Citations

Morel-Lavallee lesions (MLLs) are traumatic closed degloving injuries with operative intervention (OI), especially excisional debridement, remaining the mainstay of treatment. However, high-quality evidence describing operative techniques and outcomes remains limited. This study aimed to characterize current OI practices and associated outcomes, especially among patients undergoing excisional debridement, hypothesizing an increased risk of wound complications with this approach for MLLs. Methods This prospective (2021-2024), multicenter, observational study was conducted across 15 trauma centers and included patients diagnosed with MLL who underwent OI. The association between operative technique (eg, excisional debridement) and the primary outcome of wound complications was evaluated. Wound complications were defined as cellulitis, deep wound infection, skin necrosis, necrotizing soft tissue infection (NSTI), and/or organized hematoma. Results Of 88 MLL patients undergoing OI, 36 (40.9%) had excisional debridement, with 4 (11.1%) limited excision to skin, 20 (55.6%) extended to subcutaneous tissue, and 12 (33.3%) down to muscle. Excisional debridement had higher rates of skin necrosis (22.2% vs. 1.9%, P = .002). Although overall rates of wound complications were statistically similar between cohorts (33.3% vs. 17.3%, P = .098), univariate analysis demonstrated excisional debridement had increased risk of wound complications (OR 2.52, CI 1.07-5.97, P = .035). Conclusion This prospective multicenter study over three years demonstrated that a fifth of MLLs undergoing excisional debridement developed postoperative skin necrosis. Excisional debridement also had a more than two-fold increased risk of wound complications compared to other OIs. These findings underscore the importance of investigating alternative operative techniques, such as incision and drainage or minimally invasive debridement methods.

Abstract Background Recently, a posterior pathway for fluid drainage from the retina to the meningeal lymphatics in the optic nerve (ON) sheath was identified in rodents using intravitreal imaging tracers directly injected into the ocular-globe. Fluid and solute clearance along this pathway may be associated with many diseases. However, intravitreal tracers are rarely used in clinical imaging. As intravenous Gadolinium-based-contrast-agent (GBCA) can enter the globe via the blood-ocular-barriers, it may provide an alternative approach to image this pathway. Purpose To establish a clinically feasible intravenous GBCA-based MRI approach for tracking fluid and solute transport along the posterior lymphatic pathway in the ocular glymphatic system. Materials&Methods This prospective study was conducted from March 2021 to September 2022 in healthy participants. Dynamic-susceptibility-contrast-in-the-CSF (cDSC) MRI was performed before, immediately and 4 hours after intravenous-GBCA administration to track GBCA distribution in aqueous humor (AH) and cerebrospinal fluid (CSF) in regions-of-interest (ROIs) in the globe (anterior-cavity, vitreous-body), in the intraorbital and extraorbital ON, and in the intracranial CSF space proximal to the ON (chiasmatic-cistern, interpeduncular-cistern). Kruskal–Wallis tests with post-hoc Dunn’s tests were used for group comparisons. Results Sixteen healthy participants (mean age±SD: 51±21 years, 5 men) were recruited. Intravenous-GBCA enhancement was observed in all ROIs immediately after injection. At 4-hour-post-GBCA, the vitreous body showed a trend of smaller enhancement area (55±11% versus 49±11%, P =.14) and lower GBCA-concentration (0.044±0.014 versus 0.028±0.010 mmol/L, P =.07) compared to immediate-post-GBCA. The intraorbital ON showed more widespread enhancement (39±5% versus 59±6%, P =.01) and significantly higher GBCA-concentration (0.023±0.009 versus 0.059±0.015 mmol/L, P <.001) at 4-hour-post-GBCA. Conclusion Dynamic fluid and solute transportation along the posterior lymphatic pathway in the ocular glymphatic system in healthy participants was measured by tracking intravenous-GBCAs entering the globe via the blood-ocular-barriers using cDSC-MRI. Summary Statement Dynamic fluid and solute transportation along the posterior lymphatic pathway in the ocular glymphatic system in healthy participants was measured by tracking intravenous-Gadolinium-based-contrast-agents entering ocular-globe via blood-ocular-barriers using dynamic-susceptibility-contrast-in-the-CSF (cDSC)-MRI. Key Results In this prospective study of sixteen participants, Gadolinium-based-contrast-agent (GBCA)-induced signal changes were detected in the aqueous-humor and cerebrospinal fluid immediately following intravenous administration using dynamic-susceptibility-contrast-in-the-CSF (cDSC)-MRI. At 4-hour-post-GBCA, the vitreous-body showed a trend of smaller enhancement area (55±11% versus 49±11%, P =.14) and lower GBCA-concentration (0.044±0.014 versus 0.028±0.010 mmol/L, P =.07) compared to immediate-post-GBCA. The intraorbital-optic-nerve showed more widespread enhancement (39±5% versus 59±6%, P =.01) and higher GBCA-concentration (0.023±0.009 versus 0.059±0.015 mmol/L, P <.001) at 4-hour-post-GBCA.

