Citations

Abstract Introduction: Patients with ER+/HER2- breast cancer associated with germline pathogenic variants (PVs) in BRCA1, BRCA2 and CHEK2 exhibit distinct clinicopathological features compared to sporadic cases. However, the optimal endocrine therapy strategies for these patients remain undefined. The Breast Cancer Index (BCI) is a validated gene expression-based signature that stratifies patients based on the risk of overall (0-10 years) and late (post-5 years) distant recurrence and predicts the likelihood of benefit from extended endocrine therapy (EET) in early-stage, HR+ breast cancer. Here we utilize BCI to investigate endocrine sensitivity and the predicted EET benefit in a cohort of ER+/HER2- breast cancer patients with BRCA1, BRCA2 and CHEK2 PVs. Methods: BRCA1, BRCA2 and CHEK2 PV carriers with ER+/HER2- breast cancer diagnosed at Mayo Clinic between 1996 and 2024 at Mayo Clinic were identified from a registry tracking germline test result. For comparison, we utilized the BCI Registry, a prospective, multi-institutional tumor registry of patients with early-stage ER+/HER2- breast cancer undergoing BCI testing, regardless of germline PV status. The analysis was restricted to women with invasive, early-stage locoregional breast cancer and available pre-treatment tumor specimens. BCI testing was performed by RT-PCR blinded to clinical outcome. BCI prognostic and BCI predictive categories were compared between the Mayo Clinic germline PV cohort and the BCI Registry using descriptive statistics and Fisher’s exact test. Results: The final analysis included 123 PVcarriers (BRCA1: 36; BRCA2: 40; CHEK2: 47) from the MayoClinic cohort and 2,563 women from the BCI Registry. The proportion of patientsdiagnosed before age 50 was higher among PV carriers—52.8% in BRCA1,50.0% in BRCA2, and 21.3% in CHEK2—compared to 7.0% in the BCIRegistry. PV carriers were also more likely to be premenopausal andnode-positive at diagnosis. Based on BCI score, a significant higher proportionof BRCA1 (75.0%, p=0.002) andBRCA2 (70.0%, p=0.01) PV carriers wereclassified as high risk, compared to 48.5% of patients in the BCI Registry, butno significant difference was seen for CHEK2 PV carriers (46.8%,p=0.88). A significantly higher proportion of BRCA1 PV carriers werepredicted to benefit from EET compared to the BCI Registry cohort (77.8% vs.33.9%, p<0.001), whereas no significant differences in BCI Predictivecategories were observed for BRCA2 or CHEK2 PV carriers. Overall,compared to breast cancer cases in the BCI registry, a significant differencein the distribution of the combined BCI prognostic and predictive categorieswas noted for BRCA1 (p<0.001)and BRCA2 (p=0.02) PV carriers,but not for CHEK2 PV carriers (p=0.66). In particular, BRCA1 andBRCA2 PV carriers were enriched for high-risk tumors with a high likelihoodof EET benefit (66.7% and 37.5%, respectively vs 25.1%, p<0.001 and p=0.02),whereas only a small non-significant increase was observed for CHEK2 PVcarriers (29.8% vs 25.1%, p=0.66) compared to breast cancer cases in the BCIRegistry. Conclusions: Genomicclassification by BCI reveals distinct patterns of endocrine sensitivity andpredicted EET benefit among germline PV carriers, particularly in BRCA1and BRCA2 PV carriers. These findings warrant further investigation andmay inform personalized endocrine therapy strategies for women with germlinePV-associated ER+/HER2- breast cancer. Citation Format: S. Yadav, B. O'Neal, S. Yasir, N. Siuliukina, A. Karki, Y. Zhang, A. K. Anderson, K. Treuner, M. P. Goetz, F. J. Couch. Endocrine Sensitivity and Predicted Benefit of Extended Endocrine Therapy based on Breast Cancer Index (BCI) in BRCA1, BRCA2 and CHEK2 Pathogenic Variant Carriers with ER+/HER2- Breast Cancer [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS2-08-25.

