Metastatic Breast Research Articles

Microbiome-Stealth Regulator of Breast Homeostasis and Cancer Metastasis.

Cumulative evidence attests to the essential roles of commensal microbes in the physiology of hosts. Although the microbiome has been a major research subject since the time of Luis Pasteur and William Russell over 140 years ago, recent findings that certain intracellular bacteria contribute to the pathophysiology of healthy vs. diseased tissues have brought the field of the microbiome to a new era of investigation. Particularly, in the field of breast cancer research, breast-tumor-resident bacteria are now deemed to be essential players in tumor initiation and progression. This is a resurrection of Russel's bacterial cause of cancer theory, which was in fact abandoned over 100 years ago. This review will introduce some of the recent findings that exemplify the roles of breast-tumor-resident microbes in breast carcinogenesis and metastasis and provide mechanistic explanations for these phenomena. Such information would be able to justify the utility of breast-tumor-resident microbes as biomarkers for disease progression and therapeutic targets.

Sulfamoylated Estradiol Analogs Targeting the Actin and Microtubule Cytoskeletons Demonstrate Anti-Cancer Properties In Vitro and In Ovo.

The microtubule-disrupting agent 2-methoxyestradiol (2-ME) displays anti-tumor and anti-angiogenic properties, but its clinical development is halted due to poor pharmacokinetics. We therefore designed two 2-ME analogs in silico-an ESE-15-one and an ESE-16 one-with improved pharmacological properties. We investigated the effects of these compounds on the cytoskeleton in vitro, and their anti-angiogenic and anti-metastatic properties in ovo. Time-lapse fluorescent microscopy revealed that sub-lethal doses of the compounds disrupted microtubule dynamics. Phalloidin fluorescent staining of treated cervical (HeLa), metastatic breast (MDA-MB-231) cancer, and human umbilical vein endothelial cells (HUVECs) displayed thickened, stabilized actin stress fibers after 2 h, which rearranged into a peripheral radial pattern by 24 h. Cofilin phosphorylation and phosphorylated ezrin/radixin/moesin complexes appeared to regulate this actin response. These signaling pathways overlap with anti-angiogenic, extra-cellular communication and adhesion pathways. Sub-lethal concentrations of the compounds retarded both cellular migration and invasion. Anti-angiogenic and extra-cellular matrix signaling was evident with TIMP2 and P-VEGF receptor-2 upregulation. ESE-15-one and ESE-16 exhibited anti-tumor and anti-metastatic properties in vivo, using the chick chorioallantoic membrane assay. In conclusion, the sulfamoylated 2-ME analogs displayed promising anti-tumor, anti-metastatic, and anti-angiogenic properties. Future studies will assess the compounds for myeloproliferative effects, as seen in clinical applications of other drugs in this class.

Neuronal substance P drives metastasis through an extracellular RNA-TLR7 axis.

Tumour innervation is associated with worse patient outcomes in multiple cancers1,2, which suggests that it may regulate metastasis. Here we observed that highly metastatic mouse mammary tumours acquired more innervation than did less-metastatic tumours. This enhanced innervation was driven by expression of the axon-guidance molecule SLIT2 in tumour vasculature. Breast cancer cells induced spontaneous calcium activity in sensory neurons and elicited release of the neuropeptide substance P (SP). Using three-dimensional co-cultures and in vivo models, we found that neuronal SP promoted breast tumour growth, invasion and metastasis. Moreover, patient tumours with elevated SP exhibited enhanced lymph node metastatic spread. SP acted on tumoral tachykinin receptors (TACR1) to drive death of a small population of TACR1high cancer cells. Single-stranded RNAs (ssRNAs) released from dying cells acted on neighbouring tumoural Toll-like receptor 7 (TLR7) to non-canonically activate a prometastatic gene expression program. This SP- and ssRNA-induced Tlr7 gene expression signature was associated with reduced breast cancer survival outcomes. Therapeutic targeting of this neuro-cancer axis with the TACR1 antagonist aprepitant, an approved anti-nausea drug, suppressed breast cancer growth and metastasis in multiple models. Our findings reveal that tumour-induced hyperactivation of sensory neurons regulates multiple aspects of metastatic progression in breast cancer through a therapeutically targetable neuropeptide/extracellular ssRNA sensing axis.