Management of locoregionally advanced human papillomavirus-positive oropharyngeal squamous cell carcinoma (HPV(+) OPSCC) can include induction chemotherapy followed by definitive chemoradiation. The standard induction regimen of cisplatin, docetaxel, and 5-fluorouracil (TPF) is associated with high toxicity. Given the chemosensitivity of HPV(+) OPSCC, platinum doublets are frequently used as induction therapy with potentially less toxicity. This retrospective study aimed to compare outcomes between treatment-naive HPV(+) OPSCC patients receiving induction TPF and those receiving an induction platinum doublet. Data collected included tumor characteristics, response after chemoradiation, hospitalization rates, and overall survival (OS). Fifty-five patients (18 TPF and 37 platinum doublet) were included. There was no significant difference in response after completion of definitive chemoradiation (TPF: CR 83.3%, PR 5.6%, progression or metastasis 11.1% vs. platinum doublet: CR 75.7%, PR 16.2%, progression or metastasis 8.1%; p = 0.5241). There were also no differences in hospitalizations for adverse events (38.9% in TPF vs. 40.5% in platinum doublet, p = 0.907) or recurrence (11.1% in TPF vs. 2.7% in platinum doublet, p = 0.198). The 5-year OS was 84.6% in the TPF group and 81.5% in the platinum doublet group (p = 0.581). Induction platinum doublet regimens offer comparable OS, response, and hospitalization rates to TPF in locally advanced HPV(+) OPSCC. Induction with a platinum doublet may be a viable de-escalation strategy for patients who are not candidates for TPF.

Abstract Background: Up to 50% of patients with breast cancer experience chemotherapy-inducednausea (CIN) and 95% experience fatigue. A comprehensive understanding of biological mechanisms remains elusive. Herein, we evaluated the association of CIN and fatigue with clinical and multi-omics features, including serum and stool metabolites before (T1) to after chemotherapy (T2). Methods: Patients with breast cancer (n=36) who were to receive chemotherapy, provided symptom assessment using the Memorial Symptom Assessment Scale, stool and blood samples at T1 and T2. Patients provided dietary intake data using a Dietary Screener Questionnaire at T1. Descriptive and univariate analyses evaluated associations of co-occurringsymptoms and diet with CIN and fatigue at T2. Gut microbiome was sequenced using shotgun metagenomics. Targeted metabolomics was performed on stool and serum. Shift in the abundance of taxonomic groups and metabolite levels from T1 to T2 were evaluated in association with CIN and fatigue. Results: Approximately 64% of the patients experienced CIN and 94% experienced fatigue atT2. Three gastrointestinal symptoms co-occurred with CIN and fatigue. Higher daily average intake of calcium (p=0.013) and dairy (p=0.035) were associated with CIN. Levels of hexosylceramides, ceramide, phosphatidylcholine and sphingomyelins were significantly perturbed in association with CIN and fatigue (p&lt;0.05). Conclusion: CIN and fatigue are associated with perturbation in the sphingolipid turnover pathway, which negatively impacts functions in the gut-liver axis that include apoptosis activity and change in bile acid levels. Confirmatory studies are warranted to support the development of interventions to alleviate CIN and fatigue in patients with breast cancer receiving chemotherapy.Keywords: breast cancer; chemotherapy-induced nausea; fatigue; metabolites; sphingolipids Citation Format: Komal Preet Singh, Brenda J. Ernst, Jun Chen, Surendra Dasari, Felipe Batalini, Cindy Tofthagen, Kathryn J. Ruddy, Keenan Pituch, Linda Chlan. Perturbations in gut liver axis functions are associated with chemotherapy induced nausea and fatigue in patients with breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6309.

