Citations

Abstract RMC-6236 (daraxonrasib) is a novel multiselect RAS(ON) inhibitor under investigation for pancreatic ductal adenocarcinoma (PDAC) and other RAS-mutant cancers. This compound shares structural similarities with RMC-7977 and exhibits a conserved binding site and interaction pattern within the tri-complex formed between active RAS (RAS(ON)) proteins and cyclophilin A (CypA). Tumor Treating Fields (TTFields) are low-intensity, alternating electric fields that disrupt mitosis and have shown clinical benefit in solid tumors. The PANOVA-3 trial demonstrated that TTFields combined with gemcitabine plus nab-paclitaxel improved survival, pain control, and quality of life in locally advanced PDAC. Our previous work demonstrated that TTFields abrogate oncogenic KRAS pathway. We thus hypothesize a potential for increase in effectievness with the combination. In this study, the metastatic PDAC cell line AsPC-1 was treated with TTFields (150 kHz, 1.8 V/cm), RMC-6236 (15 nM; sub-IC50), or combination. A sub-IC50 concentration (15 nM) of RMC-6236 was selected based on MTS assay results, and subsequent experiments were performed at this dose. The MTS assay revealed that both TTFields and RMC-6236 independently reduced AsPC-1 cell viability, with a more pronounced reduction observed at 72 hours compared to 48 hours. RMC-6236 alone produced minimal effects at either 48 hours (85.82 ± 13.9%) or 72 hours (90.48 ± 15.4%) compared with control (100.0 ± 8.4%, 48 h; 100.0 ± 8.2%, 72 h). TTFields treatment significantly reduced viability to 74.42 ± 21.4% at 48 hours and 50.17 ± 26.5% at 72 hours. The combination treatment (TTFields + RMC-6236) further decreased viability to 63.8 ± 25.2% at 48 hours and 40.93 ± 18.1% at 72 hours, demonstrating synergistic cytotoxicity relative to monotherapy. Clonogenic assays were performed to evaluate cell survival fractions following treatment with RMC-6236, TTFields, and their combination. Cell migration was assessed using scratch assays, revealing that untreated cells exhibited a migration rate of 91.49 ± 0.85%, RMC-6236-treated cells showed 89.48 ± 1.3%, TTFields alone reduced migration to 61.33 ± 16.3%, and combination treatment markedly suppressed migration to 24.6 ± 22.13% . For every case we were compared with 72h cell migration rate with 0 h migration rate. These findings indicate that TTFields alone significantly impair cellular motility, while their combination with RMC-6236 results in a profound anti-migratory effect, substantially inhibiting wound closure. Additionally, western blot analysis was performed to assess changes in KRAS protein expression, a key PDAC biomarker. Overall, our results demonstrate that the combination of TTFields and RMC-6236 significantly inhibits PDAC cell growth, migration, and survival at sub-IC50 concentrations, suggesting a promising alternative therapeutic approach for PDAC management. Citation Format: Ishita Saha, Santanu Bhattacharya, Debabrata Mukhopadhyay, Hani M. Babiker. Synergistic antitumor activity of tumor-treating fields and multiselect-RAS (ON) inhibitor RMC-6236 in pancreatic ductal adenocarcinoma [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 4478.