Elucidating the Intricate Roles of Gut and Breast Microbiomes in Breast Cancer Metastasis to the Bone.

Breast cancer is the most predominant and heterogeneous cancer in women. Moreover, breast cancer has a high prevalence to metastasize to distant organs, such as the brain, lungs, and bones. Patients with breast cancer metastasis to the bones have poor overall and relapse-free survival. Moreover, treatment using chemotherapy and immunotherapy is ineffective in preventing or reducing cancer metastasis. Microorganisms residing in the gut and breast, termed as the resident microbiome, have a significant influence on the formation and progression of breast cancer. Recent studies have identified some microorganisms that induce breast cancer metastasis to the bone. These organisms utilize multiple mechanisms, including induction of epithelial-mesenchymal transition, steroid hormone metabolism, immune modification, bone remodeling, and secretion of microbial products that alter tumor microenvironment, and enhance propensity of breast cancer cells to metastasize. However, their involvement makes these microorganisms suitable as novel therapeutic targets. Thus, studies are underway to prevent and reduce breast cancer metastasis to distant organs, including the bone, using chemotherapeutic or immunotherapeutic drugs, along with probiotics, antibiotics or fecal microbiota transplantation. The present review describes association of gut and breast microbiomes with bone metastases. We have elaborated on the mechanisms utilized by breast and gut microbiomes that induce breast cancer metastasis, especially to the bone. The review also highlights the current treatment options that may target both the microbiomes for preventing or reducing breast cancer metastases. Finally, we have specified the necessity of maintaining a diverse gut microbiome to prevent dysbiosis, which otherwise may induce breast carcinogenesis and metastasis especially to the bone. The review may facilitate more detailed investigations of the causal associations between these microbiomes and bone metastases. Moreover, the potential treatment options described in the review may promote discussions and research on the modes to improve survival of patients with breast cancer by targeting the gut and breast microbiomes.

Unusual metastases to the breast from different extramammary malignancies: a multimodality imaging approach in a case series.

Extramammary metastases are uncommon and usually related to a poor prognosis, but the radiologist can suspect the diagnosis based on the patient's clinical history and specific imaging findings. Several imaging procedures may be used to evaluate breast metastases from different extramammary malignancies, including mammography, ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography-CT (PET-CT). The clinical and imaging presentation of these metastases is contingent upon how the illness spreads, however, they have the potential to resemble either benign or malignant breast tumors. Metastases that disseminate hematologically tend to appear as a single round or oval mass with circumscribed margins. Sonographically, they are usually hypoechoic, and with CT or MRI, they usually enhance. Lymphatic dissemination, for example, frequently reveals significant asymmetry with skin thickening and diffuse breast edema, which is compatible with an inflammatory breast carcinoma. Knowing the many types of cancers that have the potential to spread to the breast as well as being able to accurately diagnose them is crucial to prevent a needless mastectomy and provide guidance for subsequent treatment. The purpose of this article is to provide a better understanding of the imaging features and immunohistochemistry (IHC) of secondary tumors of the breast by presenting eight distinctive cases, which will enable radiologists to recognize this entity.

CCN6 Suppresses Metaplastic Breast Carcinoma by Antagonizing Wnt/β-Catenin Signaling to Inhibit EZH2-Driven EMT.