Background Immune exclusion inhibits antitumor immunity and response to immunotherapy, but its mechanisms remain poorly defined. In triple-negative breast cancer (TNBC), an aggressive and generally immune-rich subtype, an immune-cold microenvironment predicts poor prognosis due to a limited response to chemotherapy and immune checkpoint inhibitors. This study aimed to identify mechanisms regulating immune infiltration in TNBC. Methods We performed spatial transcriptomic analysis comparing immune-enriched versus immune-cold treatment-naïve TNBCs. Functional analyses, including loss-of-function and reconstitution experiments, were conducted to investigate the role of trophoblast cell-surface antigen 2 (TROP2), a key target of anticancer antibody drug conjugates (ADCs), in promoting TNBC progression. A humanized TROP2 syngeneic TNBC model was used to assess the effects of TROP2-targeting in combination with anti-programmed cell death protein 1 (PD-1) therapy. Additionally, data from patients treated with immune checkpoint blockade were used to test hypotheses from the preclinical findings. Results We reveal that TROP2 controls barrier-mediated immune exclusion in TNBC through claudin 7 association and tight junction regulation. TROP2 expression is inversely correlated with T-cell infiltration and predicts poor outcomes in TNBC. We demonstrate that TROP2 is sufficient to drive tumor progression in vivo in a CD8 T cell-dependent manner, while its loss deregulates expression and localization of multiple tight junction proteins, enabling T-cell infiltration. We show that TROP2 targeting via hRS7, the antibody component of the ADC sacituzumab govitecan, enhances the anti-PD-1 response and improves T-cell accessibility and effector function. Correspondingly, TROP2 expression is highly associated with lack of response to anti-PD-1 therapy in human breast cancer. Conclusions This study defines a new mechanism of barrier-mediated immune exclusion in cancer controlled by TROP2-dependent tight junctions. This mechanism drives tumor progression but can be targeted via TROP2-directed therapy to activate antitumor immunity and enhance immunotherapy response.

