Citations

Abstract Invasive lobular carcinoma (ILC) accounts for 10-15% of all breast cancers, making it the most common special histological subtype of breast cancer. Initially, ILC is associated with a better response to adjuvant hormonal therapy compared to invasive ductal breast cancer (IDC). However, patients with ILC often experience a worse long-term outcome. Over 90% of ILCs are estrogen receptor positive (ER+) and do not express functional E-cadherin (CDH1). There are limited studies aimed at improved understanding of the tumor microenvironment (TME) in ILC. Therefore, we set out to generate and characterize a syngeneic mouse cell line model that mimics the genetic loss of CDH1 seen in ILC. We created an ER+ ILC-like mammary cancer model using the syngeneic SSM3 cell line, derived from an ER+ mouse mammary tumor in STAT1-deficient mice. To mimic the hallmark feature of ILC, we used CRISPR-Cas9 to knock out Cdh1. In vitro assays were performed to evaluate the effects of Cdh1 knockout (KO) in both 2D and 3D environments, focusing on cell proliferation and estrogen sensitivity. These experiments demonstrated increased growth of Cdh1 KO SSM3 cells in both 2D and 3D environments, together with altered cell morphology and increased sensitivity to estrogen.For in vivo characterization, we focused on tumor growth and metastasis. SSM3 Scr and Cdh1 KO cells were injected into the mammary fat pad of mice. Initial findings revealed increased tumor growth in mice injected with SSM3 Cdh1 KO cells, while metastasis studies are ongoing. RNA-seq analysis of both SSM3 cells grown in vitro, and in vivo tumor tissues is ongoing and will help to identify distinctive gene expression changes in the Cdh1 KO model. We will also analyze changes in the TME, such as immune cells, ECM and fibroblasts. In summary, we have successfully generated an ER+ syngeneic ILC model, and we expect that growing the cells in vitro and in vivo represents a valuable tool for studying ILC and holds promise for advancing the development of targeted immunotherapies and endocrine therapies for this breast cancer subtype. Citation Format: Insa Thale, Dixcy J. John Mary, Sarah Wang, Lora Rigatti, Jagmohan Hooda, Peter Lucas, George C. Tseng, Adrian V. Lee, Steffi Oesterreich. In vitro and in vivo characterization of Cdh1 CRISPR knockout in syngeneic ER+ SSM3 mouse mammary tumor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3925.

Abstract Recent studies have described the tumor microenvironment and the key transcription factors in untreated small cell lung cancer (SCLC), but less is known about the salient features in recurrent SCLC (rSCLC). This information could provide valuable insight about the effectiveness of second and later line therapies. In this study, we compared transcriptome profiles (by RNA-seq) of rSCLC against untreated primaries (pSCLC). rSCLC samples (n=23) were obtained from frozen biopsies in patients enrolled in our MC1923 (NCT04607954) phase 2 clinical trial whose disease progressed after chemoimmunotherapy. The pSCLC group (n=73) included publicly available data from fresh frozen primary tumors after surgical resections. Normalized expression data were used in immune deconvolution and gene set enrichment analysis (GSEA) in molecular signature database. Additional GSEA included gene sets describing ASCL1 (A), NEUROD1 (N), ASCL1 and NEUROD1 (AN), and POU2F3 (P) transcription factor activities which are used for subtyping of SCLC. Immune deconvolutions by multiple software algorithms suggested depletion of immune infiltrates in rSCLC compared with pSCLC including dendritic cells, B cells, CD8+ T cells, and M1 macrophages. Furthermore, we found decreased chemotaxis and increased apoptosis of dendritic cells, reduced TNF signaling, and reduced lymphocyte co-stimulation in rSCLC by GSEA. Additionally, in comparisons with pSCLC, rSCLC tumors had significantly lower enrichment scores for POU2F3 activity, representing the SCLC-P subtype (p < 0.007). Importantly, the SCLC-P was recently reported to be more immune inflamed than the other A, N, and AN subtypes. Altogether, our analyses provide strong evidence that the tumor microenvironment of rSCLC is significantly more immunosuppressed and with reduced immune cell infiltrates compared to pSCLC. Developing therapeutic strategies aimed at “warming” the tumor microenvironment and enhancing anti-tumor immune activity in ongoing multimodal therapies of recurrent SCLC will likely provide significant benefits to patients. Citation Format: Farhad Kosari, Mohamed Ali, Sarah H. Johnson, Alex Adjei, Julian R. Molina, Aaron S. Mansfield, Anastasios Dimou, Kaushal Parikh, Mohamed Shanshal, Katherine E. Smith, Ailsa G. Luce, Anna J. Schwecke, Janet Lensing, Ying-Chun Lo, John C. Cheville, George Vasmatzis, Konstantinos Leventakos. Small cell lung cancer (SCLC) at recurrence has a “colder” tumor microenvironment than primary SCLC according to gene expression profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6614.