Abstract Background: Stromal tumor infiltrating lymphocytes (sTILs) are associated with improved response to chemotherapy and better overall survival (OS) in triple-negative breast cancer (TNBC). Quantification of sTILs via hematoxylin and eosin (H&E) tumor slides offers a widely available method to define a simple, effective surrogate for host anti-tumor immunity. Digitization of H&E slides has rapidly gained acceptance for use in diagnostic pathology and research, opening the door for image-based computational approaches to enumerate sTILs, among other features. Methods: We describe QuTILs - a multilayer perceptron-based framework to detect/enumerate TILs trained on >700,000 cells via The Cancer Genome Atlas Program (TCGA) slide images, implemented in the widely used open-source QuPath digital pathology suite. QuTILs was applied to digital H&E images using standard computing in primary breast tumors from phase 3 breast cancer clinical trials - CALGB 40502 (testing), CALGB 40601 and 40603 (validation) - in total 1,729 total images from 962 unique patients. The aims of this investigation were: 1) to assess the relationship between TIL patterns with overall or event-free survival outcomes; 2) to benchmark diverse image-based characteristics of TIL abundance and spatial architecture; and 3) to evaluate the association between image-based TIL levels and RNA-seq-based immune deconvolution metrics (CIBERSORT, EPIC, quanTIseq). Results: QuTILs average processing time was 7.9 minutes for whole-slide total TIL count and area density on a standard laptop workstation. In CALGB 40502, there was positive but modest correlation between pathologist TILs and QuTILs total TILs %, higher in the TNBC subgroup of CALGB 40502 (Pearson r = 0.55). In Cox proportional hazards models, the CALGB 40502 TNBC cohort showed significant univariate association for total TILs % with increasing decile (higher total TIL%) associated with reduced hazard (hazard ratio [HR]: 0.712, 95% CI: 0.559-0.906; P = 0.006), which remained significant in multivariable model incorporating age, race, and treatment arm (HR: 0.713, 95% CI: 0.556-0.915; P = 0.008). In validation TNBC clinical trial CALGB 40603, marginal TILs % was significant in the univariable Cox model (HR: 0.786, 95% CI: 0.639-0.966). Evaluation of TILs % by QuTILs with RNAseq-based deconvolution metrics in cohort-stratified and deconvolution method-stratified multivariable models showed that decile total TILs % by QuTILs was shown to significantly predict outcome in the EPIC (HR: 0.668, 95% CI: 0.466-0.957) and quanTIseq (HR: 0.646, 95% CI: 0.446-0.936) sets, with a similar magnitude as in clinical Cox, suggesting that RNA-based deconvolution estimates may not supplement the prognostic power of image-based TIL estimates. Exploratory analyses of pre- versus post-neoadjuvant therapy H&E images in CALGB 40603 and CALGB 40601 revealed a significant decrease in QuTILs total TIL% in CALGB 40603 for all pairs (n = 118 pairs, pre-median=9.52%, post-median=6.33%; Wilcoxon signed rank P < 0.001) but no significant change in QuTILs total TIL% among all pairs in CALGB 40601 (n = 82 pairs, pre-median=15.92%, post-median=15.10%; P = 0.886). Conclusions: QuTILs provides a computationally efficient open-source workflow for sTIL identification from digital H&E images that can be deployed on a standard laptop. We present the first evaluation of digital sTIL enumeration in CALGB 40502, CALGB 40603, and CALGB 40601 phase III breast cancer clinical trials and demonstrate significant prognostic association with QuTIL total TIL % among TNBCs across studies. Citation Format: M. Vater, R. Salgado, E. Blige, H. Lefebvre, A. Strahan, M. Gatti-Mays, H. Rugo, K. Ballman, M. Watson, Y. Wen, R. Leon-Ferre, K. Niazi, W. Symmans, L. Carey, K. AbdulJabbar, Z. Li, D. Stover. Qutils: open-source image-based infiltrating immune cell detection and outcomes in calgb 40502, calgb 40603, and calgb 40601 phase iii breast cancer clinical trials [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS2-07-27.

Abstract Primary hyperparathyroidism is most commonly caused by a single parathyroid adenoma. Multiple and ectopic adenomas are less common and can present diagnostic challenges. We present the case of a 57-year-old woman with hypercalcemia, hypercalciuria, and inappropriately normal parathyroid hormone (PTH) levels. Sestamibi scan did not demonstrate abnormal uptake; however, contrast-enhanced 4-dimensional computed tomography imaging reported 2 candidate lesions described as tubular shaped structures located posterior to the inferior pole of each thyroid lobe. Surgical exploration was performed and the surgical pathology reported hypercellular parathyroid tissue resected from the left inferior thyroid bed and benign thymic tissue with embedded hypercellular parathyroid tissue resected from the right inferior thyroid bed. Postoperative calcium levels normalized, and the patient remained eucalcemic at 1-year follow-up. This case underscores the importance of embryologic understanding and thorough surgical exploration in patients with biochemically confirmed primary hyperparathyroidism and inconclusive imaging.