Abstract Background: Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer and remains difficult to treat due to the absence of targeted therapies. While recent advances in immunotherapy, particularly with immune checkpoint inhibitors (ICIs), have transformed the treatment landscape for many cancers, response rates to ICIs remain low for TNBC, largely due to tumor-intrinsic immune evasion mechanisms. Objective: We identify and characterize a novel immune evasion pathway in TNBC driven by deregulation of cancer cell-intrinsic protease-activated receptor 1 (PAR1), a thrombin receptor frequently upregulated in aggressive tumors. Methods and Results: Through integrative bioinformatic analyses, genetic perturbations, xenograft models (immunodeficient and immunocompetent), flow cytometry-based tumor immune profiling, and RNA-seq, we demonstrate that PAR1 activation enhances immune evasion in TNBC. Mechanistically, we show that the paracaspase MALT1 acts as a critical downstream effector of PAR1 signaling and promotes immune escape by driving PD-L1 expression in TNBC cells. Functional assays reveal that genetic depletion of MALT1 or PD-L1 increases TNBC cell susceptibility to T cell-mediated cytotoxicity in vitro and significantly suppresses tumor growth in vivo. Notably, through knock-in and rescue experiments using a catalytically inactive MALT1 mutant, we reveal that MALT1’s scaffolding - rather than protease - function is essential for PD-L1 regulation. Immune cell depletion assays further identify CD4+ T cells, CD8+ T cells, and natural killer (NK) cells as key mediators of the anti-tumor immune response suppressed by the PAR1-MALT1 axis. These findings are supported by human TNBC specimen analyses, where MALT1 expression inversely correlates with T cell activation and positively associates with PD-L1 in PAR1-high, but not PAR1-low, tumors. Conclusion: Our study reveals immune evasion as a novel mechanism of PAR1-driven breast cancer pathogenesis, mediated by a PAR1/MALT1/PD-L1 signaling cascade. These findings bridge a critical gap by positioning MALT1 at the interface between tumor-intrinsic signaling and the immune microenvironment - two areas of CARMA-BCL10-MALT1 (CBM) complex research that have largely evolved in parallel over the years. Importantly, targeting MALT1 may enhance immunotherapy efficacy in TNBC. Given the availability of MALT1 inhibitors in clinical development, our work supports combining MALT1 inhibition with ICIs or other immune-oncology agents as a promising strategy to overcome immune resistance in TNBC. Citation Format: Dong Hu, Prasanna Ekambaram, Zheqi Li, Linda Klei, Maria L. Beecher, Yi Liu, Zongyou Cai, John Little, Jeffrey A. Meridew, Jia-Ying Lee, E. Aubrey Thompson, Tullia C. Bruno, Lidija Covic, Seung-Oe Lim, Anushka Dongre, Heide L. Ford, Mien-Chie Hung, Adrian V. Lee, Steffi Oesterreich, Linda McAllister-Lucas, Peter C. Lucas. A cancer cell-intrinsic PAR1/MALT1/PD-L1 signaling pathway drives immune evasion in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7392.

Abstract Background: Pediatric and AYA sarcomas are rare, biologically heterogeneous tumors with limited noninvasive biomarkers to guide diagnosis, personalized treatment, and disease monitoring. Standard-of-care evaluation relies on invasive biopsies that carry procedural risks and imaging modalities with limited sensitivity for detecting minimal residual disease and distinguishing tumor types. Cell-free DNA (cfDNA) methylation profiling offers a minimally invasive alternative capable of capturing tumor-derived epigenomic alterations and has consistently shown strong clinical utility in adult malignancies. However, genome-wide cfDNA methylation patterns across diverse pediatric and AYA sarcoma subtypes remain poorly defined. Methods: Plasma was collected from 93 pediatric and AYA patients (pediatric &lt;18 years; AYA 15-39 years) representing 27 Ewing sarcoma, 17 rhabdomyosarcoma, 11 liposarcoma, 10 chordoma, 8 synovial sarcoma, 7 chondrosarcoma, 6 osteosarcoma, and 6 fibrosarcoma cases, plus 19 matched healthy donors. cfDNA was isolated from 1 mL plasma, quantified by Qubit, and assessed by Bioanalyzer. Libraries were prepared using the NEBNext EM-seq v2 workflow with PCR cycles scaled to cfDNA input amount. Genome-wide sequencing (15× target depth) was followed by alignment, deduplication, and methylation calling. MultiQC was used to assess depth, duplication