Identification and Credentialing of Patient Derived Xenograft Models of Invasive Lobular Breast Carcinoma using Multi-omics and Histopathology assessment.

Breast cancer is a heterogeneous disease with numerous histological subtypes. Invasive lobular cancer (ILC) is the most common special subtype, accounting for 10-15% of all breast cancers. The pathognomonic feature of ILC is the loss of E-cadherin (CDH1), which leads to a unique single-file growth pattern of discohesive cells.

Longitudinal ctDNA Surveillance in Older Women with ER+ Breast Cancer to Facilitate Surgical De-Escalation: A Prospective, Hybrid-Decentralized Trial with Correlative Studies.

For older patients with competing comorbidities, optimizing oncologic therapies is of paramount importance. Circulating tumor DNA (ctDNA) may provide a strategy to identify which patients who may safely de-escalate certain therapies. In this prospective, hybrid-decentralized trial ( NCT05914792 ) that integrated clinical outcomes, patient- and caregiver-reported outcomes, and correlative tissue analysis, the primary objective was to determine if ctDNA levels were associated with tumor progression in older patients who opted to forgo upfront surgery in favor of primary endocrine therapy (pET).

Genomic and Immune Landscape of Pancreatic Ductal Adenocarcinoma Associated with Germline Pathogenic Variants in ATM.

Background: Germline pathogenic variants (PVs) in ATM increase the risk of pancreatic ductal adenocarcinoma (PDAC) but the underlying tumor biology of PDAC associated with germline PVs in ATM have not been adequately explored.

Experimental Design: Whole-genome (WGS), whole-exome (WES), and RNA-sequencing were performed on PDAC tumors from 25 germline ATM PVs carriers diagnosed at Mayo Clinic between 2007 and 2017. Somatic and copy number alterations, mutational signatures, transcriptomic subtypes, and the immune landscape were evaluated.

Integrating Artificial Intelligence-Driven Digital Pathology and Genomics to Establish Patient-Derived Organoids as a Novel Alternative Model for Drug Response in Head and Neck Cancer.

Patient-derived organoids (PDOs) are emerging as advanced 3D novel alternative method (NAM) preclinical models, offering significant advantages over traditional cell lines and monolayer cultures for therapeutic development. In this study, we established PDOs from surgically resected fresh tissues of human papillomavirus (HPV)-negative head and neck squamous cell carcinoma (HNSCC) across anatomical sites, tumor T-categories, and sample types. These PDOs faithfully recapitulate the tumor's pathology, mutational profile, and drug response.

p95HER2, a truncated form of the HER2 oncoprotein, drives an immunosuppressive program in HER2 breast cancer that limits trastuzumab deruxtecan efficacy.

Resistance to human epidermal growth factor receptor 2 (HER2)-targeted therapies and immuno-oncology agents poses a major challenge in treating HER2-positive breast cancer. Here we demonstrate that p95HER2, a truncated form of HER2, drives immune evasion in HER2-positive female breast cancer, enhancing tumor growth and conferring therapy resistance. This stems from the unique ability of p95HER2 to promote cancer cell-intrinsic programmed death ligand 1 expression and secretion of immunosuppressive mediators including interleukin 6.

The MBCRC Advocate Researcher Program (MARP): connecting advocates and researchers as collaborative partners in cancer research.

Involving patient advocates as partners in cancer research improves research and provides favorable experiences for both the researcher and the advocate. Previous work demonstrates challenges to establishing relationships between researchers and advocates, including uncertainty about why the relationships are necessary, how to establish them, what to say, and how they should be structured. To overcome these challenges, we established the Metastatic Breast Cancer Research Conference (MBCRC) Advocate Researcher Program (MARP) at the MBCRC in 2023.

Hope for OTHERS (Our Tissue Helping Enhance Research & Science): research results from the University of Pittsburgh rapid autopsy program for breast cancer.

Breast cancer affects 1/8 of women throughout their lifetimes, with over 90% of cancer deaths being caused by metastasis. However, metastasis poses unique challenges to research, as complex changes in the microenvironment in different metastatic sites and difficulty obtaining tissue for study hinder the ability to examine in depth the changes that occur during metastasis. Rapid autopsy programs thus fill a unique need in advancing metastasis research.