Abstract Introduction: Clinical staging of multifocal non-small cell lung cancer (NSCLC) is facilitated by comparative genomic analysis of separate tumor nodules, but the role of genome-wide copy number profiling for this purpose is uncertain. Methods: We analyzed single nucleotide variants (SNVs), gene fusions, small copy number variants (gene amplifications and homozygous deletions) (sCNVs), and large-scale copy number variants (lCNVs) in a retrospective cohort of 34 patients with >1 lung cancer nodule tested on a previously validated tumor-only 515-gene next generation sequencing (NGS) panel (MayoComplete Solid Tumor Panel). For patients with <2 shared SNVs, a Bayesian approach was formulated to calculate the probability of shared versus independent events occurring in different tumor nodules in the same patient. The prevalence of specific lCNVs in NSCLC was derived from an independent dataset of 100 NSCLC peers tested by the same panel, and the prevalence of SNVs, fusions, and sCNVs in NSCLC was derived from publicly available data. Alterations unique to different tumor nodules and suspected germline alterations were excluded from the Bayesian analysis. Results: There were 54 total comparisons for 34 patients. Eleven of the patients (32.4%) had >=2 shared SNVs along with one or more shared lCNVs also identified in each patient. Eight patients (23.5%) had no shared SNVs, gene fusions, sCNVs, or lCNVs. Using the Bayesian approach for the remaining fifteen (44.1%) patients with at least one shared alteration (SNVs, sCNVs, and lCNVs), the probability of clonal relatedness ranged from 73% for a shared whole arm or whole chromosome lCNV to >99% for tumors with two or more shared alterations including multiple or complex lCNVs and SNVs. Whole chromosome or whole arm lCNVs were sometimes shared between tumor nodules with different driver SNVs. Conclusions: Incorporating lCNVs into comparative genomic analysis provides additional evidence of clonal relatedness in a subset of multifocal NSCLCs. However, differences in bioinformatics pipelines for calling lCNVs, concerns over the imprecision of genome-wide copy number profiling, and uncertainty regarding the temporal relationship between lCNVs and carcinogenesis (including somatic events possibly related to “field cancerization”) create challenges for integrating lCNVs into comparative genomic analysis with standard clinical workflows for tumor-only NGS on paraffin embedded tissue sections. Our simplified approach mitigates some of the uncertainty introduced by incorporating lCNVs into clonality determination. Citation Format: Claire Teigen, Ying-Chun Lo, Sounak Gupta, Stephanie Smoley, Beth Pitel, Hussam Al Kateb, Gopi Sivasankaran, Benjamin Kipp, Ande Rumilla, Gang Zheng, Kevin Halling, Katherine Geiersbach, . A Bayesian framework for evaluating somatic copy number variants into comparative genomic analysis of multifocal non-small cell lung 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 5423.

Abstract Approximately 288,000 men are diagnosed with prostate cancer (PCa) in the United States each year, with cases expected to double by 2040. While metastatic PCa can be treated with androgen deprivation therapy (ADT) and AR pathway inhibitors (ARPI), it inevitably develops into treatment resistant, lethal disease. The most common ARPI resistance mechanism in PCa is the expression of AR splice variant AR-V7 that lacks the ligand binding domain and is constitutively active. Patients with PCa expressing AR-V7 experience inferior overall survival. Speckle-type POZ protein (SPOP) is an adaptor protein of the Cullin3-based E3 ubiquitin ligase that facilitates both degradative and non-degradative polyubiquitination of targets such as AR. Loss-of-function SPOP mutations occur in approximately 10-15% of prostate cancers, and SPOP-mutant PCa is a unique subtype that has been shown to be exquisitely sensitive to ADT and ARPI treatment. This sensitivity is mediated in part by increased androgen availability via upregulation of hydroxysteroid 17-beta dehydrogenase 4 (HSD17B4) and related steroid synthesis pathways, reduced AR degradation, and enhanced AR cofactor activity. The remarkable efficacy of ARPI in ADT-resistant SPOP-mutant prostate cancer is not well understood. We hypothesized a novel mechanism by which wild-type SPOP promotes AR-V7-mediated resistance to ARPI in PCa. This mechanism may explain the exceptional ARPI sensitivity of SPOP-mutant PCa, distinct from its susceptibility to ADT. We further proposed that clinical SPOP inhibition may broaden this enhanced ARPI susceptibility to the 85-90% of PCa expressing wild-type SPOP. Our results show that SPOP drives ARPI resistance in prostate cancer that can be reversed by SPOP inhibitor. Bulk RNA sequencing showed that SPOP inhibitor targets spliceosome machinery and more importantly, abrogated AR-V7 expression both at transcriptional and protein level. Further investigation revealed that wild-type SPOP ubiquitinates spliceosome regulator SFPQ, promoting AR-V7 alternative splicing and ARPI resistance. While SPOP loss is pathogenic in PCa, leveraging the weakness conferred by SPOP mutation in the 85% of patients with SPOP-wild type provides an innovative strategy to sensitize ARPI resistant disease to standard of care treatment and save lives. Citation Format: Joanina K. Gicobi, Susanna M. Gregory, Nicole A. Becker, Elizabeth A. Bering, Jacob J. Orme.. SPOP drives AR-V7-mediated ARPI resistance in prostate 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 3904.