rate, conversion efficiency, and CpG coverage. Global methylation summaries were computed, and methylKit was used to generate per-CpG and 1-kb tiling matrices and initiate differential methylation analyses. Results: Ewing sarcoma patients had significantly higher plasma cfDNA concentrations than age- and sex-matched healthy donors (24.4 vs 4.6 ng/mL, p &lt; 0.0001), whereas cfDNA levels for other sarcoma subtypes overlapped with the healthy cohort. Low or undetectable cfDNA concentrations by Qubit were far more common among non-Ewing sarcoma samples (23 of 66) than Ewing sarcoma (1 of 27). All samples achieved sufficient CpG coverage for genome-wide methylation modeling. Global methylation summaries revealed no significant differences in mean β-values across sarcoma subtypes or versus healthy donors. An independent analysis of the Ewing subset identified 299 significant differentially methylated regions (DMRs), supporting the detectability of disease-specific methylation changes. Conclusions: These results demonstrate the feasibility of high-quality cfDNA methylome profiling across a large and diverse pediatric and AYA sarcoma cohort, including in plasma samples with cfDNA concentrations below the limit of detection. While global methylation levels appear broadly similar across subtypes, proof-of-concept DMR analysis in Ewing sarcoma suggests that subtype-specific epigenomic signatures could enable future noninvasive diagnostic tools for pediatric and AYA sarcomas. Citation Format: Lilli J. Greiner, Roman O. Kowalchuk, Jeff Szymanski, Pradeep S. Chauhan, Adam Amundson, Peter J. Schoettler, Wendy Allen-Rhoades, Stephanie F. Polites, Peter S. Rose, Kelly Bailey, Linda McAllister-Lucas, Anita Mahajan, Nadia Laack, Aadel Chaudhuri. Defining genome-wide cfDNA methylation landscapes in pediatric and adolescent and young adult (AYA) bone and soft-tissue sarcomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7885.

Abstract Background: Chronic inflammation is implicated in ovarian carcinogenesis, but how different inflammation-related exposures individually or jointly affect histotype-specific associations remains unclear. Materials and Methods: We pooled data from 16 case-control studies in the Ovarian Cancer Association Consortium to evaluate associations of eight inflammation-related factors (anti-inflammatory: aspirin use, tubal ligation (TL); pro-inflammatory: endometriosis, obesity, lifetime ovulatory cycles (LOC), smoking, pelvic inflammatory disease (PID), polycystic ovary syndrome (PCOS)) with epithelial ovarian cancer (OvC) by histologic subtype. We examined individual associations and clustering of risk factors across histotypes and computed population attributable risk (PAR) for each factor. We assessed additive and multiplicative interactions for exposure combinations. Results: Associations with OvC risk differed by histotype (e.g., high-grade serous: aspirin: OR=0.90; 95%CI 0.82, 0.99; TL: OR=0.80; 95%CI 0.73, 0.88; overall serous: endometriosis: OR=1.17; 95%CI 1.03, 1.31; high LOC: OR=1.42; 95%CI 1.28, 1.58; obesity (low-grade serous): OR=1.50; 95%CI 1.14, 1.98). Clustering analyses showed highly correlated risk profiles in endometrioid and clear cell (r=0.91). High-grade serous and mucinous profiles were moderately correlated with endometrioid and clear cell (r=0.60) tumors. The profile for low-grade serous (r=0.36) tumors was distinct from other histotypes. PAR estimates suggested modifying aspirin use, TL, and LOCs could substantially reduce burdens of endometrioid, clear cell and mucinous tumors. Out of 28 exposure combinations tested in overall OvC and 189 by histotype, we observed 12 interactions. Not using aspirin regularly showed positive additive interactions with obesity and high LOCs, particularly in endometrioid tumors (obesity relative excess risk due to interaction (RERI)=0.74, 95%CI 0.31, 1.18; Pint=0.001 for; LOCs RERI=0.80, 95%CI 0.03, 1.56; Pint=0.04). Not using aspirin regularly also showed a positive additive interaction with endometriosis in clear cell tumors (RERI=1.77, 95%CI 0.03, 3.52; Pint=0.05). Lack of TL showed positive interactions with obesity in endometrioid (RERI=0.86, 95%CI 0.17, 1.53; Pint=0.01) and mucinous (RERI=1.10, 95%CI 0.23, 1.97; Pint=0.01) tumors, while negative additive interactions were observed for smoking and endometriosis in endometrioid tumors (RERI=-1.12, 95%CI -2.19, -0.05; Pint=0.04). A