquids per patient from its first 20 patients. In a dedicated experiment, we show the mild impact of increasing time after death on RNA quality, transcriptional profiles and immunohistochemical staining in tumor tissue samples. We show that this impact can be counteracted by organ cooling. We successfully generated ex vivo models from tissue and liquid biopsies from distinct histological subtypes of breast cancer. We anticipate these and future findings of UPTIDER to elucidate mechanisms of disease progression and treatment resistance and to provide tools for the exploration of precision medicine strategies in the metastatic setting.

Clustering of HR + /HER2− breast cancer in an Asian cohort is driven by immune phenotypes

Breast cancer exhibits significant heterogeneity, manifesting in various subtypes that are critical in guiding treatment decisions. This study aimed to investigate the existence of distinct subtypes of breast cancer within the Asian population, by analysing the transcriptomic profiles of 934 breast cancer patients from a Malaysian cohort. Our findings reveal that the HR + /HER2− breast cancer samples display a distinct clustering pattern based on immune phenotypes, rather than conforming to the conventional luminal A-luminal B paradigm previously reported in breast cancers from women of European descent. This suggests that the activation of the immune system may play a more important role in Asian HR + /HER2− breast cancer than has been previously recognized. Analysis of somatic mutations by whole exome sequencing showed that counter-intuitively, the cluster of HR + /HER2− samples exhibiting higher immune scores was associated with lower tumour mutational burden, lower homologous recombination deficiency scores, and fewer copy number aberrations, implicating the involvement of non-canonical tumour immune pathways. Further investigations are warranted to determine the underlying mechanisms of these pathways, with the potential to develop innovative immunotherapeutic approaches tailored to this specific patient population.

Pathway-based signatures predict patient outcome, chemotherapy benefit and synthetic lethal dependencies in invasive lobular breast cancer.

Invasive Lobular Carcinoma (ILC) is a morphologically distinct breast cancer subtype that represents up to 15% of all breast cancers. Compared to Invasive Breast Carcinoma of No Special Type (IBC-NST), ILCs exhibit poorer long-term outcome and a unique pattern of metastasis. Despite these differences, the systematic discovery of robust prognostic biomarkers and therapeutically actionable molecular pathways in ILC remains limited. Pathway-centric multivariable models using statistical machine learning were developed and tested in seven retrospective clinico-genomic cohorts (n = 996). Further external validation was performed using a new RNA-Seq clinical cohort of aggressive ILCs (n = 48). mRNA dysregulation scores of 25 pathways were strongly prognostic in ILC (FDR-adjusted P < 0.05). Of these, three pathways including Cell-cell communication, Innate immune system and Smooth muscle contraction were also independent predictors of chemotherapy response. To aggregate these findings, a multivariable machine learning predictor called PSILC was developed and successfully validated for predicting overall and metastasis-free survival in ILC. Integration of PSILC with CRISPR-Cas9 screening data from breast cancer cell lines revealed 16 candidate therapeutic targets that were synthetic lethal with high-risk ILCs. This study provides interpretable prognostic and predictive biomarkers of ILC which could serve as the starting points for targeted drug discovery for this disease.