Metaplastic breast carcinomas (mBrCA) are a highly aggressive subtype of triple-negative breast cancer with histologic evidence of epithelial-to-mesenchymal transition and aberrant differentiation. Inactivation of the tumor suppressor gene cellular communication network factor 6 (CCN6; also known as Wnt1-induced secreted protein 3) is a feature of mBrCAs, and mice with conditional inactivation of Ccn6 in mammary epithelium (Ccn6-KO) develop spindle mBrCAs with epithelial-to-mesenchymal transition. Elucidation of the precise mechanistic details of how CCN6 acts as a tumor suppressor in mBrCA could help identify improved treatment strategies. In this study, we showed that CCN6 interacts with the Wnt receptor FZD8 and coreceptor LRP6 on mBrCA cells to antagonize Wnt-induced activation of β-catenin/TCF-mediated transcription. The histone methyltransferase EZH2 was identified as a β-catenin/TCF transcriptional target in Ccn6-KO mBrCA cells. Inhibiting Wnt/β-catenin/TCF signaling in Ccn6-KO mBrCA cells led to reduced EZH2 expression, decreased histone H3 lysine 27 trimethylation, and deregulation of specific target genes. Pharmacologic inhibition of EZH2 reduced growth and metastasis of Ccn6-KO mBrCA mammary tumors in vivo. Low CCN6 is significantly associated with activated β-catenin and high EZH2 in human spindle mBrCAs compared with other subtypes. Collectively, these findings establish CCN6 as a key negative regulator of a β-catenin/TCF/EZH2 axis and highlight the inhibition of β-catenin or EZH2 as a potential therapeutic approach for patients with spindle mBrCAs. Significance: CCN6 deficiency drives metaplastic breast carcinoma growth and metastasis by increasing Wnt/β-catenin activation to upregulate EZH2, identifying EZH2 inhibition as a mechanistically guided treatment strategy for this deadly form of breast cancer.

A Multi-Center, Multi-Parametric MRI Dataset of Primary and Secondary Brain Tumors

Brain metastases (BMs) and high-grade gliomas (HGGs) are the most common and aggressive types of malignant brain tumors in adults, with often poor prognosis and short survival. As their clinical symptoms and image appearances on conventional magnetic resonance imaging (MRI) can be astonishingly similar, their accurate differentiation based solely on clinical and radiological information can be very challenging, particularly for “cancer of unknown primary”, where no systemic malignancy is known or found. Non-invasive multiparametric MRI and radiomics offer the potential to identify these distinct biological properties, aiding in the characterization and differentiation of HGGs and BMs. However, there is a scarcity of publicly available multi-origin brain tumor imaging data for tumor characterization. In this paper, we introduce a multi-center, multi-origin brain tumor MRI (MOTUM) imaging dataset obtained from 67 patients: 29 with high-grade gliomas, 20 with lung metastases, 10 with breast metastases, 2 with gastric metastasis, 4 with ovarian metastasis, and 2 with melanoma metastasis. This dataset includes anonymized DICOM files alongside processed FLAIR, T1-weighted, contrast-enhanced T1-weighted, T2-weighted sequences images, segmentation masks of two tumor regions, and clinical data. Our data-sharing initiative is to support the benchmarking of automated tumor segmentation, multi-modal machine learning, and disease differentiation of multi-origin brain tumors in a multi-center setting.

Immune mediated support of metastasis: Implication for bone invasion.

Bone is a common organ affected by metastasis in various advanced cancers, including lung, breast, prostate, colorectal, and melanoma. Once a patient is diagnosed with bone metastasis, the patient's quality of life and overall survival are significantly reduced owing to a wide range of morbidities and the increasing difficulty of treatment. Many studies have shown that bone metastasis is closely related to bone microenvironment, especially bone immune microenvironment. However, the effects of various immune cells in the bone microenvironment on bone metastasis remain unclear. Here, we described the changes in various immune cells during bone metastasis and discussed their related mechanisms. Osteoblasts, adipocytes, and other non-immune cells closely related to bone metastasis were also included. This review also summarized the existing treatment methods and potential therapeutic targets, and provided insights for future studies of cancer bone metastasis.

VHL suppresses UBE3B-mediated breast tumor growth and metastasis

Protein homeostasis is predominantly governed through post-translational modification (PTM). UBE3B, identified as an oncoprotein, exhibits elevated protein levels in breast cancer. However, the impact of PTM on UBE3B remains unexplored. In this study, we show that VHL is a bona fide E3 ligase for UBE3B. Mechanistically, VHL directly binds to UBE3B, facilitating its lysine 48 (K48)-linked polyubiquitination at K286 and K427 in a prolyl hydroxylase (PHD)-independent manner. Consequently, this promotes the proteasomal degradation of UBE3B. The K286/427R mutation of UBE3B dramatically abolishes the inhibitory effect of VHL on breast tumor growth and lung metastasis. Additionally, the protein levels of UBE3B and VHL exhibit a negative correlation in breast cancer tissues. These findings delineate an important layer of UBE3B regulation by VHL.