multiplicative interaction was observed between obesity and endometriosis in mucinous tumors (Pint=0.01). Conclusion: The findings suggest ovarian tumorigenesis is strongly shaped by pro- and anti-inflammatory pathways that act largely independently. Further examining these pathways may clarify the origins of histotype heterogeneity and guide prevention strategies. Citation Format: Maxwell Akonde, Britton Trabert, SHELLEY TWOROGER, Allan Jensen, Kathryn L. Terry, Joshua Sampson, Hoda Anton-Culver, David Bowtell, Elisa V. Bandera, Angela Brooks-Wilson, Andrew Berchuck, Daniel William Cramer, Linda S. Cook, Julie M. Cunningham, Jennifer A. Doherty, Ellen L. Goode, Marc T. Goodman, Holly Ruth Harris, Susanne K. Kjaer, Nhu Le, Alice Wen-Ron Lee, Francesmary Modugno, Kirsten B. Moysich, Celeste Pearce, Malcolm C. Pike, Harvey A. Risch, Mary A. Rossing, Joellen M. Schildkrau, Daniel O. Stram, Rebecca Sutphen, David Van Den Berg, Penelope M. Webb, Anna Wu, Argyrios Ziogas, Nicolas A. Wentzensen. Inflammation-related exposures and histotype- specific ovarian cancer risk in the Ovarian Cancer Association Consortium (OCAC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6261.

Abstract Introduction/Objectives: The CARMA1-BCL10-MALT1 (CBM) signalosome plays crucial role in mediating antigen receptor-induced activation of NF-κB transcription factor and subsequent lymphocyte activation. The effector protein of the signalosome, MALT1, functions both as a scaffold to recruit downstream NF-κB signaling machinery, and as a protease to cleave and inactivate multiple substrates including negative regulators of NF-κB. Constitutive MALT1 activation, which can occur as a result of gain-of-function mutations of the B cell receptor, CARMA1, BCL10 or chromosomal translocation involving the MALT1 gene, underlies the pathogenesis of multiple lymphoid malignancies including activated B-cell type-diffuse large B-cell lymphoma (ABC-DLBCL) and MALT lymphoma. We previously identified G-protein-coupled receptor kinase 2 (GRK2) as a tumor suppressor in MALT1-dependent lymphomas which binds MALT1 and inhibits MALT1 scaffolding and proteolytic activities. Accordingly, GRK2 mRNA levels are markedly lower in a subset of DLBCL tumors compared to normal B cells and lower GRK2 level in ABC-DLBCL is associated with reduced patient survival. In current study, we sought to investigate the mechanism of how GRK2 levels are regulated in ABC-DLBCL. Methods/Results: Using DICER1 depleted cells, we showed that globally impaired miRNA processing leads to increased GRK2 protein levels. We then conducted bioinformatic analyses of patient tumor samples and performed screening via microRNA Data Integration Portal to identify microRNAs that target GRK2 in ABC-DLBCL. Further GRK2 3’UTR reporter assay confirmed direct targeting of GRK2 by candidate miRNAs. ABC-DLBCL cell lines, OCI-LY3 and TMD8, which demonstrate reduced GRK2 mRNA expression compared to primary B cells, show elevated expression of candidate GRK2-targeting microRNAs. Stable overexpression of miR-125a, 125b, or 148b in OCI-LY3 or TMD8 cells led to reduced GRK2 expression, enhanced MALT1 activity and increased cell proliferation. Conversely, in vitro inhibition of candidate miRNAs using anti-miRNA Locked Nucleic Acids (LNA) inhibitors led to enhanced GRK2 expression, reduced MALT1 activity and decreased cell proliferation. Importantly, treatment of mice with inhibitors of miR-125b and miR-148b abrogates the growth of ABC-DLBCL xenograft tumors in vivo. Conclusion: We have identified miRNAs that negatively regulate GRK2 expression in ABC-DLBCL. These GRK2-targeting miRNAs serve a pro-tumorigenic role by promoting MALT1 oncoprotein’s scaffold and protease activity. Furthermore, inhibitors of these miRNAs can enhance GRK2 expression and thereby suppress MALT1 activity and MALT1-dependent tumor cell proliferation, both in vitro and in vivo. These studies suggest that microRNA inhibitors which enhance GRK2 expression could represent a novel approach for restraining MALT1-dependent lymphomagenesis. Citation Format: Jing Cheng, Mei Smyers, Matt Trotta, Neil M. Carleton, Lisa M. Maurer, Uma R. Chandran, Min Xia, Ari M. Melnick, Peter C. Lucas, Linda M. McAllister-Lucas. MicroRNAs targeting tumor suppressor GRK2: Novel potential therapeutic strategies for restraining MALT1-dependent DLBCL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2061.