BACKGROUND: Catheter ablation for atrial fibrillation is a widely used rhythm-control strategy, yet its role in reducing thromboembolic risk and enabling oral anticoagulation (OAC) discontinuation remains uncertain. This meta-analysis aims to comprehensively synthesize and evaluate randomized controlled trial evidence supporting long-term antithrombotic strategies in patients with atrial fibrillation undergoing catheter ablation. METHODS: A systematic literature search was performed in MEDLINE/PubMed, Embase, and the Cochrane Central Register of Controlled Trials to identify randomized controlled trials evaluating antithrombotic strategies after catheter ablation for atrial fibrillation. The primary outcome was ischemic stroke. A frequentist network meta-analysis comparing reported treatment arms, along with a pooled incidence meta-analysis for outcomes of interest, was conducted. RESULTS: Four randomized controlled trials, including 3924 patients, met the inclusion criteria. Three trials compared long-term OAC continuation versus OAC discontinuation, and 1 compared OAC continuation with left atrial appendage occlusion after catheter ablation. No significant differences in stroke incidence were observed when comparing OAC or left atrial appendage occlusion with no antithrombotic therapy (incidence rate ratio, 0.90 [95% CI, 0.02–33.85]; P =0.95; incidence rate ratio, 0.79 [95% CI, 0.00–241.01]; P =0.94, respectively). Among patients who discontinued antithrombotic therapy without undergoing left atrial appendage occlusion (n=1161), with 2864 cumulative person-years of follow-up, the pooled incidence of stroke was 0.23 events per 100 person-years (95% CI, 0.02–2.43; I 2 =0%). CONCLUSIONS: This analysis reinforces that, across randomized data, the incidence of thromboembolic events in patients who discontinued OAC after successful ablation remained low. However, the evaluation of net clinical benefit is limited by the low number of events across all treatment arms, underscoring the need for larger studies with prolonged follow-up to further validate the safety of this strategy, particularly in higher-risk populations.

Abstract Renal tumors are highly heterogeneous, ranging from benign lesions and indolent renal cell carcinoma (RCC) to highly aggressive phenotypes. Accurately determining tumor aggressiveness before treatment remains a major clinical challenge. Conventional MR imaging lacks sensitivity to microarchitectural differences underlying tumor biology, and biopsy is limited by sampling error and tumor heterogeneity. Radiomics offers a noninvasive approach to extract high dimensional features that may capture biologically relevant patterns. In this IRB-approved retrospective study, we evaluated MR-based radiomics combined with machine learning (ML) to differentiate indolent from aggressive tumors. Pre-operative clinically acquired MR images obtained from eighty-two RCC patients (aggressive, n = 56; indolent, n = 26) who underwent nephrectomy were included for the analysis. Regions of interest (ROIs) of the entire tumor were manually drawn using 3D Slicer on the morphological T2-weighted images and four phases (pre-contrast [PRE], corticomedullary [CM], nephrographic [NG], and delayed [DEL]) from the contrast-enhanced MR images, normalized, and used for radiomic feature extraction (PyRadiomics, v3.1.0). Independently, tumors were grouped into aggressive and indolent phenotypes based on the established histological classification of Mayo Clinic. Statistical analysis used two-sided t-test. Features selected based on mutual information were used for ML classification (Random Under-Sampling Boosting (RUSBoost)) and performance assessed using accuracy, sensitivity, precision, specificity, F1-score, and area under the curve (AUC). Of 107 radiomics features extracted, the following numbers showed statistically significant differences between aggressive and indolent tumors (p < 0.05): CM phase (n = 19), NG phase (n = 24), DEL phase (n = 22), and T2-weighted images (n = 29). Several features consistently differed among contrast-enhanced images and included first-order (length, surface area, volume), GLCM (correlation, IDM, IMC1, IMC2), GLDM (dependence entropy, dependence non-uniformity, dependence variance), GLRLM (gray-level non-uniformity, run entropy, run-length non-uniformity), GLSZM (high gray-level emphasis, zone entropy), and NGTDM (coarseness). Using the 15 features with highest mutual information across 50 patients (aggressive, n = 31; indolent, n = 19), a five-fold cross-validation RUSBoost classifier achieved accuracy 0.81, sensitivity 0.84, precision 0.87, specificity 0.77, F1-score 0.85, and AUC 0.80 for identifying the aggressive phenotype. MRI radiomics features show potential to differentiate aggressive from indolent renal tumors. ML-based classification using these features demonstrates promising accuracy. Further optimization and validation in larger cohorts, may help guide individualized care, including consideration of active surveillance for indolent renal tumors. Citation Format: Huan Lu, Salim Rukhsar, Xueqing Yin, Garima Suman, Ashish Khandelwal, Ananth J. Madhuranthakam, Durga Udayakumar. MRI radiomic features to differentiate aggressive and indolent renal tumors [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 2142.