Obesity Induces Temporally Regulated Alterations in the Extracellular Matrix That Drive Breast Tumor Invasion and Metastasis.

Obesity is associated with increased incidence and metastasis of triple-negative breast cancer, an aggressive breast cancer subtype. The extracellular matrix (ECM) is a major component of the tumor microenvironment that drives metastasis. To characterize the temporal effects of age and high-fat diet (HFD)-driven weight gain on the ECM, we injected allograft tumor cells at 4-week intervals into mammary fat pads of mice fed a control or HFD, assessing tumor growth and metastasis and evaluating the ECM composition of the mammary fat pads, lungs, and livers. Tumor growth was increased in obese mice after 12 weeks on HFD. Liver metastasis increased in obese mice only at 4 weeks, and elevated body weight correlated with increased metastasis to the lungs but not the liver. Whole decellularized ECM coupled with proteomics indicated that early stages of obesity were sufficient to induce changes in the ECM composition. Obesity led to an increased abundance of the proinvasive ECM proteins collagen IV and collagen VI in the mammary glands and enhanced the invasive capacity of cancer cells. Cells of stromal vascular fraction and adipose stem and progenitor cells were primarily responsible for secreting collagen IV and collagen VI, not adipocytes. Longer exposure to HFD increased the invasive potential of ECM isolated from the lungs and liver, with significant changes in ECM composition found in the liver with short-term HFD exposure. Together, these data suggest that changes in the breast, lungs, and liver ECM underlie some of the effects of obesity on triple-negative breast cancer incidence and metastasis. Significance: Organ-specific extracellular matrix changes in the primary tumor and metastatic microenvironment are mechanisms by which obesity contributes to breast cancer progression.

MicroRNA-1205 promotes breast cancer cell metastasis by regulating epithelial-to-mesenchymal transition via targeting of CDK3

Metastasis poses a huge obstacle to the survival of breast cancer patients. The microRNA miR-1205 acts as a tumor suppressor in various cancers, but its roles in breast cancer and metastasis remain unclear. To elucidate its function in breast cancer progression, we analyzed miR-1205 expression in human tumor samples and carried out a series of functional studies in in vitro and in vivo. miR-1205 was expressed more highly in metastatic breast tumor samples than in non-metastatic samples and was associated with lymph node metastasis, clinical stage, and poor prognosis. Moreover, miR-1205 promoted breast cancer cell invasiveness in vitro and metastasis in mice by directly targeting CDK3 and reducing CDK3 protein levels. We also showed that CDK3 interacts with Snail protein, inducing Snail degradation via the ubiquitin-proteasome system and potentially affecting epithelial-to-mesenchymal transition. Furthermore, analysis of clinical tissue samples indicated that CDK3 and miR-1205 levels were inversely correlated in lymph node metastasis-positive primary tumors. This study demonstrated the pro-metastatic role of miR-1205 in breast cancer, mediated via a novel miR-1205/CDK3/Snail axis. Moreover, we identified miR-1205 and CDK3 as potential markers of invasion and progression in breast cancer.

Multi-cancer early detection (MCED) test performance in cancer survivors.