Abstract Breast cancer affects 1 in 8 women and often results from mutations caused by oxidative DNA damage from reactive oxygen species. Two key lesions, 8-hydroxy-adenine (8-OH-Ade) and 4, 6-diamino-5-formamidopyrimidine (FAPY-Ade), exhibit two distinct patterns: FAPY-Ade lesions are predominant in normal tissues, while 8-OH-Ade lesions are abundant in cancerous tissues. These shifts reflect tissue redox status, which may provide a pathway to assess future breast cancer risk. Quantitation of these lesions by chemical detection methods is precise but time-intensive and impractical for high-throughput clinical applications. To address this, monoclonal antibodies have been developed and offer a rapid, scalable, and clinically practical alternative for efficiently detecting and quantifying these biomarkers. This innovation can potentially support personalized breast cancer screening strategies. BALB/c mice were immunized with 8-OH-Ade or FAPY-Ade haptens coupled to Keyhole Limpet Hemocyanin (KLH). After three monthly immunizations, the serums of IgG and IgM titers were evaluated. The mice having the highest IgG titer for each antigen were given an intravenous boost, and the spleens were removed three days later for fusions according to standard methods. Using hapten-conjugated BSA-coated 96-well Pro-Bind plates, the ELISA results demonstrated 30-40 positive wells for each antigen. Up to ten positive wells for each antigen were selected and cloned to yield monoclonal antibody-producing hybridomas. The ELISA of the anti-FAPY-Ade antibody, FA5, showed concentration-dependent reduced binding to immobilized BSA-FAPY-Ade hapten conjugate in increasing FAPY-Ade, confirming its FAPY-Ade binding specificity. Immunohistochemistry using normal and cancerous breast tissue revealed significant staining of normal breast tissue compared to cancerous breast tissue using the FA5 antibody. Conversely, the anti-8-OH-Ade antibody, 8A6, displayed weak staining of normal breast tissue with higher staining of cancerous breast tissues. The results demonstrate that monoclonal antibodies specific for 8-OH-Ade and a novel antibody specific for the ring-opening reactive oxygen product, FAPY-Ade, are practical and rapid alternatives to chemical detection methods for their analysis. Immunohistochemistry mirrored past results using chemical detection methods for these oxidized bases, with high FAPY-Ade compared to 8-OH-Ade in normal tissues and the opposite result in cancer-derived tissues. The potential for high-throughput analysis of 8-OH-Ade and FAPY-Ade levels in the DNA of breast tissues may provide information on future breast cancer risk. Further research is underway to evaluate this hypothesis. Citation Format: Zenzeale A. Hudson, Sarah McLaughlin, Alfredo A. Paredes, Gary K. Ostrander, Eric H. Holmes. Monoclonal antibody evaluation of oxidative DNA base damage in normal and neoplastic breast tissues: development of antibodies specific for 8-OH-adenine and 4, 6-diamino-5-formamidopyrimidine (FAPY-adenine) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7063.

Abstract HER2+ breast cancer is an aggressive subtype of cancer that often develops resistance to the current first-line therapy, Trastuzumab. In our previous work, we demonstrated that HER2 signaling activates mitochondrial creatine kinase 1 (MtCK1), which enhances mitochondrial energy metabolism for rapid proliferation of breast cancer cells. However, pharmacological blockage of MtCK1 with a creatine analog, Cyclo-Creatine (CCr), requires millimolar concentration to inhibit breast cancer cell proliferation and is associated with brain toxicity, limiting its clinical application. This brain toxicity may result from the inhibition of the creatine transporter SLC6A8 by CCr, which decreases to transport creatine into brain. In this study, we took a prodrug development approach to identify and optimize protection groups for CCr, designed to bypass the SLC6A8 transporter, enhancing bioavailability and reducing toxicity. Liquid chromatography-mass spectrometry (LC-MS) was utilized to analyze drug uptake and creatine metabolites in cells treated with the prodrugs. Prodrug C, which is our lead prodrug candidate, demonstrated a seven-fold increase in cellular uptake and more than a hundred-fold improvement in cell-killing effects as compared to CCr in an MtCK1 specific manner in breast cancer cells. This approach offers a promising therapeutic strategy to inhibit HER2+ breast cancer cell by disrupting mitochondrial energy metabolism. Future investigations will focus on validating this prodrug’s pharmacokinetics (PK) and pharmacodynamics (PD) through further preclinical studies. Citation Format: Ya Li, Yetong Huang, Puja Dey, Sadae Hitosugi, Sarah A. Buhrow, Joel M. Reid, Taro Hitosugi. Prodrug development of Cyclo-Creatine: Enhancing permeability and reducing toxicity for HER2+ breast cancer treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4157.