Personalized Circulating Tumor DNA Testing for Detection of Progression and Treatment Response Monitoring in Patients With Metastatic Invasive Lobular Carcinoma of the Breast.

Purpose: Despite varying treatment responses and vastly different clinicopathologic characteristics, invasive lobular carcinoma (ILC) is treated similar to other subtypes of breast cancer. Serial personalized and tumor-informed, circulating tumor DNA (ctDNA) analysis may enable real-time treatment monitoring in metastatic ILC (mILC).

Methods: In this retrospective analysis of real-world data, we analyzed ctDNA longitudinally in 66 patients with mILC using a clinically validated, personalized, tumor-informed 16-plex polymerase chain reaction-next generation sequencing assay (Signatera).

FGFR4 in endocrine resistance: overexpression and estrogen regulation without direct causative role.

Purpose: Endocrine therapy resistance is the major challenge of managing patients with estrogen receptor positive (ER+) breast cancer. We previously reported frequent overexpression of FGFR4 in endocrine-resistant cell lines and breast cancers that recurred and metastasized following endocrine therapy, suggesting FGFR4 as a potential driver of endocrine resistance. In this study, we investigated the role of FGFR4 in mediating endocrine resistance and explored the therapeutic potential of targeting FGFR4 in advanced breast cancer.

High-Throughput Empirical and Virtual Screening To Discover Novel Inhibitors of Polyploid Giant Cancer Cells in Breast Cancer.

Therapy resistance in breast cancer is increasingly attributed to polyploid giant cancer cells (PGCCs), which arise through whole genome doubling and exhibit heightened resilience to standard treatments. Characterized by enlarged nuclei and increased DNA content, these cells tend to be dormant under therapeutic stress, driving disease relapse. Despite their critical role in resistance, strategies to effectively target PGCCs are limited, largely due to the lack of high-throughput methods for assessing their viability.

CITEgeist: Cellular Indexing of Transcriptomes and Epitopes for Guided Exploration of Intrinsic Spatial Trends.

Spatial transcriptomics provides insights into tissue architecture by linking gene expression with spatial localization. Current deconvolution methods rely heavily on single-cell RNA sequencing (scRNA-seq) references, which are costly and often unavailable, mainly if the tissue under evaluation is limited, such as in a core biopsy specimen. We present a novel tool, CITEgeist, that deconvolutes spatial transcriptomics data using antibody capture from the same slide as the reference, directly leveraging cell surface protein measurements from the same tissue section.

The EstroGene2.0 database for endocrine therapy response and resistance in breast cancer.

Endocrine therapies targeting the estrogen receptor (ER/ESR1) are the cornerstone to treat ER-positive breast cancers patients, but resistance often limits their effectiveness. Notable progress has been made although the fragmented way data is reported has reduced their potential impact. Here, we introduce EstroGene2.

Breast cancer cells promote osteoclast differentiation in an MRTF-dependent paracrine manner.

Bone is a frequent site for breast cancer metastasis. The vast majority of breast cancer-associated metastasis is osteolytic in nature, and RANKL (receptor activator for nuclear factor κB)-induced differentiation of bone marrow-derived macrophages to osteoclasts (OCLs) is a key requirement for osteolytic metastatic growth of cancer cells. In this study, we demonstrate that Myocardin-related transcription factor (MRTF) in breast cancer cells plays an important role in paracrine modulation of RANKL-induced OCL differentiation.

Identification of the MRTFA/SRF pathway as a critical regulator of quiescence in cancer.

Chemoresistance is a major driver of cancer deaths. One understudied mechanism of chemoresistance is quiescence. We used single cell culture to identify, retrieve, and RNA-Seq profile primary quiescent ovarian cancer cells (qOvCa).

Cancer-cell derived S100A11 promotes macrophage recruitment in ER+ breast cancer.

