Early Breast Cancer Progression Research Articles

The role of tumor-associated neutrophils in early luminal HER2-negative breast cancer progression

BACKGROUND: Luminal HER2-negative breast cancer is the most common type of tumor in women diagnosed with early-stage breast cancer. Stromal cells and immune cells in tumor microenvironment have been reported to play a significant role in cancer prognosis. The prognostic role of tumor-associated neutrophils in early breast cancer remains mostly unclear. AIM: To study predictive role tumor-associated neutrophils in early luminal HER2-negative breast cancer. MATERIALS AND METHODS: The dataset consisted of 60 patients with early luminal HER2-negative breast cancer treated in S.P. Botkin City Clinical Hospital (Moscow, Russia). We first estimated basic morphological signs: tumor size, tumor grade (by Nottingham Histologic Score), tumor-infiltrating lymphocytes, lymphovascular invasion, hormonal receptors status, proliferative index, regional lymph nodes status. The expression of intratumoral neutrophils was studied using immunohistochemistry with CD15. RESULTS: High tumor-associated neutrophils concentration was correlated with tumor size, high grade tumors, proliferative index, tumor-infiltrating lymphocytes, lymphovascular invasion and positive regional lymph nodes. CONCLUSION: Tumor-associated neutrophils predicted a worse prognosis in early luminal HER2-negative breast cancer.

A population-based study on trajectories of HER2 status during neoadjuvant chemotherapy for early breast cancer and metastatic progression

BackgroundThis study aimed to investigate the distribution and changes of HER2 status in untreated tumours, in residual disease and in metastasis, and their long-term prognostic implications.MethodsThis is a population-based cohort study of patients treated with neoadjuvant chemotherapy for breast cancer during 2007–2020 in the Stockholm–Gotland region which comprises 25% of the entire Swedish population. Information was extracted from the National Breast Cancer Registry and electronic patient charts to minimize data missingness and misclassification.ResultsIn total, 2494 patients received neoadjuvant chemotherapy, of which 2309 had available pretreatment HER2 status. Discordance rates were 29.9% between primary and residual disease (kappa = 0.534), 31.2% between primary tumour and metastasis (kappa = 0.512) and 33.3% between residual disease to metastasis (kappa = 0.483). Adjusted survival curves differed between primary HER2 0 and HER2-low disease (p < 0.001), with the former exhibiting an early peak in risk for death which eventually declined below the risk of HER2-low. Across all disease settings, increasing the number of biopsies increased the likelihood of detecting HER2-low status.ConclusionHER2 status changes during neoadjuvant chemotherapy and metastatic progression, and the long-term behaviours of HER2 0 and HER2-low disease differ, underscoring the need for obtaining tissue biopsies and for extended follow-up in breast cancer studies.

Surface-enhanced Raman scattering-based identification of breast cancer progression using extracellular vesicles-derived integrin α6β4

Detection of progression is of great importance to breast cancer treatment and can benefit patients. Limited by current detection technologies and biomarkers, early breast cancer progression diagnosis remains challenging. Researchers have found blood extracellular vesicles (EVs)-derived integrin α6β4 directly facilitate progression in breast cancer, enabling cancer detection. However, EVs size and heterogeneity hinder protein detection, masked by abundant background EVs. Hence, novel tools for efficient detection of EVs with high selectivity and low interference are significantly desired. Here, a new silver-coated gold nanorods SERS probe, termed as Au@Ag@IDA-B/4MSTP, based on DNA aptamer was established for the detection of integrin α6β4 derived from EVs. Validation of the Au@Ag@IDA-B/4MSTP probes using cell-culture-derived EVs revealed a LOD of 23 particles/μL for EVs detection. This tool was further confirmed to mimic the real state of cancer with subcutaneous tumor model and lung metastasis model in mice. With 10 μL of blood plasma and simple Raman analysis process, the test achieved 85.7 % sensitivity and 83.3 % specificity. Moreover, our method achieves a simplified approach that expedites the detection process. These results demonstrate the good detection performance of Au@Ag@IDA-B/4MSTP probes for EVs integrin α6β4, and suggest that this non-invasive approach could be a promising tool for early detection of breast cancer progression.