1628 Background: Cancer survivors (CS) are at risk for recurrent or new primary tumors in any organ, but there is lack of clear guidance and options for long-term surveillance. We analyzed the performance of a blood-based MCED test that detects cancer-specific methylation patterns and predicts cancer signal origin (CSO) in CS in the PATHFINDER study (PF; NCT04241796). Methods: PF enrolled6662 participants (pts) ≥50 yr without clinical suspicion of cancer; 6578 samples were analyzed with a refined MCED test. Pts were stratified by CS status (treated cancer >3 yr prior to study vs no prior cancer); in CS, prior cancer type and time from diagnosis were recorded. Cancers diagnosed during PF were classified as recurrent or new primaries. Positive predictive value (PPV), number needed to screen (NNTS), and CSO accuracy were assessed. Results: CS comprised 25% (1609/6578) of pts analyzed; 73% were female. Median age was 66 yr; age at prior diagnosis was 8% <40, 22% 40-49, 70% ≥50 yr. Most common prior cancers were breast (749, 47%), melanoma (163, 10%) and prostate (141, 9%). A higher proportion of pts with cancer diagnosis was observed in CS vs those with no prior cancer (Table). Among 20 CS with cancer signal detected, 10 cancers were diagnosed in 9 pts; 5 recurrent (all metastatic breast) and 5 new primaries (uterine stage 1 [found as incidental lesion on imaging during MCED-triggered workup for recurrent breast cancer], sarcoma stage 2, ovarian stage 3, lymphoma and CRC stage 4). During 1-yr follow-up in those with negative MCED result, new cancer diagnoses in CS included 13 recurrences (all local) and 15 new primaries. Of the 13 new primaries with known stage, 46% were stage 1 (2 breast, 1 melanoma, 1 thyroid, 1 lymphoma, 1 lung), 31% stage 2 (2 lymphomas, 1 melanoma, 1 breast), 15% stage 3 (1 pancreas, 1 pleural mesothelioma), and 7% stage 4 (1 prostate). Yield, PPV, NNTS, and CSO accuracy were similar in CS and no prior cancer group. Years between MCED cancer detection and prior cancer in CS was 4-11 for recurrent and 8-15 for new primaries. Most (4/5) new primaries were cancers with no USPSTF-recommended screenings. Conclusions: The MCED test detected both cancer recurrences and new primaries in CS for whom multiple years had elapsed since their original diagnosis, potentially expanding surveillance options for this patient group. Cancers in CS not detected by MCED were predominantly early stage. Test performance was similar in those with and without a cancer history. Clinical trial information: NCT04241796 . [Table: see text]

Discovery of potent CSK inhibitors through integrated virtual screening and molecular dynamic simulation.

Oncogenic overexpression or activation of C-terminal Src kinase (CSK) has been shown to play an important role in triple-negative breast cancer (TNBC) progression, including tumor initiation, growth, metastasis, drug resistance. This revelation has pivoted the focus toward CSK as a potential target for novel treatments. However, until now, there are few inhibitors designed to target the CSK protein. Responding to this, our research has implemented a comprehensive virtual screening protocol. By integrating energy-based screening methods with AI-driven scoring functions, such as Attentive FP, and employing rigorous rescoring methods like Glide docking and molecular mechanics generalized Born surface area (MM/GBSA), we have systematically sought out inhibitors of CSK. This approach led to the discovery of a compound with a potent CSK inhibitory activity, reflected by an IC50 value of 1.6 nM under a homogeneous time-resolved fluorescence (HTRF) bioassay. Subsequently, molecule 2 exhibits strong growth inhibition of MD anderson - metastatic breast (MDA-MB) -231, Hs578T, and SUM159 cells, showing a level of growth inhibition comparable to that observed with dasatinib. Treatment with molecule 2 also induced significant G1 phase accumulation and cell apoptosis. Furthermore, we have explored the explicit binding interactions of the compound with CSK using molecular dynamics simulations, providing valuable insights into its mechanism of action.

Breaking the Tumor Chronic Inflammation Balance with a Programmable Release and Multi-Stimulation Engineering Scaffold for Potent Immunotherapy.

Tumor-associated chronic inflammation severely restricts the efficacy of immunotherapy in cold tumors. Here, a programmable release hydrogel-based engineering scaffold with multi-stimulation and reactive oxygen species (ROS)-response (PHOENIX) is demonstrated to break the chronic inflammatory balance in cold tumors to induce potent immunity. PHOENIX can undergo programmable release of resiquimod and anti-OX40 under ROS. Resiquimod is first released, leading to antigen-presenting cell maturation and the transformation of myeloid-derived suppressor cells and M2 macrophages into an antitumor immune phenotype. Subsequently, anti-OX40 is transported into the tumor microenvironment, leading to effector T-cell activation and inhibition of Treg function. PHOENIX consequently breaks the chronic inflammation in the tumor microenvironment and leads to a potent immune response. In mice bearing subcutaneous triple-negative breast cancer and metastasis models, PHOENIX effectively inhibited 80% and 60% of tumor growth, respectively. Moreover, PHOENIX protected 100% of the mice against TNBC tumor rechallenge by electing a robust long-term antigen-specific immune response. An excellent inhibition and prolonged survival in PHOENIX-treated mice with colorectal cancer and melanoma is also observed. This work presents a potent therapeutic scaffold to improve immunotherapy efficiency, representing a generalizable and facile regimen for cold tumors.