Abstract Background While immune checkpoint inhibitors (ICIs) provide durable clinical benefit in a subset of patients, current biomarkers to predict response lack accuracy. Ex vivo cytokine profiling has shown promise for improved accuracy but has been mostly limited to ICIs targeting PD-1 [Voabil et al, 2021]. This poses the question of whether ICIs beyond αPD-1 – such as CTLA4 blockade, which has been reported to act within the draining lymph node – would be amenable to similar approaches. The Elephas platform characterizes response to ICIs in live tumor fragments (LTFs) from core needle biopsies (CNBs) and resections using longitudinal cytokine profiling. Using a panel of 7 clinically relevant ICI regimens, we demonstrate cytokine responses across diverse tumor types, characterize similarities and differences in cytokine response profiles across different ICIs, and explore specimen variability in responses across ICI treatments. Methods CNBs were collected through 3 observational clinical trials (NCT05478538, NCT05520099, NCT0634962) and a biobank collection study, while resections were procured from NCI CHTN. LTFs were generated using an automated cutting device and encapsulated in hydrogel. LTFs were treated with mono (αPD-1, αPD-L1, αCTLA4, αLAG-3) or combination therapy (αPD-1/αCTLA4, αPD-1/αLAG-3, αPD-L1/αCTLA4) using a sequential treatment strategy in which isotype control followed by ICI were added to the same tissue in a single well. This approach enabled the comparison of control and treatment conditions while mitigating the effects of tumor heterogeneity. Production rates for 46 cytokines were measured using a multiplex assay. Remaining T-cell reactivity was also evaluated at the end of the assay to better understand the presence of functional T cells in LTFs. Results Unsupervised hierarchical clustering of cytokine profiling data from CNB LTFs across 129 patients identified defined responder and non-responder clusters. Within the response cluster, 4 subclusters with distinct immune phenotypes were identified. While tight clustering of samples treated with the same ICI was not observed, some enrichment of samples treated with combination ICIs was observed within individual subclusters. Further, cytokine responses to αCTLA4 monotherapy were observed, suggesting that CTLA4 blockade may act beyond the draining lymph node. LTFs from resections enabled the characterization of cytokine response profiles across treatment conditions within individual specimens, including the magnitude of cytokine response and variability in cytokine response profiles. Evaluation of T-cell reactivity provided further insight into the presence of functional T-cells in LTFs and the extent of T-cell activation achieved by ICI treatment. Conclusions This study demonstrates the platform’s ability to recapitulate diverse mechanisms of immune activation ex vivo, enabling the characterization of cytokine responses to clinically relevant ICI mono or combination therapy in live tumor tissue and supporting future efforts to improve ICI response prediction beyond αPD-1. Citation Format: Pichet Adstamongkonkul, Pierre Cunin, Santanu Bhattacharya, Tanmay Kulkarni, Amreen Nasreen, Nathan Marhefke, Nina Chen, T S. Ramasubramanian, Laura Hrycyniak, Julie Zweng, Erika von Euw, Christina Vivelo, Sean Caenepeel, Debabrata Mukhopadhyay, Hinco Gierman, Hilario Ramos. Characterization of αPD1, αPD-L1, αCTLA4, and αLAG3 as mono and combination therapy in live tumor fragments using an ex vivo cytokine profiling platform [abstract]. In: Proceedings of the AACR Immuno-Oncology Conference (AACR IO): Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2026 Feb 18-21; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2026;14(2 Suppl):Abstract nr B032.