MTOR inhibition abrogates human mammary stem cells and early breast cancer progression markers

BackgroundMammary physiology is distinguished in containing adult stem/progenitor cells that are actively amending the breast tissue throughout the reproductive lifespan of women. Despite their importance in both mammary gland development, physiological maintenance, and reproduction, the exact role of mammary stem/progenitor cells in mammary tumorigenesis has not been fully elucidated in humans or animal models. The implications of modulating adult stem/progenitor cells in women could lead to a better understanding of not only their function, but also toward possible breast cancer prevention led us to evaluate the efficacy of rapamycin in reducing mammary stem/progenitor cell activity and malignant progression markers.MethodsWe analyzed a large number of human breast tissues for their basal and luminal cell composition with flow cytometry and their stem and progenitor cell function with sphere formation assay with respect to age and menopausal status in connection with a clinical study (NCT02642094) involving a low-dose (2 mg/day) and short-term (5–7 days) treatment of the mTOR inhibitor sirolimus. The expression of biomarkers in biopsies and surgical breast samples were measured with quantitative analysis of immunohistochemistry.ResultsSirolimus treatment significantly abrogated mammary stem cell activity, particularly in postmenopausal patients. It did not affect the frequency of luminal progenitors but decreased their self-renewal capacity. While sirolimus had no effect on basal cell population, it decreased luminal cell population, particularly in postmenopausal patients. It also significantly diminished prognostic biomarkers associated with breast cancer progression from ductal carcinoma in situ to invasive breast cancer including p16INK4A, COX-2, and Ki67, as well as markers of the senescence-associated secretary phenotype, thereby possibly functioning in preventing early breast cancer progression.ConclusionOverall, these findings indicate a link from mTOR signaling to mammary stem and progenitor cell activity and cancer progression.Trial registration This study involves a clinical trial registered under the ClinicalTrials.gov identifier NCT02642094 registered December 30, 2015.

Surrogate endpoints for HTA decisions of breast cancer drugs: utility and pitfalls.

Health technology assessment (HTA) of cancer drugs is important to identify whether drugs should be publicly funded. With increasing use of surrogate end points in clinical trials including breast cancer, a review of literature was done to synthesize evidence for validation of these surrogate end points and their potential role in HTA decisions pertaining to breast cancer. Disease free survival (DFS) in human epidermal receptor 2 (HER2) positive early breast cancer remains the only validated surrogate end point. Other surrogate end points like pathological complete response (pCR) and event free survival (EFS) in early breast cancer (EBC) and objective response rate (ORR) and progression free survival (PFS) in advanced disease have not been validated for overall survival (OS). Moreover, surrogate end points for quality of life (QOL) have not been established and drugs that improve PFS can have detrimental effect on QOL. End points like pCR have excellent prognostic utility in individual patients but have weak correlation with survival at trial level. Most surrogate end points used in breast cancer do not predict OS or QOL which makes it challenging to use them for decisions regarding public funding of cancer drugs. These findings are relevant to HTA agencies prior to making drug reimbursement decisions.

ADAMTS3 restricts cancer invasion in models of early breast cancer progression through enhanced fibronectin degradation

Proteases have long been associated with cancer progression, due to their ability to facilitate invasion upon matrix remodelling. However, proteases are not simply degraders of the matrix, but also play fundamental roles in modulating cellular behaviour through the proteolytic processing of specific substrates. Indeed, proteases can elicit both pro- and anti- tumorigenic effects depending on context. Using a heterocellular spheroid model of breast cancer progression, we demonstrate the repressive function of myoepithelial ADAMTS3, with its loss directing myoepithelial-led invasion of luminal cells through a physiologically relevant matrix. Degradomic analysis, using terminal amine isotopic labelling of substrates (TAILS), combined with functional assays, implicate ADAMTS3 as a mediator of fibronectin degradation. We show further that loss of ADAMTS3 enhances levels of fibronectin in the microenvironment, promoting invasion through canonical integrin α5β1 activation. Our data highlight a tumour suppressive role for ADAMTS3 in early stage breast cancer, and contribute to the growing evidence that proteases can restrain cancer progression.