Point-of-care Ultrasound Diagnosed Intraocular Breast Metastasis.

A 60-year-old female presented to the emergency department with unilateral eye pain and vision loss. Point-of-care ultrasound (POCUS) was performed, which demonstrated ocular metastatic lesions of breast cancer. Ocular metastasis is rare, clinically challenging, and may present with a wide range of ophthalmic symptoms. However, POCUS may safely and rapidly identify metastatic lesions to direct further care.

Therapeutic Potential of Withaferin-A and Propolis Combinational Drug Therapy for Breast Cancer: An In Vivo Interpretation for Validating the Antiproliferative Efficacy and Ameliorative Potential in Benzo[a]pyrene-Induced Breast Metastasis

Therapeutic Potential of Withaferin-A and Propolis Combinational Drug Therapy for Breast Cancer: An In Vivo Interpretation for Validating the Antiproliferative Efficacy and Ameliorative Potential in Benzo[a]pyrene-Induced Breast Metastasis

Correction: Cost-effectiveness of talazoparib for patients with locally advanced or metastasized breast cancer in Germany

Correction: Cost-effectiveness of talazoparib for patients with locally advanced or metastasized breast cancer in Germany

The cellular localization and oncogenic or tumor suppressive effects of angiomiotin-like protein 2 in tumor and normal cells.

Angiomiotin (AMOT) family comprises three members: AMOT, AMOT-like protein 1 (AMOTL1), and AMOT-like protein 2 (AMOTL2). AMOTL2 is widely expressed in endothelial cells, epithelial cells, and various cancer cells. Specifically, AMOTL2 predominantly localizes in the cytoplasm and nucleus in human normal cells, whereas associates with cell-cell junctions and actin cytoskeleton in non-human cells, and locates at cell junctions or within the recycling endosomes in cancer cells. AMOTL2 is implicated in regulation of tube formation, cell polarity, and shape, although the specific impact on tumorigenesis remains to be conclusively determined. It has been shown that AMOTL2 enhances tumor growth and metastasis in pancreatic, breast, and colon cancer, however inhibits cell proliferation and migration in lung, hepatocellular cancer, and glioblastoma. In addition to its role in cell shape and cytoskeletal dynamics through co-localization with F-actin, AMOTL2 modulates the transcription of Yes-associated protein (YAP) by binding to it, thereby affecting its phosphorylation and cellular sequestration. Furthermore, the stability and cellular localization of AMOTL2, influenced by its phosphorylation and ubiquitination mediated by specific proteins, affects its cellular function. Additionally, we observe that AMOTL2 is predominantly downregulated in some tumors, but significantly elevated in colorectal adenocarcinoma (COAD). Moreover, overall analysis, GSEA and ROC curve analysis indicate that AMOTL2 exerts as an oncogenic protein in COAD by modulating Wnt pathway, participating in synthesis of collagen formation, and interacting with extracellular matrix receptor. In addition, AMOTL2 potentially regulates the distribution of immune cells infiltration in COAD. In summary, AMOTL2 probably functions as an oncogene in COAD. Consequently, further in-depth mechanistic research is required to elucidate the precise roles of AMOTL2 in various cancers.