Abstract Introduction: Monitoring minimal residual disease (MRD) is critical in multiple myeloma (MM) to predict outcomes and guide therapy. Traditional bone marrow (BM) aspirates for MRD detection are invasive and limited by sample quality. We therefore explored cell-free DNA (cfDNA) fragmentation as a less invasive alternative for MRD detection. Methods: We performed 30-40X whole-genome sequencing (WGS) on peripheral blood cfDNA from 45 MM patients, collecting baseline (n = 45) and follow-up samples (n = 98) from eight Canadian sites (M4 and IMMAGINE studies) and one U.S. site (SPORE study), plus 25 healthy controls. Samples were collected post-induction therapy (n = 13), 100 days post-autologous stem cell transplantation (ACST, n = 36), and during maintenance therapy (n = 49). Multiparameter flow cytometry (MFC) MRD testing was conducted on 77 samples. We evaluated insert size metrics and MM-specific chromatin accessibility (from Ordoñez et al., 2020) using Griffin (described in Doebley et al., 2022). Results: Baseline samples had a higher proportion of short fragments (20-150 bp) than follow-up samples (p = 0.0037) and healthy controls (p = 0.019). A fragment score (FS) based on weighted fragment distribution (per Vessies et al., 2022) was highest at baseline (mean = -0.384), followed by MRD-positive (mean = -0.495) and MRD-negative (mean = -0.550) samples. MRD-negative FS was lower than baseline samples (p < 0.001) but higher than healthy controls (mean = -0.639; p = 0.016). Baseline samples had lower coverage at MM-specific chromatin regions than MRD timepoints (p < 0.05; baseline mean = 0.982; MRD-positive = 0.989; MRD-negative = 0.994; healthy = 0.993), suggesting higher transcriptional activity pre-treatment. MRD-negative samples had higher coverage than MRD-positive cases (p < 0.01). Using logistic regression, we assessed the predictive performance of FS and coverage at MM-specific sites. FS alone achieved an AUC of 0.632 (sensitivity [SN] 39.4%, specificity [SP] 92.1%, accuracy [AC] 67.6%). Coverage yielded an AUC of 0.681 (SN 75.8%, SP 60.5%, AC 67.6%). Combining FS and coverage at MM sites improved performance (AUC = 0.734; SN 48.5%, SP 92.1%, AC 71.8%). We next evaluated whether adjusting the BM tumor cell percentage cutoff by MFC could improve performance. At 0.017% (1 in 5, 789 cells) for MRD positivity, the combined model’s accuracy reached 83% with an AUC of 0.757 (SN 17%, SP 97%). Conclusions: cfDNA fragmentomic analysis achieved high specificity (92-97%) in detecting MRD, providing a less invasive alternative to facilitate serial monitoring. While sensitivity remains an area for improvement, the high specificity of cfDNA makes it valuable for confirming MRD negativity and reducing invasive procedures. Future efforts aim to enhance sensitivity by integrating additional fragmentomic features. Citation Format: Dor D. Abelman, Jenna Eagles, Aimee Wong, Saumil Shah, Stephanie Pedersen, Stephenie Prokopec, David S. Scott, Sarah Bridges, Darrell White, Irwindeep Sandhu, Kevin Song, Esteban Braggio, Alli Murugesan, Anthony Reiman, Suzanne Trudel, Trevor J. Pugh. Tumor-independent monitoring of minimal residual disease in multiple myeloma using cfDNA fragmentomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3250.

This case series examines long-term outcomes for 2 aquaporin-4-IgG (AQP4-IgG)–positive patients with neuromyelitis optica spectrum disorder (NMOSD) who underwent autologous hematopoietic stem cell transplantation with a nonmyeloablative conditioning regimen and rituximab.