Drug-resistant Stem Cell Models for the Hormone-responsive Luminal A Breast Cancer

Background: Progression of early stage breast cancer to advanced stage metastatic disease represents a major cause of death in women. The Luminal A breast cancer subtype exhibits acceptable response to Chemo-endocrine and targeted therapy. However, these treatment options are associated with intrinsic/acquired therapy resistance and emergence chemo-resistant cancer initiating stem cell population, and resultant progression to advanced stage metastatic disease. These limitations emphasize an unmet need for the development of reliable models for cancer stem cells that facilitate identification of efficacious therapeutic alternatives. Documented human consumption, low systemic toxicity, preclinical cancer growth inhibitory efficacy and stem cell targeting efficacy of natural products, such as dietary phytochemicals and nutritional herbs, provide mechanistic leads for these agents as testable therapeutic alternatives. Objectives: The objectives of the present review are to i.) Provide a systematic discussion of published evidence relevant conceptual background of conventional/targeted therapy and nutritional herbs as testable alternatives, ii.) Growth inhibitory efficacy of nutritional herbs in a cellular model for the Luminal A breast cancer, iii.) Breast cancer stem cell biology and stem cell models for therapy-resistant breast cancer, and iv.) Future research directions. Conclusions: Collectively, all the elements discussed in the present review validate mechanism-based experimental approaches to identify and prioritize potential therapeutic alternatives. Future Research: This review provides a rationale for investigations on patient-derived tumor samples that may minimize extrapolation of the preclinical data for their clinical relevance and translatability.

Nanoscale Tracking Combined with Cell-Scale Microrheology Reveals Stepwise Increases in Force Generated by Cancer Cell Protrusions.

In early breast cancer progression, cancer cells invade through a nanoporous basement membrane (BM) as a first key step toward metastasis. This invasion is thought to be mediated by a combination of proteases, which biochemically degrade BM matrix, and physical forces, which mechanically open up holes in the matrix. To date, techniques that quantify cellular forces of BM invasion in 3D culture have been unavailable. Here, we developed cellular-force measurements for breast cancer cell invasion in 3D culture that combine multiple-particle tracking of force-induced BM-matrix displacements at the nanoscale, and magnetic microrheometry of localized matrix mechanics. We find that cancer-cell protrusions exert forces from picoNewtons up to nanoNewtons during invasion. Strikingly, the protrusions extension involves stepwise increases in force, in steps of 0.2 to 0.5 nN exerted from every 30 s to 6 min. Thus, this technique reveals previously unreported dynamics of force generation by invasive protrusions in cancer cells.

Abstract 861: Nuclear translocation of Axl during early breast cancer progression

Abstract Axl is a receptor tyrosine kinase (RTK) that is activated by its ligand Gas6 and regulates proliferation, cell survival, and clearance of apoptotic cells in both normal physiology and a number of disease states. In breast cancer, Axl is overexpressed in Her2+ and triple-negative breast cancers and is associated with resistance to RTK targeted therapies. Recent studies have shown that upon kinase inhibition, the Axl intracellular domain (ICD) can translocate to the nucleus, however, the biological significance and functions for nuclear Axl are poorly understood. Furthermore, a functional role for Axl during ductal carcinoma in situ (DCIS) progression, a requisite step for invasive breast cancer, has not been established. To address whether Axl mediates localized invasion during DCIS progression, Axl was deleted in a DCIS cell line (MCF10A-DCIS.com) using a CRISPR-Cas9 approach. Deletion of Axl shows a significant decrease in progression to invasive cancer in vivo, which is accompanied by decreased proliferation, however microinvasion is unchanged as compared to wildtype. Analysis of patient samples of pure DCIS, DCIS with microinvasion, and DCIS with invasive cancer shows a significant increase in Axl expression in patients with evidence of invasion. Interestingly, there is a significant increase in nuclear Axl in all patient samples with evidence of invasion as compared to normal breast or pure DCIS, suggesting an important role for Axl-ICD in progression to invasive cancer. Soft agar assays using normal cells (MCF10A) shows that while full length Axl (Axl-FL) is sufficient to induce colonies, Axl-ICD-transduced cells do not form colonies, suggesting that Axl-ICD alone does not have oncogenic activity. However, Axl-ICD significantly increases colonies in DCIS cells, suggesting that the ICD is important in the progression of transformed cells. Ongoing studies are aimed at identifying transcriptional targets of Axl-ICD in DCIS cells. These studies will advance our understanding of how Axl mediates breast cancer progression and will have critical implications for ongoing therapeutic strategies aimed at targeting Axl. This work is supported by NIH R01CA212518 (H.L.M.) and Susan G. Komen CCR1637765 (H.L.M.). Citation Format: Darby R. Graham, Kelly D. Hebert, Emma E. Newton, Angelica M. Gomes, Fariba Behbod, Heather L. Machado. Nuclear translocation of Axl during early breast cancer progression [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 861.