Abstract Background: Clear cell renal cell carcinoma (ccRCC), metastatic castration-resistant prostate cancer (mCRPC), and glioblastoma (GBM) are highly treatment-refractory tumors characterized by elevated TGF-β1, a key suppressor of antitumor immunity and antigen presentation. Because CAR-T cells infiltrating these tumors experience persistent physiologic TGF-β exposure, assessing CAR-T functional resilience across increasing TGF-β concentrations is critical for determining therapeutic feasibility. Methylseleninic acid (MSA), a pharmacologic selenium compound, potently inhibits TGF-β1, PD-L1, and VEGF with minimal off-target toxicity. FN14, the TWEAK receptor and a metastasis driver, is selectively overexpressed in these malignancies, making it a high-specificity CAR target. Methods: We developed second-generation anti-FN14 CARs containing CD28 or 4-1BB costimulatory domains and a CD3ζ signaling motif, then lentivirally transduced into primary human CD4+ and CD8+ T cells. Cytotoxicity against FN14+ ccRCC, mCRPC, GBM lines and patient-derived cells was assessed using LDH release and xCELLigence assays. Effector function was evaluated through intracellular cytokine profiling, multiplex analysis, and phenotypic characterization by flow cytometry. CAR-T persistence in TGF-β-rich conditions was measured using CCK-8 proliferation assays, and Ki-67 and activation/exhaustion markers (PD-1, CXCR3) in the presence of 0-10 ng/mL TGF-β. MSA’s immunomodulatory and synergistic effects were tested at physiologically concentrations to measure impacts on CAR-T viability, metabolic activity, cytokine secretion, and tumor cell susceptibility. Results: Anti-FN14 CAR-T cells mediated rapid, antigen-specific lysis across all tumor types, achieving >50% specific killing at a 1:1 E:T ratio. MSA (2.5-5 µM) reduced tumor PD-L1 and TGF-β expression by >40% and enhanced CAR-T metabolic activity, IL-2, and IFN-γ secretion. CAR-T cells maintained comparable proliferation and activation in 0-5 ng/mL TGF-β, indicating that antigen-driven signaling counteracted low-to-moderate TGF-β-mediated suppression. Ex vivo CAR-T manufacturing with MSA (2.5 µM) improved cytotoxicity and persistence versus untreated CAR-T cells (p < 0.01). MSA’s effects were dose- and schedule-dependent and remained within human-relevant exposure ranges without detectable toxicity. Conclusion: MSA enhances anti-FN14 CAR-T cytotoxicity, metabolic fitness, and sustained effector activity by suppressing tumor-derived TGF-β1 and PD-L1 and by directly improving CAR-T functional capacity. Consistent with this mechanism, physiological TGF-β levels (0-5 ng/mL) did not significantly impair CAR-T proliferation or activation, demonstrating intrinsic resilience of FN14 CAR-T cells in TGF-β-rich environments. As a clinically relevant TGF-β1 inhibitor and active metabolite of seleno-L-methionine, MSA represents a readily translatable strategy to reduce CAR-T exhaustion and enhance efficacy in TGF-β-rich solid tumors including ccRCC, mCRPC, and GBM. Citation Format: Obed B. Amissah, Casey Ager, Yousef Zakharia, Youcef M. Rustum, Gloria B. Kim. Anti-FN14 CAR-T cells overcome TGF-β-mediated suppression, and their synergy with methylseleninic acid enhances cytotoxicity and effector function in kidney, prostate, and brain tumors [abstract]. In: Proceedings of the AACR Immuno-Oncology Conference (AACR IO): Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2026 Feb 18-21; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2026;14(2 Suppl):Abstract nr C010.

Abstract Endometriosis (EMS) is an estrogen-dependent, chronic inflammatory disease in which endometrial-like tissue grows outside the uterus, leading to pelvic pain, dysmenorrhea, dyspareunia, and infertility. Increasing evidence shows that these symptoms do not arise from the presence of ectopic tissue alone. Rather, they reflect a sustained neuroimmune process in which inflammatory, neural, and stromal pathways continuously interact. Within the peritoneal cavity of EMS, immune activation elevates cytokines such as IL-1β, IL-6, and TNF-α, which stimulate production of neurotrophic mediators including NGF, BDNF, and IGF-1. These signals induce sensory-nerve sprouting, lower nociceptor thresholds, and convert lesions into hyperinnervated, pain-generating structures. Once these fibers infiltrate lesions, they release neuropeptides such as substance P (SP) and calcitonin gene-related peptide (CGRP). Rather than simply transmitting nociceptive signals, these neurons actively reshape the lesion microenvironment. SP and CGRP amplify inflammation, promote immune-cell recruitment, and drive epithelial–mesenchymal transition and myofibroblast differentiation, accelerating the fibrotic remodeling characteristic of deep infiltrating endometriosis. This neuropeptide-driven activity strengthens the lesion’s neuroimmune profile and forms a feed-forward loop in which inflammation, nerve growth, and fibrosis reinforce one another over time. Persistent nociceptive input from sensitized lesions produces downstream changes in the central nervous system. Within the spinal cord, activated microglia and astrocytes release proinflammatory mediators that enhance excitatory signaling and diminish inhibitory tone. With continued input, spinal and cortical circuits undergo neuroplastic changes that give rise to central sensitization, hyperalgesia, allodynia, and the cross-organ sensitization that links pain across the uterus, bladder, bowel, and pelvic floor. These long-range effects explain why pain may persist even when visible lesions are small or surgically removed. Together, these findings position endometriosis as a chronic systemic neuroimmune disorder maintained by reciprocal signaling between immune cells, sensory neurons, and central pain networks. Viewing EMS through this lens highlights multiple therapeutic entry points. Targeting NGF–TrkA and CGRP–RAMP1 signaling, modulating macrophage and B-cell function, dampening glial activation, or applying neuromodulatory techniques offers a more rational pathway to interrupt the self-reinforcing neuroimmune loop that sustains pain. Integrating immunologic and neurobiologic evidence therefore provides a foundation for mechanism-based therapies capable of delivering more durable relief and improving long-term quality of life. Citation Format: Ariana F. Rahman. Endometriosis as a Neuroimmune Disorder: Integrating Inflammation, Innervation, and Sensitization [abstract]. In: Proceedings of the AACR Immuno-Oncology Conference (AACR IO): Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2026 Feb 18-21; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2026;14(2 Suppl):Abstract nr A062.