Objective: We aimed to analyze the current literature for IORT in gynecological cancers and summarized clinical outcomes regarding patient selection. Methods: A systematic search was conducted utilizing PUBMED, Embase, and CINAHL to identify studies following PRISMA-ScR guidelines. A PICOS structure was utilized: population: patients with epithelial gynecological cancers; intervention: IORT; C: a comparator was not required, as we aimed to analyze patient selection; outcome: clinical outcomes and overall survival; and S: experimental and quasi-experimental analytical observational studies and descriptive observational studies, excluding case series published in English and limited to the last 10 years. Data extraction was conducted for patient selection, IORT, oncological outcomes, and morbidity. Results: A total of 707 results were identified, and 509 studies were uploaded to Covidence for screening after removing duplications. Of the 21 eligible studies, 9 were included in the final review. The total number of patients included was 348. The studies were retrospective single-institution studies, except for one. There was significant heterogeneity in their design and protocols. IORT was exclusively used for recurrent and advanced stage gynecological cancers adjunct to pelvic exenteration or laterally extended endopelvic resections with variable indications across institutions. The mean number of IORT patients per study was 2.8 per year. Survival rates were variable and dependent on the surgical margin. Endometrial cancer had a favorable outcome compared to vulvar and cervical cancers. Conclusions: Current clinical practice, as demonstrated by the research, is consistent with NCCN guidelines that endorse the application of IORT in instances of recurrent cervical, vaginal, and vulvar malignancies; however, there are no established recommendations for primary tumors. The analysis shows that there are gaps in our knowledge, mainly regarding the status of the margins, the criteria used to choose patients, and the outcomes that are specific to each histology. The standardization of protocols and prospectively powered studies are needed to refine patient selection criteria.

Abstract Objective This QI project aimed to enhance pediatric intensive care unit (PICU) staff’s ability to recognize and compassionately respond to caregiver fatigue (CF), tailoring interventions to the specific needs identified. Methods An interdisciplinary team of healthcare professionals developed and implemented a comprehensive strategy to improve the recognition and management of CF. This QI project included creating educational materials for staff, enhancing unit resources, and introducing targeted interventions. Data collection involved pre- and post-project surveys. Results The program led to significant improvements in PICU staff’s confidence in recognizing and responding to CF, increased availability of unit resources, enhanced staff compassion, and reduced callousness toward others. Conclusions This QI project emphasized the role that structured initiatives and interdisciplinary collaboration can play in addressing CF within the PICU setting. Improvements in staff confidence, compassion, and reduced burnout demonstrate the program’s effectiveness. These findings underscore the value of targeted interventions and provide a valuable framework for further research and can serve as a model for other healthcare units seeking to integrate CF management into comprehensive patient care.

Background Pineal parenchymal tumor of intermediate differentiation (PPTID) is a rare tumor. This study aims to evaluate patient outcomes and propose a treatment algorithm based on existing literature and our case series. Methods This prospective observational study includes seven patients diagnosed with PPTID through histopathology. We analyzed their clinical presentation, magnetic resonance imaging findings, surgical approaches, histopathological and immunohistochemical analysis, adjuvant treatments, and outcomes. We conducted univariate and multivariate statistical analyses. Results The mean patient age was 40 years, with a male predominance. All patients presented with hydrocephalus, four of which required cerebrospinal fluid diversion procedures. The average tumor size was 3.13cm, with 85.7% showing brain invasion. Surgical outcomes included one gross total resection, two near total resections, and four subtotal resections. The supracerebellar infratentorial (Krause) approach was used in 71.4% of cases. About 85.7% were diagnosed with grade 3 PPTID. Five patients received adjuvant radiotherapy. The analysis showed each additional mitosis unit decreased survival by 0.17 units, equating to roughly 2 months (P < 0.016). Follow-up ranged from 6 to 120 months, with a 5-year survival rate of 57.1%. Factors influencing survival included the extent of tumor resection, brain invasion, tumor grade, and adjuvant treatment, although it was not statistically significant due to the small sample size. Conclusion We propose a treatment algorithm for PPTID and highlight the importance of further research to understand its biological characteristics. Safe maximal resection appears beneficial for higher-grade PPTID, but the role of adjuvant treatment after complete resection of lower-grade tumors remains uncertain.