Abstract 573: SLC22A17 as a promising target for triple-negative breast cancer

Abstract Introduction: Triple-negative breast cancer (TNBC) represents a highly aggressive subtype of breast cancer, accounting for approximately 15% of all cases of invasive breast cancer globally. The absence of a well-defined cell membrane receptor has significantly limited the therapeutic options available for treating this malignancy. Consequently, there is a compelling need to explore novel receptors that could potentially revolutionize the treatment strategies employed for TNBC. Recent scientific research has unveiled SLC22A17, a cell surface receptor known for its involvement in iron transport, as a substantial contributor to the development of various cancer types. Thus, the primary objective of this study is to comprehensively evaluate the significance of SLC22A17 and its potential as a therapeutic target in TNBC. Experimental Procedures: In this study, we meticulously examined the expression patterns of SLC22A17 across distinct subtypes of breast cancer utilizing immunohistochemistry. Computational tools were employed to delve into the role of SLC22A17 within TNBC datasets. To assess the impact of SLC22A17 on TNBC, we employed various methods, including siRNA-mediated silencing, to investigate its role in cell proliferation, apoptosis, epithelial-mesenchymal transition (EMT), and migration. Additionally, we conducted western blot analyses to assess the expression levels of SLC22A17 and cellular signaling molecules, such as Akt/mTOR and JAK/STAT, within the context of TNBC cells. Results: Our analysis revealed a significant upregulation of SLC22A17 in both TNBC tissues and cell lines, establishing a direct correlation with patient survival outcomes. Silencing the expression of SLC22A17 resulted in reduced cell proliferation, migration, EMT, increased apoptosis, and enhanced autophagy. These effects were accompanied by the inhibition of Akt/mTOR and STAT3 signaling pathways. Moreover, we observed the involvement of the inflammatory cytokine TNF-α, which induced the expression of SLC22A17 in TNBC cell lines and governed various hallmark features of TNBC. Notably, the suppression of SLC22A17 mitigated these processes. Conclusion: In conclusion, this investigation suggests the pivotal role played by SLC22A17 in TNBC and posits its potential as a novel and promising therapeutic target for the management of this formidable disease. Citation Format: Ajaikumar B. Kunnumakkara, Krishan Kumar Thakur. SLC22A17 as a promising target for triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 573.

Abstract 6281: Context dependent role of glucocorticoids in breast cancer

Abstract Glucocorticoids bind to the transcription factor glucocorticoid receptor (GR) and regulate genes in response to cellular metabolism, inflammation, and stress. Although GR has been extensively evaluated in inflammation and metabolic diseases, its role as a therapeutic target in cancer has not been thoroughly studied. Results from studies with another member of the steroid receptor family, androgen receptor (AR), demonstrated that the AR is an oncogene in estrogen receptor (ER)-negative breast cancer, but a tumor suppressor in ER-positive breast cancer. We expected a comparable mechanism with GR in different breast cancer subtypes. In this study, we evaluated the role of GR in various breast cancer subtypes and discerned the mechanism of action. Six breast cancer cell lines and seven patient-derived xenografts (PDXs) were characterized by Western blot for their expression of GR, ER and AR. Proliferation assays were performed in cell lines with a dose-response of a synthetic glucocorticoid, dexamethasone. Subsequently, we performed xenograft studies in cell line xenografts (CDXs) and PDXs. GR was ubiquitously expressed in various cell lines and PDX models. Dexamethasone reduced cell proliferation in ER-positive models, while it increased the proliferation in ER-negative cell lines, suggesting that the GR might have a mechanism of action that is similar to AR. GR antagonist, mifepristone, reversed the effects of dexamethasone. CDX studies in an ER-positive cell line, MCF7 suggested that dexamethasone (10 mpk) inhibited the tumor growth significantly that was better than the standard of care fulvestrant. This result was confirmed in an ER positive PDX model HCI013. Study by Obradović et al, indicates that glucocorticoids have an oncogenic role and furthermore promote breast cancer metastasis in TNBC model thereby validating the subtype and context dependent role of the glucocorticoid receptor. We are currently exploring the mechanism of GR’s context-dependent tumor suppressor and oncogenic role in distinct breast cancer subtypes. Citation Format: Wendy Effah, Suriyan Ponnusamy, Sarah Asemota, Yekta Khosrosereski, Ramesh Narayanan. Context dependent role of glucocorticoids in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6281.