Background: Postoperative emergency department (ED) utilization significantly reduces patient satisfaction and increases health care spending. Purpose: To identify the incidence, risk factors, and reasons for ED visits within 90 days of Achilles tendon repair (ATR). Study Design: Case-control study; Level of evidence, 3 Methods: This study utilized the PearlDiver database to identify all instances of primary ATR. Patient age, sex, Elixhauser comorbidity index (ECI), region, and insurance coverage were extracted. The incidence, timing, and primary diagnoses for those with an ED visit 90 days post-ATR were extracted. Also, the 90-day total cost was determined and compared for those with and without a postoperative ED visit. Welch t test and Pearson chi-square test were used to determine significant differences between groups. Multivariable logistic regressions were used to determine risk factors associated with ED utilization after ATR. Results: Of the 82,604 patients with an ATR identified in the database, 6939 (8.4%) had ≥1 ED visit. Of ED visits, 1506 (21.7%) occurred in the first week after ATR and 3587 (51.7%) occurred in the first 4 weeks after ATR. The mean 90-day cost for those with an ED visit was significantly greater than those without an ED visit ($7330 ± $13,383 vs $3515 ± $5787; P < .001). Independent risk factors associated with ED utilization within 90 days were younger age (odds ratio [OR], 1.02; P < .001), female sex (OR, 1.26; P < .001), higher ECI (OR, 1.17; P < .001), a history of tobacco use (OR, 1.57; P < .001), and having Medicaid insurance (OR, 1.73; P < .001). Most ED visits within the first 2 weeks after ATR were for surgical-site pain (53.6%), with 62.4% of diagnoses being directly related to the surgical site. After 2 weeks following ATR, pain persisted as the most common reason for ED utilization (20.9%). Conclusion: More than 8% of patients had ≥1 ED visit within 90 days of ATR, with over half occurring in the first 4 weeks. This markedly increased health care spending. Addressing regional disparities, improving Medicaid acceptance policies, and enhancing perioperative care plans, such as multimodal pain management and addressing the psychological aspects of pain, may reduce the incidence and economic burden of postoperative ED visits.

Abstract Response Assessment in Pediatric Neuro-Oncology (RAPNO) is an international working group dedicated to developing standardized recommendations for response assessment in children with central nervous system tumors enrolled on clinical trials. This standardization facilitates easier and more reliable comparison of responses across trials. Since the first RAPNO publication in 2013, response guidelines have been issued for medulloblastoma (MB), low-grade glioma (LGG), high-grade glioma (HGG), diffuse intrinsic pontine glioma, ependymoma, and craniopharyngioma. Many of these guidelines have already been incorporated into clinical trials to evaluate their effectiveness and accuracy. RAPNO has always been predicated on the idea that these consensus recommendations will require updates over time as they are applied in practice given technological advancements, evolving treatment approaches, and growing knowledge of disease pathology. A half-day RAPNO symposium sponsored by the Society of Neuro-Oncology was held in San Diego, California, United States, on May 15, 2025. This event coincided with the 8th Biennial Pediatric Society of Neuro-Oncology meeting. The main objectives were to identify ongoing RAPNO challenges, discuss potential updates, and plan future initiatives across 3 specific groups: (1) LGG/Craniopharyngioma, (2) HGG/diffuse midline glioma (DMG)/Ependymoma, and (3) MB and other seeding tumors. This manuscript reviews the symposium proceedings and highlights key topics and challenges discussed, as well as outlining future RAPNO initiatives.