Involvement of miR-3648 mediated APC2 1 dysregulation in early onset and breast cancer progression

Multiple cancers arise due to aberrations in the Wnt signaling pathway. Several miRNAs modulate the integral components of the wingless integrated (Wnt) signaling pathway. miR-3648 is a human-specific miRNAs that is of particular interest due to its minimal off-targeting effect. In this study, we investigated the expression of miR-3648 and APC2 in breast cancer patients of Pakistan. Correlations of miR-3648 and APC2 expression with clinico-pathological features and breast cancer subtypes were observed in tissue samples by means of quantitative real time PCR. Our results showed that miR-3648 was relatively downregulated in Luminal A subtype, with corresponding upregulation of APC2 in these patients. Moreover, the transcript levels of both miR-3648 and APC2 were found to be inversely regulated in breast cancer women presented with early disease onset, pre-menopause, low tumor grade, early clinical stage, absence of nodal invasion and metastasis, further suggesting the molecular interplay of these molecules in breast cancer development and progression.

Abstract P1-10-06: Effect of aging and mTOR inhibition on human mammary stem cells and early breast cancer progression markers

Abstract Ductal carcinoma in situ (DCIS) is the most common form of breast cancer and is a predecessor to invasive carcinoma development. The origins for early breast cancer have been attributed to aberrant single cells, which may include adult stem and progenitor cells. We performed a window trial with mTOR inhibitor sirolimus in patients with atypical ductal hyperplasia (ADH) or DCIS and investigated the epithelial populations in adjacent normal and ADH/DCIS breast tissues along with their residing stem and progenitor cell activity. Differences associated with age, menopausal status, and treatment by sirolimus have also been explored. While the mammary epithelial populations were seen to be unchanged in aging, we found that age correlates with a decline in stem cell activity. mTOR inhibition was also able to abrogate mammary stem cell activity and decrease luminal progenitor passaging lifespan, particularly in postmenopausal patients. While mTOR inhibition had no effect on myoepithelial populations, it did decrease premenopausal luminal cell populations and reduced prognostic markers associated with breast cancer progression from DCIS to invasive breast cancer. These markers include p16INK4A, COX-2, and Ki67, which were reduced in DCIS breast tissue from patients administered with sirolimus as shown through quantitative analysis of immunohistochemistry. Overall, these findings indicate a link from mTOR signaling to mammary stem cell activity and cancer progression. mTOR inhibitors may have potential for breast cancer prevention. Citation Format: Larry E Broome, Hakim Bouamar, Kate Lathrop, Ismail Jatoi, Andrew Brenner, Michael Garcia, Alia Nazarullah, Karla Moncada, Virginia Kaklamani, Lu-Zhe Sun. Effect of aging and mTOR inhibition on human mammary stem cells and early breast cancer progression markers [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 P1-10-06.

MTOR Inhibition Abrogates Human Mammary Stem Cells and Early Breast Cancer Progression Markers

mTOR Inhibition Abrogates Human Mammary Stem Cells and Early Breast Cancer Progression Markers

Expression of CCL2/CCR2 signaling proteins in breast carcinoma cells is associated with invasive progression

Ductal carcinoma in situ (DCIS) is the most common type of pre-invasive breast cancer diagnosed in women. Because the majority of DCIS cases are unlikely to progress to invasive breast cancer, many women are over-treated for DCIS. By understanding the molecular basis of early stage breast cancer progression, we may identify better prognostic factors and design treatments tailored specifically to the predicted outcome of DCIS. Chemokines are small soluble molecules with complex roles in inflammation and cancer progression. Previously, we demonstrated that CCL2/CCR2 chemokine signaling in breast cancer cell lines regulated growth and invasion through p42/44MAPK and SMAD3 dependent mechanisms. Here, we sought to determine the clinical and functional relevance of CCL2/CCR2 signaling proteins to DCIS progression. Through immunostaining analysis of DCIS and IDC tissues, we show that expression of CCL2, CCR2, phospho-SMAD3 and phospho-p42/44MAPK correlate with IDC. Using PDX models and an immortalized hDCIS.01 breast epithelial cell line, we show that breast epithelial cells with high CCR2 and high CCL2 levels form invasive breast lesions that express phospho-SMAD3 and phospho-p42/44MAPK. These studies demonstrate that increased CCL2/CCR2 signaling in breast tissues is associated with DCIS progression, and could be a signature to predict the likelihood of DCIS progression to IDC.