Abstract 5728: YB1 is a novel therapeutic for the treatment of triple negative breast cancer tumors

Abstract Metastatic breast cancer (BC) is the 2nd leading cause of death in women in the US, annually accounting for more than 43,000 deaths and 281,000 new cases of invasive BC. Amongst genetically distinct BC subtypes, those classified as being “triple-negative” (TNBC) are especially devastating due to their highly metastatic behavior, their propensity to recur rapidly, and their low response to standard-of-care therapies. In fact, the acquisition of chemoresistant phenotypes represents the main cause of disease recurrence, metastasis, and death in TNBC patients. Currently, the molecular mechanisms that regulate TNBC progression and metastasis remain unknown, as does the way these metastatic tumors acquire resistance to standard-of-care therapies. We recently established YB1 as a novel driver of these deadly TNBC activities, doing so by stimulating the cancer stem cell phenotype, and by disrupting normal cell cycle progression, therefore promoting therapy resistance and metastasis of TNBC tumors. YB1 is a multifunctional protein that acts as a transcription factor of cancer stem cell genes Nanog, Oct and Sox. Moreover, aberrant activation of YB1 contributes to the metastatic progression of several cancers, including TNBC. Our investigations revealed a major role of YB1 in the regulation of several hallmarks of cancer that drive TNBC tumors progression and metastasis, both in vitro and in preclinical mouse models of TNBC tumors. In extending these discoveries, we now show that aberrant YB1 expression activates oncogenic signaling leading to the dysregulation of cell cycle progression through the regulation of the Cyclin D/CDK4/6 complex signaling and the RB pathway. We also report the identification of a novel small molecule inhibitor, SU056, that specifically targets YB1 and inhibits its oncogenic activity in TNBC cell lines. We further show that the SU056-mediated inhibition of YB1, either as monotherapy or in combination with the CDK4/6 inhibitors, has a significant impact on inhibiting TNBC tumor progression and metastasis. In fact, the SU056-CDK4/6 inhibitors combination showed a synergistic effect when compared to monotherapy, at the same time reducing the toxicity associated with CDK4/6 inhibitors. Mechanistically, our studies revealed that genetic or pharmacologic targeting of YB1 inhibits TNBC tumor progression and metastasis through the regulation cyclin D-CDK4/6-RB pathway and blockade of cell cycle progression. Together, our data support the notion that targeting YB1 represents a potential therapeutic option for the treatment of TNBC, which could be enhanced when combined with standard of care treatment modalities. Citation Format: Wei Wang, Lamyae El Khalki, Neelum Yousaf Zai, Justin Szpendyk, Akram Alkrekshi, Bin Su, Khalid Sossey-Alaoui. YB1 is a novel therapeutic for the treatment of triple negative breast cancer tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5728.

Potential Value of HSP90α in Prognosis of Triple-Negative Breast Cancer.

BACKGROUND Triple-negative breast cancer (TNBC) is a distinct subtype of breast cancer, accounting for 12-18% of all breast cancer cases. It exhibits high heterogeneity and aggressiveness, resulting in a poorer prognosis with a high risk of early recurrence and metastasis. Due to the lack of expression of estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptor 2 (HER2), as well as insensitivity to endocrine therapy, determining a standard treatment for TNBC is challenging. The identification of potential prognostic biomarkers is crucial for developing personalized treatment strategies for patients. MATERIAL AND METHODS Our study investigated the potential value of HSP90a in TNBC prognosis. A retrospective analysis was conducted on 127 TNBC patients and 127 Healthy controls from March 1, 2019 to July 31, 2022. Venous blood was collected and tested for HSP90alpha, CEA, CA199, and CA125, and we recorded the clinical characteristics of the patients, including age, BMI, alcohol consumption status, surgical history, CEA level, CA199 level, CA125 level, HSP90alpha level, tumor size, distant metastases, lymph node metastasis, and TNM stage. Univariate and multivariate methods were used to screen independent risk factors for progression-free survival (PFS) and overall survival (OS). RESULTS HSP90alpha is not only upregulated in TNBC but is also highly correlated with lymph node metastasis and TNM stage. The results of multivariate analysis showed that distant metastasis, TNM stage and HSP90a level were independent factors associated with PFS. BMI, tumor size, TNM stage, surgical history, and HSP90a level were independent factors influencing OS. CONCLUSIONS Our research findings demonstrate a significant association between high HSP90alpha expression and adverse clinical features, suggesting a poorer prognosis for TNBC patients.