Abstract PO4-07-11: FDG-PET is superior to bone scintigraphy for the detection of bone metastases in breast cancer patients

Abstract Background: Bone is the commonest site for metastases in breast cancer patients, with up to 44% of patients having bone as their sole site of metastatic disease. Patients are at increased risk of morbidity from skeletal related events (SRE) from bone metastases due to pathological fractures and spinal cord compression. Early diagnosis is crucial so that bone modifying agents can be used to prevent SREs and other agents such as CDK4/6 inhibitors can be considered. Bone scintigraphy is the most widely performed first investigation for patients at high risk or symptomatic from bone metastases. Methods: We performed a meta-analysis comparing FDG-PET and bone scintigraphy using PubMed, Science Direct, and Embase for the literature search. 1009 patients were included in the study. Data for 2 × 2 contigency tables was selected and QUADAS-2 was used for quality assessment. Diagnostic accuracy was performed using Graph pad Prism 9.5.1 and R studio 2022. Pooled sensitivity and specificity of FDG-PET/CT was 96.6% (95% CI=91.5%-98.7%) and 96.8% (95% CI=82.1%-99.5%) respectively. Respective results for BS were 88.3% (95% CI=79.8%-93.5%) and 81.3% (95% CI=63.1%-91.7%). Sensitivity and specificity of FDG-PET/CT was significantly higher than BS (P=0.0063, P= 0.0068, respectively). The diagnostic odds ratio and area under ROC curve were significantly higher for FDG-PET/CT than BS (654.36 vs 35.24, and 0.980 vs 0.877, respectively). Conclusion: FDG-PET is superior to bone scinitigaphy for the detection of bone metastases in breast cancer.The benefits of replacing BS with FDG-PET/CT are evident. However othere technologies such as DW-MRI should be considered. Large multicentre prospective trials with strict FDG-PET/CT imaging protocols compared to DW-MRI both for disease detection and monitoring of response are required to strengthen the evidence in this field, to help inform imaging guidelines and best practices in the future. Newer technologies such as [18F]estradiol (FES)-PET and [18F]GE-226 for HER2 expression also warrant further investigation in ER positive and HER2 positive breast cancer. Citation Format: Laura Kenny, Maisher Tin-U. FDG-PET is superior to bone scintigraphy for the detection of bone metastases in breast cancer patients [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 PO4-07-11.

Abstract PO5-18-06: On-going phase 1A clinical trial of A01, a chimerized monoclonal antibody to Progranulin/Glycoprotein 88 (GP88) in patients with advanced malignancy

Abstract Progranulin (PGRN/GP88) is an 88 kDa glycoprotein characterized by seven and a half double cysteine rich repeats which is the largest member of the granulin-epithelin protein family. PGRN/GP88 has been demonstrated as a biological driver of tumorigenesis, survival, and drug resistance in several cancers including breast cancer (BC), lung prostate, ovarian and digestive cancers. PGRN/GP88 tissue expression is an independent prognostic factor of recurrence in breast, lung cancers while elevated serum PGRN/GP88 level in metastatic breast, lung, ovarian and prostate cancer patients. Elevated PGRN/GP88 levels are associated with poor outcomes such as progression and shortened survival. An anti-human PGRN/GP88 monoclonal antibody able to inhibit the the in vitro and in vivo action of human PGRN/GP88 has been developed, chimerized and expressed in CHO cells. All IND enabling activities including pharmacology, GMP manufacturing, formulation and GLP toxicology studies have been conducted. The IND application has been filed and cleared by the Food and Drug Administration. A first-in-human, first-in-class phase 1 safety and efficacy clinical study of AG01 in patients with solid tumors and advanced disease with special focus on patients with breast, lung and ovarian cancers has been initiated and is on-going at the University of Maryland Greenebaum Cancer Center. The trial is registered as NCT05627960 to clinicaltrials.gov site. The presentation will provide an update on the number of patients enrolled in this on-going phase 1A trial. Supported by grants R44CA162629 and R44CA224718 from the National Cancer Institute to GS. Citation Format: Katherine Tkaczuk, Paula Rosenblatt, Ranee Mehra, Katherine Scilla, Nancy Tait, Binbin Yue, Ginette Serrero. On-going phase 1A clinical trial of A01, a chimerized monoclonal antibody to Progranulin/Glycoprotein 88 (GP88) in patients with advanced malignancy [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 PO5-18-06.