The role of biomarkers in the early diagnostics of breast cancer

One of the main priorities in modern oncology is the identification and clinical application of biomarkers that can be helpful in the diagnostics and prognostication of cancer. The aim of this article was to review biomarkers for early diagnosis and prediction of prognosis of breast cancer. There were reviewed three main groups of biomarkers in this article: familial breast cancer biomarkers with high and low penetration (BRCA1, BRCA2, TP53, etc.), biomarkers of breast cancer molecular subtypes (luminal A and luminal B, HER2/neu, basal and low in claudine) and biomarkers of early stage breast cancer progression (multigenic panels).

LINC00885 a Novel Oncogenic Long Non-Coding RNA Associated with Early Stage Breast Cancer Progression.

Long intergenic non-protein coding RNA 885 (LINC00885) was identified as significantly upregulated in breast ductal carcinoma in situ (DCIS). The aim of this study was to characterize the phenotypic effects and signaling pathways modulated by LINC00885 in non-invasive and invasive breast cancer models. We determined that LINC00885 induces premalignant phenotypic changes by increasing cell proliferation, motility, migration and altering 3D growth in normal and DCIS breast cell lines. Transcriptomic studies (RNA-seq) identified the main signaling pathways modulated by LINC00885, which include bioprocesses related to TP53 signaling pathway and proliferative signatures such as activation of EREG, EGFR and FOXM1 pathways. LINC00885 silencing in breast cancer lines overexpressing this lncRNA leads to downregulation of proliferation related transcripts such as EREG, CMYC, CCND1 and to significant decrease in cell migration and motility. TCGA-BRCA data analyses show an association between high LINC00885 expression and worse overall survival in patients with primary invasive breast carcinomas (p = 0.024), suggesting that the pro-tumorigenic effects of LINC00885 overexpression persist post-invasion. We conclude that LINC00885 behaves as a positive regulator of cell growth both in normal and DCIS breast cells possibly operating as a ceRNA and representing a novel oncogenic lncRNA associated with early stage breast cancer progression.

Abstract 1583: The tumor immune microenvironment in early breast cancer progression

Abstract Ductal carcinoma in situ (DCIS), comprising 20% of all breast cancer diagnoses, is a neoplastic proliferation of epithelial cells confined to the luminal compartment of mammary ducts, which precedes invasive ductal carcinoma (IDC) formation. Although not all DCIS progresses to IDC, there remains no reliable method to determine which DCIS lesions are most likely to become invasive. Recent studies on paired HER2+ and triple negative DCIS and IDC, indicate biological modulation of the microenvironment as a possible mechanism of progression. In particular, the immune microenvironment plays a crucial role in modulating cancer cell behavior and invasion potential. The role of the immune microenvironment in luminal (ER/PR+, HER2+/-) DCIS progression to IDC has not been well studied, however it is an area of keen interest given that this subtype accounts for 50-65% of all diagnosed breast cancers. To address this gap in knowledge, we employed imaging mass cytometry (IMC) to evaluate the tumor immune microenvironment of co-existing luminal DCIS and IDC in patient tumor samples. IMC allows for the comprehensive analysis of up to 35 different metal-tagged antibodies simultaneously, by coupling laser ablation of the tissue with mass cytometry, while maintaining spatial integrity. Using a panel of epithelial, immune and signaling markers, we characterized the tumor microenvironment of DCIS and IDC tumor components across multiple patient samples, investigating the differences between IDC, DCIS adjacent to IDC, and distant DCIS that is further away from the IDC component, while also controlling for inter-individual heterogeneity. A segmentation mask for each image was generated using a combination of Ilastik, CellProfiler, and ImageJ open source platforms. Single-cell information was extracted and utilized to categorize cells by phenotypes and reconstruct spatial organization maps. Immune phenotype composition, cell-cell interactions, and tumor infiltrating lymphocytes (TILs) were evaluated, and nearest neighbor analysis was performed. In addition to a significant increase in TILs within IDC tumors, we observe a switch towards an immunosuppressed microenvironment between DCIS (both adjacent and distant) and IDC. This is evidenced by an increase in T regulatory cell (Treg) infiltration and Treg-CD8 T cell interactions, as well as a decrease in the proportion of CD8 T cells observed in IDC tumors. Furthermore, there is an increase in T cell infiltration in adjacent DCIS, when compared to both IDC and distant DCIS. This may indicate a more activated immune microenvironment phenotype in these tumors. Results from this novel study will give insight into how the overall immune landscape is reprogrammed during DCIS progression, and may contribute to efforts to better predict early-stage breast cancer progression. Citation Format: Alyssa Victoria Francis, Luke McCaffrey. The tumor immune microenvironment in early breast cancer progression [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1583.