Metastatic profiles and survival differences between infiltrating ductal carcinoma and infiltrating lobular carcinoma in invasive breast cancer

BackgroundIn this study, we conducted a comprehensive evaluation of metastatic profiles and survival outcomes in patients with infiltrating ductal carcinoma (IDC) and infiltrating lobular carcinoma (ILC) treated at our university hospital center. MethodsWe collected and analyzed data from all patients diagnosed with invasive breast cancer at our center between January 1, 2007, and 31 December 2014. We specifically compared three subgroups: patients with IDC, patients with ILC and patients with mixed carcinoma, which is a combination of IDC and ILC. ResultsAmong the 1963 patients treated for invasive breast cancer in our center during the study period, 1435 had IDC, 466 had ILC, and 59 had mixed carcinoma. The incidence of patients with at least one positive axillary lymph node differed significantly: 40 % for IDC, 36 % for ILC, and 45 % for mixed carcinoma (p = 0.001). However, there was no significant difference in the mean number of positive nodes (p = 0.1633). The occurrence of distant metastases was lower in patients with ILC (p = 0.04), particularly in the case of brain metastases (p = 0.01), although there was no difference in bone or visceral metastatic sites. Patients with ILC exhibited a longer mean time to metastasis from the initial diagnosis of invasive breast carcinoma. Overall survival (p = 0.0525) and survival without locoregional recurrence (p = 0.026) were significantly different. Specifically, the 5-year overall survival rates for IDC, ILC, and mixed carcinoma were approximately 95 %. Distance metastatic-free survival at 5 years was 85 % for IDC, 91 % for ILC, and 87 % for mixed carcinoma (p = 0.00506). ConclusionOur findings indicate variations in the distribution of distant metastatic sites among patients with IDC, ILC, and mixed carcinoma, as well as differences in survival outcomes. This study sheds light on the unique characteristics and clinical implications associated with these two distinct subtypes of invasive breast cancer.

N-glycan profiling of tissue samples to aid breast cancer subtyping

Breast cancer is a highly heterogeneous disease. Its intrinsic subtype classification for diagnosis and choice of therapy traditionally relies on the presence of characteristic receptors. Unfortunately, this classification is often not sufficient for precise prediction of disease prognosis and treatment efficacy. The N-glycan profiles of 145 tumors and 10 healthy breast tissues were determined using Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry. The tumor samples were classified into Mucinous, Lobular, No-Special-Type, Human Epidermal Growth Factor 2 + , and Triple-Negative Breast Cancer subtypes. Statistical analysis was conducted using the reproducibility-optimized test statistic software package in R, and the Wilcoxon rank sum test with continuity correction. In total, 92 N-glycans were detected and quantified, with 59 consistently observed in over half of the samples. Significant variations in N-glycan signals were found among subtypes. Mucinous tumor samples exhibited the most distinct changes, with 28 significantly altered N-glycan signals. Increased levels of tri- and tetra-antennary N-glycans were notably present in this subtype. Triple-Negative Breast Cancer showed more N-glycans with additional mannose units, a factor associated with cancer progression. Individual N-glycans differentiated Human Epidermal Growth Factor 2 + , No-Special-Type, and Lobular cancers, whereas lower fucosylation and branching levels were found in N-glycans significantly increased in Luminal subtypes (Lobular and No-Special-Type tumors). Clinically normal breast tissues featured a higher abundance of signals corresponding to N-glycans with bisecting moiety. This research confirms that histologically distinct breast cancer subtypes have a quantitatively unique set of N-glycans linked to clinical parameters like tumor size, proliferative rate, lymphovascular invasion, and metastases to lymph nodes. The presented results provide novel information that N-glycan profiling could accurately classify human breast cancer samples, offer stratification of patients, and ongoing disease monitoring.

The homeoprotein HOXB2 limits triple-negative breast carcinogenesis via extracellular matrix remodeling.