Macrophages are pivotal in driving breast tumor development, progression, and resistance to treatment, particularly in estrogen receptor-positive (ER+) tumors, where they infiltrate the tumor microenvironment (TME) influenced by cancer cell-secreted factors. By analyzing single-cell RNA sequencing data from 25 ER+ tumors, we elucidated interactions between cancer cells and macrophages, correlating macrophage density with epithelial cancer cell density. We identified that S100A11, a previously unexplored factor in macrophage-cancer crosstalk, predicts high macrophage density and poor outcomes in ER+ tumors.

Hope for Others: Research Results from the University of Pittsburgh Rapid Autopsy Program for Breast Cancer.

Breast cancer affects 1/8 of women throughout their lifetimes, with over 90% of cancer deaths being caused by metastasis. However, metastasis poses unique challenges to research, as complex changes in the microenvironment in different metastatic sites and difficulty obtaining tissue for study hinder the ability to examine in depth the changes that occur during metastasis. Rapid autopsy programs thus fill a unique need in advancing metastasis research.

Mutual information for detecting multi-class biomarkers when integrating multiple bulk or single-cell transcriptomic studies.

Motivation: Biomarker detection plays a pivotal role in biomedical research. Integrating omics studies from multiple cohorts can enhance statistical power, accuracy, and robustness of the detection results. However, existing methods for horizontally combining omics studies are mostly designed for two-class scenarios (e.

Systemic and local chronic inflammation and hormone disposition promote a tumor-permissive environment for breast cancer in older women.

Unlabelled: Estrogen receptor positive (ER+) breast cancer is the most common subtype of breast cancer and is an age-related disease. The peak incidence of diagnosis occurs around age 70, even though these post-menopausal patients have low circulating levels of estradiol (E2). Despite the hormone sensitivity of age-related tumors, we have a limited understanding of the interplay between systemic and local hormones, chronic inflammation, and immune changes that contribute to the growth and development of these tumors.

ESR1 Fusions Invoke Breast Cancer Subtype-Dependent Enrichment of Ligand-Independent Oncogenic Signatures and Phenotypes.

Breast cancer is a leading cause of female mortality and despite advancements in personalized therapeutics, metastatic disease largely remains incurable due to drug resistance. The estrogen receptor (ER, ESR1) is expressed in two-thirds of all breast cancer, and under endocrine stress, somatic ESR1 mutations arise in approximately 30% of cases that result in endocrine resistance. We and others reported ESR1 fusions as a mechanism of ER-mediated endocrine resistance.

mDia2 is an important mediator of MRTF-A-dependent regulation of breast cancer cell migration.

Dysregulated actin cytoskeleton gives rise to aberrant cell motility and metastatic spread of tumor cells. This study evaluates the effect of overexpression of wild-type versus functional mutants of MRTF-A on migration and invasion of breast cancer (BC) cells. Our studies indicate that SRF's interaction is critical for MRTF-A-induced promotion of both two-dimensional and three-dimensional cell migration, while the SAP-domain function is important selectively for three-dimensional cell migration.

Spatial molecular profiling of mixed invasive ductal and lobular breast cancers reveals heterogeneity in intrinsic molecular subtypes, oncogenic signatures, and mutations.

Mixed invasive ductal and lobular carcinoma (MDLC) is a rare histologic subtype of breast cancer displaying both E-cadherin positive ductal and E-cadherin negative lobular morphologies within the same tumor, posing challenges with regard to anticipated clinical management. It remains unclear whether these distinct morphologies also have distinct biology and risk of recurrence. Our spatially resolved transcriptomic, genomic, and single-cell profiling revealed clinically significant differences between ductal and lobular tumor regions including distinct intrinsic subtype heterogeneity - e.

International survey on invasive lobular breast cancer identifies priority research questions.

There is growing awareness of the unique etiology, biology, and clinical presentation of invasive lobular breast cancer (ILC), but additional research is needed to ensure translation of findings into management and treatment guidelines. We conducted a survey with input from breast cancer physicians, laboratory-based researchers, and patients to analyze the current understanding of ILC, and identify consensus research questions. 1774 participants from 66 countries respondents self-identified as clinicians (N = 413), researchers (N = 376), and breast cancer patients and advocates (N = 1120), with some belonging to more than one category.