Contributions of Yap and Taz dysfunction to breast cancer initiation, progression, and aging-related susceptibility.

Yap and Taz are co-transcription factors that have been implicated in the development of many cancers. Here, we review the literature that analyzes the function of Yap/Taz in normal breast and breast cancer contexts. Our review of the literature suggests that that Yap and Taz are involved in breast cancer and Taz, in particular, is involved in the triple negative subtype. Nevertheless, the precise contexts in which Yap/Taz contribute to specific breast cancer phenotypes remains unclear. Indeed, Yap/Taz dysregulation acts differentially and in multiple epithelial cell types during early breast cancer progression. We propose Yap/Taz activation promotes breast cancer phenotypes in breast cancer precursor cells. Further, Yap dysregulation as a result of aging in breast tissue may result in microenvironments that increase the fitness of breast cancer precursor cells relative to the normal epithelia. <PE-FRONTEND>.

Abstract P1-05-07: microRNAs regulating tumor and immune cell interactions in the prediction of early relapse in breast cancer

Abstract Background: Metastasis remains the major lethal consequence in the progression of early breast cancer (BC). Effective immunosurveillance can inhibit metastasis, while a dysfunctional immune system can create a favorable environment for tumor spread. MicroRNAs (miRNAs) are involved in the regulation of immune response and there is evidence that they play an important role in immune escape. We investigated the effect of plasma miR-10b, miR-126, miR-19α, miR-20α and miR-155, which regulate the interaction between cancer and immune cells during immunosurveillance and immune evasion in patients with early BC. Methods: Blood samples were obtained from relapsed (n=52) and non-relapsed (n=100) patients with early BC before adjuvant chemotherapy. Plasma miRNA expression levels were assessed by qRT-PCR and expression was classified as high or low according to the median values. Receiver operating curves (ROC) were constructed to determine miRNA sensitivity and specificity. Results: miRNA expression was not correlated with patients’ characteristics or outcome. No differences in miRNA expression were observed between relapsed and non-relapsed patients. In multivariate analysis the number of infiltrated axillary lymph nodes and stage III disease independently predicted for shorter DFS (HR: 2.591; p=0.002) and OS (HR: 2.344; p=0.035), respectively. miR-126, miR-20a, miR-19a and miR-155 expression levels were lower in patients with early relapse (defined as relapse at ≤ 2 yrs; n=19) compared to those who either relapse later than 2 years (n=33) or those who remained disease-free during follow up (n=100). ROC curve analysis showed that miR-155 had the highest performance to discriminate patients with early relapse [AUC 0.825; sensitivity 90%, specificity 67% (p&amp;lt;0.001; 95% CI: 0.742-0.909)]. Multivariate analysis revealed that ER negative status and miR-155 low expression independently predicted for shorter DFS (HR: 2.616; p=0.039 and HR: 9.104; p=0.003, respectively). For the triple negative subgroup (n=31), low miR-155 expression was associated with both shorter DFS and OS (p=0.02 and p=0.032, respectively) and low miR-155 expression was an independent predictor of shorter DFS (HR: 5.056; p=0.037). Conclusions: Deregulated expression of circulating miRNAs involved in tumor and immune cell interactions evaluated before adjuvant chemotherapy is associated with early relapse in patients with primary BC. Low miR-155 expression has high accuracy in the prediction of early relapse in the whole group of patients and independently predicts for shorter DFS in the triple negative subgroup. The role of miR-155 in the pathogenesis and management of early relapse in BC merits further investigation. Citation Format: Konstantina Thomopoulou, Chara Papadaki, Alexia Monastirioti, George Koronakis, Lambros Vamvakas, Maria A Papadaki, Sofia Agelaki, Dimitrios Mavroudis. microRNAs regulating tumor and immune cell interactions in the prediction of early relapse in breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-05-07.