Homeobox genes and their encoded DNA-binding homeoproteins are master regulators of development. Consequently, these homeotic elements may regulate key steps in cancer pathogenesis. Here, using a combination of in silico analyses of large-scale patient datasets, in vitro RNAi phenotyping, and in vivo validation studies, we investigated the role of HOXB2 in different molecular subtypes of human breast cancer (BC). The gene expression signatures of HOXB2 are different across distinct BC subtypes due to various genetic alterations, but HOXB2 was specifically downregulated in the aggressive triple-negative subtype (TNBC). We found that the reduced expression of HOXB2 was correlated with the metastatic abilities (epithelial-to-mesenchymal transition) of TNBC cells. Further, we revealed that HOXB2 restrained TNBC aggressiveness by ECM organization. HOXB2 bound to the promoter regions of MATN3 and ECM2 and regulated their transcription levels. Forced expression of HOXB2 effectively prevented TNBC progression and metastasis in a mouse xenograft model. Reduction of HOXB2 and the HOXB2/MATN3/ECM2 transcriptional axis correlated with poor survival in patients with various cancers. Further, we found the long non-coding RNA HOXB-AS1 in complex with SMYD3, a lysine methyltransferase, as an epigenetic switch controlling HOXB2 expression. Overall, our results indicate a tumor-suppressive role of HOXB2 by maintaining ECM organization and delineate potential clinical utility of HOXB2 as a marker for TNBC patients.

The Clinicopathological Features and Prognostic Significance of HER2-Low in Early Breast Tumors Patients Prognostic Comparison of HER-Low and HER2-Negative Breast Cancer Stratified by Hormone Receptor Status

Introduction. There has been increased interest in HER2-low breast tumors recently, as these tumors may have distinct clinical and molecular characteristics compared to HER2-negative and HER2-positive tumors. A new nomenclature has been proposed for HER2 1+ and HER2 2+ tumors that are confirmed negative according to fluorescence in situ hybridization (FISH). These tumors are now referred to as HER2-low, and it is thought that they may represent a distinct subtype of breast cancer that warrants further investigation. In this study, we aimed to evaluate the clinicopathological characteristics and prognostic impact of this particular subtype in a North-African context where HER2-low breast cancer is a relatively understudied subtype, particularly in non-Western populations. Methods. We conducted a retrospective cohort study on 1955 breast tumors in Moroccan patients over 10 years, collected at the Pathology Department of Ibn Rochd University Hospital in Casablanca and at the pathology department of Hassan II University Hospital in Fes. We elaborated on their complete immunohistochemical profile based on the main breast cancer biomarkers: Ki-67, HER2, estrogen, and progesterone receptors. Their overall survival and disease free survival data were also retrieved from their respective records. Results. Out of 1955 BC patients, 49.3% were classified as HER2-low; of which 80.7% and 19.2% were hormone receptors positive and negative, respectively. The clinicopathologic features indicate that HER2-low subtype tumors behave much more like HER2-positive than HER2-negative tumors. The survival analysis showed that the HER2-low subtype-belonging patients present significantly the poorest prognosis in disease-free survival ( p = 0.003 ) in comparison with HER2-negative ones. When considering the hormonal status, hormonal-dependent tumors show a significant difference according to HER2 subtypes in disease-free survival ( p &lt; 0.001 ). Yet no significant difference was shown among hormonal negative tumors. Moreover, patients with hormonal positive tumors and simultaneously belonging to the HER2-low subgroup present a significantly good prognosis in overall survival compared to the ones with hormonal negative tumors ( p = 0.008 ). Conclusion. Our study has shown that the HER2-low phenotype is common among hormone-positive patients. The clinicopathological features and prognostic data indicate that the hormonal receptors effect and HER2 heterogeneity are crucial factors to consider. It is important to note that this particular subgroup is different from the HER2-negative one and should not be treated in the same way. Therefore, this study offers a new perspective in the management of HER2-low patients and can serve as a basis for future prospective analyses.

The Role of the Tumor Microenvironment in Triple-Positive Breast Cancer Progression and Therapeutic Resistance.