Abstract Background: Liquid biopsy approaches for cancer detection often rely on tissue-specific methylation or fragmentation features to infer tumor origin. However, a pan-aerodigestive cancer detection strategy is clinically valuable given shared risk exposures, field cancerization, and frequent diagnostic ambiguity among lung, esophageal, and head & neck cancers. We hypothesized that advanced-stage disease exhibits convergent chromatin remodeling, producing a dominant malignancy-associated fragmentomic signal that supersedes subtler tissue-of-origin patterns. Methods: Whole-genome EM-seq (∼15×) was performed on plasma cfDNA from 120 patients with stage III/IV aerodigestive cancers (lung, esophageal, head & neck; squamous and adenocarcinoma) and 60 age-matched controls. Four fragmentomic modalities were assessed: (1) genome-wide fragmentation in 5-Mb bins (DELFI-like), (2) NMF spectral components, (3) 4-mer end motifs, and (4) promoter-centric nucleosome scores (Griffin). All preprocessing occurred strictly within each training fold of a repeated stratified 10-fold CV (100 repeats) to prevent data leakage. No test-sample information was used in training. Hyperparameters were tuned only within training partitions. Random Forest classifiers were trained under this fully nested scheme. Results: The multimodal classifier robustly detected advanced aerodigestive malignancies with a mean AUROC 0.86 and AUPRC 0.94. However, modality dissection revealed a clear performance hierarchy: nucleosome positioning (Griffin) alone achieved AUROC 0.85 and AUPRC 0.93, nearly matching the full integrated model, whereas end motifs performed poorly (AUROC 0.61). Biological interpretation demonstrated prominent nucleosome depletion centered at promoters of proliferation-associated genes, indicating a convergent epigenetic state of promoter opening across late-stage aerodigestive malignancies. Conclusions: Advanced aerodigestive cancers exhibit a dominant, convergent chromatin remodeling signature detectable in plasma cfDNA, driven primarily by altered nucleosome positioning. In late-stage disease, this shared malignancy-associated fragmentomic signal outweighs tissue-of-origin-dependent patterns. These findings highlight the utility of nucleosome-based fragmentomics not merely for detection, but for resolving diagnostic ambiguity in patients with indeterminate masses and for monitoring total tumor burden in high-risk aerodigestive malignancies. Citation Format: Axel Misael Hidalgo, Ayesha Hashmi, Jeff Szymanski, Pradeep Chauhan, Lilli Greiner, Faridi Qaium, Daniel J. Ma, David M. Routman, Katie M. Van Abel, Aadel A. Chaudhuri.. Convergent chromatin remodeling enables pan-aerodigestive detection of advanced malignancies in plasma cfDNA [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 3862.