Abstract OT1-01-06: A pilot study utilizing a HER2 directed dendritic cell vaccine during neoadjuvant therapy of HER2+ breast cancer

Abstract Background: During the natural progression of early breast cancer, it has been demonstrated that the protective host immune response against HER2 is lost early on. Using a type 1 dendritic cell (DC1) vaccine loaded with HER2 peptides has been shown to be effective in restoring anti HER2 immune responsiveness and can lead to regression of very early non-invasive breast cancers. Prior investigations conducted by our group has suggested DC vaccines may sensitize cancers to subsequent systemic chemotherapy, and the Geparnuevo trial also suggested a prechemotherapy dosing with checkpoint therapy may improve pathologic complete response (pCR) rates in TNBC. We launched a pilot study to demonstrate safety, feasibility, and preliminary efficacy of administering the DC1 HER2 vaccine for 3 weeks prior to the initiation of neoadjuvant systemic therapy for stage II-III ER-HER2+ breast cancer. Methods: This single site study is a pilot design with a safety run in phase (n = 12) followed by an expansion cohort of 18 patients. Patients with stage II-III ER-HER2+ breast cancer who are eligible to receive neoadjuvant HER2 based chemotherapy (TCHP) can enroll. The safety run in evaluates two schedules of DC1 vaccination (ARM A = once weekly x 3 weeks and ARM B = twice weekly x 3 weeks) and will enroll six patients in each arm. After the first 3 weeks of DC1 neoadjuvant chemotherapy will be administered using standard docetaxel, carboplatin, trastuzumab, and pertuzumab given intravenously once every 3 weeks for 6 cycles. Booster vaccines will be given at weeks 25, 56, 80, and 104 and immune monitoring will be performed at these timepoints. The safety run in will evaluate safety using CTCAE 4.03 criteria along with the immunogenicity of each arm measured by ELISPOT. The arm with the best immune response at 3 weeks will be selected to proceed forward during the expansion cohort using an endpoint of pCR. Secondary endpoints will be recurrence free survival rate at 3 years and immune response. The pilot design is hypothesis generating but is likely able to detect a significant difference in pCR if the true rate is 75% assuming a historical rate of 55%. Accrual to the safety run in phase is complete and the expansion phase is underway using the twice weekly vaccination schedule. Citation Format: Hatem Soliman, Deanna Hogue, Hyo Han, Hung Khong, Ricardo Costa, Avan Armaghani, Axia Soyano Muller, Nazanin Khakpour, Marie C Lee, John Kiluk, Brian Czerniecki. A pilot study utilizing a HER2 directed dendritic cell vaccine during neoadjuvant therapy of HER2+ breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT1-01-06.

Long noncoding RNA BHLHE40-AS1 promotes early breast cancer progression through modulating IL-6/STAT3 signaling.

Ductal carcinoma in situ (DCIS) is a nonobligate precursor to invasive breast cancer. Only a small percentage of DCIS cases are predicted to progress; however, there is no method to determine which DCIS lesions will remain innocuous from those that will become invasive disease. Therefore, DCIS is treated aggressively creating a current state of overdiagnosis and overtreatment. There is a critical need to identify functional determinants of progression of DCIS to invasive ductal carcinoma (IDC). Interrogating biopsies from five patients with contiguous DCIS and IDC lesions, we have shown that expression of the long noncoding RNA BHLHE40-AS1 increases with disease progression. BHLHE40-AS1 expression supports DCIS cell proliferation, motility, and invasive potential. Mechanistically, BHLHE40-AS1 modulates interleukin (IL)-6/signal transducer and activator of transcription 3 (STAT3) activity and a proinflammatory cytokine signature, in part through interaction with interleukin enhancer-binding factor 3. These data suggest that BHLHE40-AS1 supports early breast cancer progression by engaging STAT3 signaling, creating an immune-permissive microenvironment.