Breast cancer (BRCA) is a highly heterogeneous systemic disease. It is ranked first globally in the incidence of new cancer cases and has emerged as the primary cause of cancer-related death among females. Among the distinct subtypes of BRCA, triple-positive breast cancer (TPBC) has been associated with increased metastasis and invasiveness, exhibiting greater resistance to endocrine therapy involving trastuzumab. It is now understood that invasion, metastasis, and treatment resistance associated with BRCA progression are not exclusively due to breast tumor cells but are from the intricate interplay between BRCA and its tumor microenvironment (TME). Accordingly, understanding the pathogenesis and evolution of the TPBC microenvironment demands a comprehensive approach. Moreover, addressing BRCA treatment necessitates a holistic consideration of the TME, bearing significant implications for identifying novel targets for anticancer interventions. This review expounds on the relationship between critical cellular components and factors in the TPBC microenvironment and the inception, advancement, and therapeutic resistance of breast cancer to provide perspectives on the latest research on TPBC.

Causal pathways linking polycystic ovary syndrome to distinct breast cancer subtypes through mediator factors: a multivariable mendelian randomization analysis

Polycystic ovary syndrome (PCOS) is an endocrine disorder characterized by ovarian cysts, high androgen levels, and irregular menstruation. The causality between PCOS and breast cancer (BC) has been widely discussed as they share a significant intersection in clinical manifestations. Previous epidemiological studies have not provided consistent conclusions in association between PCOS and BC, while mendelian randomization (MR) analyses have confirmed the causality between PCOS and estrogen receptor-positive breast cancer (ER + BC), but among a series of clinical manifestations resulting from PCOS, which related traits mediate the causal effect remains unknown. In this study, we conducted multivariable mendelian randomization (MVMR) analysis to explore the potential mediator variables in the mechanism linking PCOS to distinct subtypes of BC, and calculated the mediating effects proportion. We analyzed 13 PCOS-related traits and found that age at menopause may mediate PCOS-induced ER + BC (with -4.82% proportion) with a weak protective effect through the repair of DNA double-strand breaks by homologous recombination. This study helps to better comprehend the shared mechanisms contributing to the development of both PCOS and BC, and to screen high-risk populations for BC and take appropriate preventive measures.

Digital mammography and digital breast tomosynthesis for detecting invasive lobular and ductal carcinoma.

Invasive lobular carcinoma (ILC) is a distinct histological subtype of breast cancer that can make early detection with mammography challenging. We compared imaging performance of digital breast tomosynthesis (DBT) to digital mammography (DM) for diagnoses of ILC, invasive ductal carcinoma (IDC), and invasive mixed carcinoma (IMC) in a screening population. We included screening exams (DM; n = 1,715,249 or DBT; n = 414,793) from 2011 to 2018 among 839,801 women in the Breast Cancer Surveillance Consortium. Examinations were followed for one year to ascertain incident ILC, IDC, or IMC. We measured cancer detection rate (CDR) and interval invasive cancer rate/1000 screening examinations for each histological subtype and stratified by breast density and modality. We calculated relative risk (RR) for DM vs. DBT using log-binomial models to adjust for the propensity of receiving DBT vs. DM. Unadjusted CDR per 1000 mammograms of ILC overall was 0.33 (95%CI: 0.30-0.36) for DM; 0.45 (95%CI: 0.39-0.52) for DBT, and for women with dense breasts- 0.33 (95%CI: 0.29-0.37) for DM and 0.54 (95%CI: 0.43-0.66) for DBT. Similar results were noted for IDC and IMC. Adjusted models showed a significantly increased RR for cancer detection with DBT compared to DM among women with dense breasts for all three histologies (RR; 95%CI: ILC 1.53; 1.09-2.14, IDC 1.21; 1.02-1.44, IMC 1.76; 1.30-2.38), but no significant increase among women with non-dense breasts. DBT was associated with higher CDR for ILC, IDC, and IMC for women with dense breasts. Early detection of ILC with DBT may improve outcomes for this distinct clinical entity.