Abstract The detection of genetic abnormalities is required during diagnostic workup and for potential individualization of therapy selection in multiple myeloma (MM) and its precursor conditions. At present, this relies on invasive bone marrow (BM) biopsies, severely limiting early detection, frequent longitudinal monitoring, and the precise selection of therapy. The current standard for detecting genetic alterations in MM is fluorescence in situ hybridization (FISH), which cannot detect point mutations and other clinically relevant alterations. Consequently, the IMS-IMWG guidelines were recently updated to require next-generation sequencing for the classification of high-risk MM. To address these needs, we recently launched GenoPredicta, a CLIA-approved LDT that enables routine monitoring, informing diagnosis, and treatment selection by comprehensively characterizing MM genomes with whole genome sequencing (WGS) from as few as 50 circulating tumor cells (CTCs) isolated from peripheral blood (PB) or tumor cells from BM. Briefly, tumor cells are isolated from samples using fluorescence-activated cell sorting and subjected to WGS, from which copy number alterations, structural variants, and short variants (SNVs/indels) are identified using a fully automated pipeline generating physician-ready clinical reports from raw sequencing data in ∼6h. Analytical validation of GenoPredicta showed complete concordance with FISH results. Identifying alterations in therapeutic targets (e.g., BCMA, GPRC5D) for guiding MM immunotherapies is becoming increasingly important. Here, we describe GenoPredicta results from relapsed/refractory MM patients, highlighting resistance-conferring alterations that can only be detected by WGS, such as deletions in the kilo- to megabase scales that are observed in conjunction with SNVs and indels, leading to biallelic loss/inactivation of the gene, including at subclonal levels. In addition to biallelic loss of BCMA and GPRC5D in response to CAR T or T cell engager therapies, we observed similar resistance mechanisms for targets of immunomodulatory drugs, e.g., CRBN. The observation of these resistance mechanisms was consistent with patients’ clinical histories. In summary, we demonstrate that low input WGS-based characterization of MM from BM or CTCs is a viable replacement for FISH for clinical diagnosis and monitoring, with CTC-based measurements enabling comprehensive profiling of the MM genome. Crucially, this includes genetic alterations that confer resistance to therapy, allowing for both early detection of such alterations and more precise selection and guidance of therapy. The dramatically improved variant calling ability from WGS, especially in low-input CTC applications, extends to other malignancies and will gain wider adoption as sequencing costs continue to decrease. Citation Format: Bruno Paiva, Peter Voorhees, Patricia T. Greipp, Danielle Sookiasian, Julian Hess, Marisa DeMeo, Vicki Pounder, Sarah Calkins, Reid Meyer, Linda B. Baughn, Christine-Ivy Liacos, Meletios-Athanasios Dimopoulos, Alexandra Papadimou, Taouxi Konstantina, Efstathios Kastritis, Jesus Berdeja, Daniel Auclair, Valentina Nardi, Thomas Mullen, Francois Aguet, Shaji Kunnathu Kumar. Whole genome sequencing of multiple myeloma genomes with a novel clinical assay enables identification of genetic alterations underlying immunotherapy resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1067.