Abstract Therapeutic resistance limits the efficacy of radiation therapy in many tumors and provides a compelling rationale to develop novel treatments to enhance radiation sensitivity. DNA-dependent protein kinase (DNA-PK) is a major mediator of DNA repair following radiation, and DNA-PK inhibitors are effective radiosensitizers. WNC0901 is a potent DNA-PK inhibitor in both a cell-free kinase assay (IC50 = 0.073 nM) and a cell-based assay (IC50 = 76 nM). WNC0901 has a 30-fold specificity for DNA-PK relative to other PI3K-related kinases. In a broader kinome screen (363 kinases), 1 μM WNC0901 resulted in >25% inhibition of only five other kinases. There is robust inhibition of radiation-induced DNA-PK autophosphorylation (Ser-2056), as analyzed by Western blotting, with maximal effect at 300 nM WNC0901 in A549 (lung carcinoma), U2OS (osteosarcoma), and HT29 (colorectal) cells. The efficacy of WNC0901 as a radiosensitizer was evaluated in clonogenic assays across these same three radioresistant tumor models. Following treatment with graded concentrations of WNC0901 (0-1000 nM) combined with 2.5 Gy radiation, maximal effects were observed at a 300 nM concentration in A549 (88-fold reduction in relative clonogenic survival compared to RT alone, p<0.001), U2OS (5.8-fold decrease, p=0.002), and HT29 (59-fold decrease, p=0.008) In a full radiation clonogenic, the sensitizer enhancement ratio at 10% survival (SER10) was 3.8 (A549), 2.3 (U2OS), and 1.8 (HT29). In vitro metabolism studies have identified demethylated WNC0901 (WNC0901-M) as a major metabolite. Similar to the parent drug, WNC0901-M is a potent DNA-PK inhibitor with maximal radiosensitizing effects of the metabolite observed at 300nM with SER10 of 2.4 (A549), 1.9 (U2OS), and 1.8 (HT29). The in vivo efficacy of 50 mg/kg WNC0901 combined with 8 Gy was evaluated and compared to another DNA-PK inhibitor, 50 mg/kg peposertib, in A549 tumor heterotopic xenografts. Compared to placebo (median time to endpoint 63 days) or RT alone (median 72 days), the combination of WNC0901 and RT significantly delayed tumor regrowth (median 169 days; p=0.002 compared to RT). Interestingly, peposertib + RT was ineffective (median 83 days; p=0.332 compared to RT). In a second study, similarly robust sensitizing effects of WNC0901 was observed in HT29 xenografts (placebo - median 45 days; RT - median 75 days; RT + WNC0901 - median >110 days; p=.03 relative to RT). Together, these findings demonstrate the robust radiosensitizing effects of WNC0901 in radioresistant tumors and provide a rationale for continued development of this drug. Citation Format: Jessica L. Abraham, Ann C. Mladek, Sonia Jain, Shiv K. Gupta, Paul A. Decker, Matthew L. Kosel, Katrina K. Bakken, Brett L. Carlson, Lauren L. Ott, Danielle M. Burgenske, Jeanette E. Eckel-Passow, Wei Zhong, Jann N. Sarkaria. WNC0901 is a novel DNA-PK inhibitor and potent radiosensitizer of otherwise radioresistant solid tumors [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 6608.

Abstract Background: Multiple myeloma is the second most common adult blood cancer and remains incurable, despite recent advances. The IMWG/IMS recently published updated risk criteria, Consensus Genomic Staging (CGS), combining genomic events with clinical measures to identify high-risk patients (Avet-Loiseau, et al. JCO 2025). We applied CGS risk criteria to baseline samples from the Multiple Myeloma Research Foundation CoMMpass Study (NCT01454297), a prospective, longitudinal observational study that enrolled more than1100 participants between 2011-2017. Methods: We assessed patient risk following CGS criteria. Criteria 1: del(17p), with a cutoff of >20% clonal fraction, and/or TP53 mutation. Criteria 2: an IgH translocation including t(4;14), t(14;16), or t(14;20) along with 1q+ and/or del(1p32). Criteria 3: monoallelic del(1p32) along with 1q+ or biallelic del(1p32). Criteria 4: beta-2 microglobulin >= 5.5 mg/L with normal creatinine. Patients meeting one or more criteria were classified as High Risk. To test if risk showed association with genetic ancestry, we grouped patients into those with high African genetic ancestry and those with low African genetic ancestry. Genetic ancestry was measured using ADMIXTURE in comparison to 1000 Genomes. Results: We evaluated the CGS risk status of 877 CoMMpass patients, finding 69.2% (573/828) to be Standard Risk (SR) and 30.8% (255/828) to be High Risk (HR). HR patients showed worse progression-free survival (median PFS 26.3 months vs. 42.5 months; log rank test, p < 0.0001) and overall survival (median OS 63.9 months vs. median not reached; p < 0.0001). 