Biological differences between normal and cancer-associated fibroblasts in breast cancer

BackgroundCancer-associated fibroblasts (CAFs) constitute the primary constituents of the tumor microenvironment (TME) and exert significant influences on cancer progression. However, adequate comprehension of CAF profiles in breast cancer, as well as the precise mechanisms underlying their promotion of cancer, remains lacking. ObjectivesTo discerns the biological differences between normal fibroblasts (NFs) and CAFs in breast cancer and explore the underlying mechanism. MethodsThree pairs of CAFs and NFs were isolated from breast cancer patients of diverse subtypes who had not undergone prior radiotherapy or chemotherapy. Morphological characteristics of CAFs and NFs were assessed through optical and electron microscopy, their biological attributes were examined using cell counting kits and transwell assays, and their impact on breast cancer cells was simulated using a coculture system. Furthermore, the miRNA profiles of CAFs and NFs were sequenced via an Illumina HiSeq 2500 platform. ResultsCAFs exhibited higher growth rate and motility than NFs and a stronger potential to promote the malignancy of breast cancer cells. RNA sequencing of both NFs and CAFs revealed differentially expressed miRNAs with notable variability among distinct patients within their NFs and CAFs, while the enrichment of the target genes of differentially expressed miRNAs within both GO terms and KEGG pathways demonstrated significant similarity across patients with different profiles. ConclusionCAFs have greater malignancy and higher potential to influence the growth, migration, invasion and chemoresistance of cocultured breast cancer cells than NFs. In addition, the miRNAs that are differentially expressed in CAFs when compared to NFs display substantial variability across patients with distinct breast cancer subtypes, while the enrichment of target genes regulated by these miRNAs, within GO terms and KEGG pathways, remains remarkably consistent among patients with varying profiles.

Assessing the Antiproliferative Potential of a Novel Combretastatin A4 Derivative via Modulating Apoptosis, MAPK/ERK and PI3K/AKT Pathways in Human Breast Cancer Cells.

Breast cancer is the most predominant tumor in women. Even though current medications for distinct breast cancer subtypes are available, the non-specificity of chemotherapeutics and chemoresistance imposes major obstacles in breast cancer treatment. Although combretastatin A-4 (CA-4) has been well-reported to have potential anticancer activity, in vivo studies of CA-4 reveal a decrease in its activity. In this respect, a series of CA-4 analogues have been designed, from which one analog [(1-(3-chloro-4-fluorophenyl)-N-(2methoxyphenyl)-5-(3,4,5-trimethoxyphenyl)-1H-1,2,4-triazole-3-carboxamide, C25H22ClFN4O5] showed drastic cytotoxicity against breast cancer cells. Therefore, this research focused on investigating the in vitro molecular mechanism underlying the cytotoxicity of the CA-4 analogue, particularly the MAPK/ERK as well as PI3K/AKT pathways as attractive therapeutic targets in breast cancer. The cell viability of MCF-7, MDA-MB231, and MDA-MB453 was assessed after treatment with the CA-4 analogue, and apoptosis was analyzed via Annexin V-FITC/PI dual staining. MAPK/ERK and PI3K/AKT were thoroughly assessed using western blotting. Real-time PCR was used to estimate apoptosis-related markers, including the P53, Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl2) genes. The CA-4 analogue reduced the survival of all cancerous cells in a concentration-dependent manner and induced apoptosis through the mitochondrial pathway (39.89 ± 1.5%, 32.82 ± 0.6%, and 23.77 ± 1.1% in MCF-7, MDA-MB231, and MDA-MB453 cells), respectively. The analogue also attenuated the expression of pMEK1/2/t-MEK1/2, p-ERK1/2/t-ERK1/2, p-PI3K/t-PI3K, and p-AKT/t-AKT proteins in all three cancer cell lines in a time-dependent manner. Furthermore, the CA-4 analogue upregulated the expression of the P53 gene and dramatically increased the ratio of Bax/Bcl2 genes. The enhanced cytotoxicity can be attributed to substituting the hydroxyl group in CA-4 with chlorine in the meta-position of ring B, substituting the para-methoxy group in CA-4 with fluorine in the analogue, and lastly, introducing an extension to the compound's structure (ring C). Therefore, CA-4 analogue can attenuate the proliferation of human breast cancer cells by inducing apoptosis and simultaneously suppressing the MAPK/ERK and PI3K/AKT pathways.