10.6% (91/858) of patients met Criteria 1, 10.7% (93/873) met Criteria 2, 5.6% (49/877) met Criteria 3, and 8.7% (73/835) met Criteria 4. We found 14.2% (123/867) of patients to have high African-like genetic ancestry (AFR-high) and 85.8% (744/867) to have low African-like genetic ancestry (AFR-low). We observed significantly fewer HR patients within the AFR-high group (20%, 23/115) than in the AFR-low group (32.4%, 231/712) (Fisher’s exact test, p = 0.0065). The AFR-high group met HR criteria at a lower rate across all criteria, but only with Criteria 3 was the difference significant (p-value = 0.03). Higher levels of creatinine in AFR-high patients may have impacted meeting the normal creatinine requirement of Criteria 4. Conclusions: HR patients comprise 30.8% of CoMMpass subjects and show significantly worse PFS and OS than SR patients. AFR-high patients met HR criteria at a lower rate than AFR-low patients according to the CGS criteria. Clinical trials that utilize CGS criteria to determine patient eligibility may be challenged to enroll a representative patient population, including AFR-high patients. Screening and eligibility criteria should be carefully considered to mitigate potential enrollment disparities. Citation Format: Steven M. Foltz, Chaitanya R. Acharya, Alexander Gout, Yuxin Jin, David E. Avigan, Ravi Vij, Shaji Kunnathu Kumar, Sagar Lonial, Hearn Cho, Katie Wozniak, Jonathan J. Keats, Craig Cole, John D. Carpten, George J. Mulligan. Multiple myeloma risk classification of CoMMpass using Consensus Genomic Staging identifies differences between patients with high and low African genetic ancestry [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 3887.

Abstract Circulating tumor DNA (ctDNA)-based minimal residual disease (MRD) detection is a paradigm shift for risk stratification in early-stage breast cancer (eBC) surveillance. While the prognostic signal is clear, comprehensive synthesis across molecular subtypes remains limited, hindering the translation of prognostic findings into actionable, intervention-guided trials. We conducted a systematic review and meta-analysis following PROSPERO registration (CRD420251122005). Databases including PubMed/MEDLINE, Embase, and Cochrane CENTRAL were searched through September 2025. Studies involving eBC (stage I-III) patients with ctDNA-based MRD detection using validated assays, survival outcomes, and ≥12 months follow-up were included. Random-effects meta-analysis assessed the pooled hazard ratio (HR) for disease recurrence. Subgroup analyses explicitly evaluated molecular subtypes (TNBC, HER2+, HR+/HER2-) based on detection performance and gene mutation profiles. From 1,246 records, 59 studies were included, encompassing 12,847 eBC patients. Meta-analysis demonstrated an extreme prognostic value of disease-free survival from 26 studies with a pooled HR of 9.95 (95% CI: 6.50-15.25, p<0.0001). High heterogeneity was observed (I2=67.2%), largely driven by differences in tumor biology and assay technology. Subtype-specific analysis highlighted distinct shedding rates: TNBC showed the highest baseline detection (80−83.8%) and sensitivity (85−90%). HR+/HER2-showed the lowest baseline detection (14.6−30%). Gene mutation analysis revealed actionability: TP53 predominated in TNBC, while PIK3CA, ESR1, and AKT1 mutations were more frequent in HR+/HER2- disease. Crucially, the time from ctDNA detection to clinical recurrence provided a consistent median lead time of 10.2 months (range 7.5−16months), with cases detected up to 68 months prior. Specificity exceeded 95% across all subtypes. This meta-analysis establishes ctDNA-based MRD detection as a clinically valid biomarker with a nearly 10-fold increased recurrence riskin ctDNA-positive patients. The high heterogeneity underscores the necessity of tailored, subtype-specific surveillance protocols and selection of ultra-sensitive assays. The consistent ∼10-month lead time defines a critical intervention window, providing a clear rationale for ongoing and future randomized clinical trials evaluating ctDNA-guided therapeutic intensification against the distinct molecular profiles observed in each breast cancer subtype. Citation Format: Panuch Eiamprapaporn, Thiti Susiriwatananont, Yaohua Ma, Hataiwan Ratanabunjerdkul, Panchanin Patanayindee, Lucksika Wanichtanom, E. Aubrey Thompson, Saranya Chumsri. Prognostic utility of minimal residual disease detection using circulating tumor DNA in early-stage breast cancer: A systematic review and meta-analysis [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 5380.

Abstract Background: Hypogammaglobulinemia at the time of CLL diagnosis predicts shorter time to first therapy (TTFT). However, the depth of immunoparesis and its impact on TTFT in newly diagnosed MBL/CLL remains unexplored. Methods: We identified previously untreated MBL/CLL patients from Mayo Clinic CLL Database (2000-2024) who had serum immunoglobulin (Ig; IgG, IgM and IgA) and monoclonal protein assessed within 1 year of diagnosis. Immunoparesis was evaluated: a) qualitatively by classifying patients into preserved, partial and full Ig suppression, based on the number of suppressed Igs; and b) quantitatively by calculating the average relative difference (ARD), defined as the mean percentage below normal for all Igs. For both methods, only uninvolved Igs were considered for those with monoclonal protein. TTFT was estimated by Kaplan-Meier with competing risk of death. Cox models estimated hazard ratios (HR) and 95% confidence intervals (CI). Results: Among 1420 patients, median age at diagnosis was 65 (range 28-96); 954 (67%) were male; 493 (44.8%) had unmutated IGHV, and 86 (6.8%) had TP53 disruption. The median [range, mg/dL] serum IgG, IgA, and IgM were 889 [111-5290], 132 [1-4880], and 49 [4-9480]. Low IgG was present in 472 (33.2%), low IgA in 223 (16.4%), and low IgM in 530 (37.3%) patients. An M-spike was detected in 122 (8.6%) patients; distribution was: IgG (73), IgM (30), IgA (6), or multiple (13). By qualitative assessment, preserved Ig were seen in 664 (46.8%), partial Ig suppression in 604 (42.5%), and full suppression in 152 (10.7%) patients. By quantitative assessment, median ARD was 0.6 (-0.8 to 11.3); 280 (19.7%) patients had negative ARD, and 1140 (80.3%) had positive ARD. In those with negative ARD, 128 (9%) had partial Ig suppression and 152 (10.7%) had full Ig suppression; in those with positive ARD, 664 (46.8%) had preserved Ig and 476 (33.5%) had partial Ig suppression. Median follow-up was 14.7 years; 510 patients progressed requiring therapy. Median TTFT was 9.6 years. Median TTFT for patients with preserved Ig was 12.6 years, 8.0 years for partial Ig suppression (HR 1.4, 95%CI 1.1-1.7), and 1.8 years for full Ig suppression (HR 3.1, 95%CI 2.4-4.0). The median TTFT was 2.3 and 12.1 years for patients with negative vs positive ARD; negative ARD was associated with shorter TTFT (HR 2.4, 95%CI 2.0-2.9). After adjusting for sex and CLL-International Prognostic Index (CLL-IPI) score, full Ig suppression (HR 2.9, 95%CI 2.2-3.9) and partial Ig suppression (HR 1.6, 95% CI 1.3-2.0) were associated with shorter TTFT (model 1, c-stat 0.77); and negative ARD (HR 2.4, 95%CI 2.0-2.9) was associated with shorter TTFT (model 2, c-stat 0.76). Negative ARD identified an additional 9% of patients at higher risk for shorter TTFT beyond full Ig suppression. Conclusions: The depth of immunoparesis at diagnosis predicts TTFT and enhances risk stratification in newly diagnosed MBL/CLL. Citation Format: Yuan Yao, Kari G. Rabe, Eli Muchtar, Paul Hampel, Yucai Wang, Lindsey Roeker, Saad Kenderian, Amber Koehler, Catherine Wagner, Amy Behnken, Jose F. Leis, Mazie Tsang, Talal Hilal, Ricardo Daniel Parrondo, Susan M. Schwager, Min Shi, Curtis A. Hanson, Celine M. Vachon, Shaji Kunnathu Kumar, Esteban Braggio, Neil E. Kay, Susan Slager, Sameer A. Parikh. Depth of immunoparesis predicts time to first therapy in newly diagnosed monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia [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 1191.