Citations

Abstract 5-Fluorouracil (5FU)-based chemotherapy remains a front-line treatment for most patients with colorectal cancer. However, approximately 30% of patients who receive 5FU experience severe, life-threatening toxicity. Dihydropyrimidine dehydrogenase (DPD, DPYD gene) mediates the rate determining step in 5FU catabolism. Deleterious genetic variations in DPYD have been associated with elevated concentrations of circulating 5FU and significantly increased risk for 5FU toxicity. Five deleterious variants in DPYD have been identified as clinical biomarkers of toxicity and have led to prospective genotyping and differential dosing recommendations for carriers of these variants, as noted on recent updates to the FDA label for the 5-FU prodrug capecitabine. Our previous studies also established the importance of epigenetic control of DPD expression. In this study, we used existing epigenetic repositories to identify candidate enhancer elements for DPYD. We selected 20 novel high-priority putative enhancers for further study using a combination of reporter assays and CRISPRi applied across multiple cell models. Further studies will investigate means to target these regulatory mechanisms as a means to increase localized efficacy of 5-FU-based therapies in colorectal cancer. Citation Format: Hannah Marie Krause, Julia Magee, Kelly Bouchonville, Lauryn Allyn Hahn, Ryan Jonathan Swartz, Brianna Bembenek, Lulu Jiang, Steven M. Offer. Characterizing the critical role of enhancer-gene regulation in 5-fluorouracil toxicity and 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 3140.

Abstract Dihydropyrimidine dehydrogenase (DPD, encoded by the DPYD gene) is the rate-limiting enzyme in the catabolism of the widely used chemotherapeutic drug 5-fluorouracil (5-FU). Genetic variations in DPYD are predictive biomarkers of 5-FU toxicity. One such biomarker, rs75017182 (the causal allele linked to the “HapB3” haplotype), has been suggested to promote alternative splicing of DPYD, leading to expression of an inactive proteoform. However, carriers of rs75017182 exhibit only moderately increased risk of 5-FU toxicity and modestly decreased ex vivo DPD activity compared to carriers of another well-studied splice variant, rs3918290 (*2A). We hypothesized that, unlike *2A, the rs75017182 variant does not cause obligate alternative splicing but instead promotes partial alternative splicing. To test this, we generated dual-fluorescent minigene reporter constructs containing either the G (wildtype) or C (variant) allele. In our minigene system, alternative splicing was elevated in cells transfected with C-containing vectors via flow cytometry, though levels were lower than those observed in a parallel *2A model. To investigate contributions of other variants in LD with rs75017182, we expanded the reporter to include additional relevant genomic regions. The analyses were complemented by the study of in vivo splicing in cells engineered to harbor various combinations of variants and in lymphoblastoid lines carrying specific genotype combinations. Overall, our findings demonstrate that rs75017182-C promotes only partial alternative splicing, eliciting a modest decrease in DPD activity and explaining its comparatively weak association with severe 5-FU toxicity. Additional variants in LD have a minimal impact on splicing and 5-FU sensitivity. Citation Format: Lauryn Allyn Hahn, Ryan Schwartz, Hannah Marie Krause, Lulu Jiang, Brianna Bembenek, Kelly Bouchonville, Steven M. Offer. Partial alternative splicing in carriers of DPYD rs75017182 explains modest association with severe 5-FU toxicity to 5-FU [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 3137.

Abstract 5-Fluorouracil (5-FU) is a widely prescribed chemotherapy for colorectal, breast, gastric, and head and neck cancers. The drug inhibits thymidylate synthase, blocking DNA synthesis and causing cytotoxic stress that halts tumor growth. However, patients carrying deleterious variants in DPYD, the gene encoding the rate-limiting enzyme in 5-FU metabolism (dihydropyrimidine dehydrogenase, DPD), can experience fatal toxicity due to impaired drug clearance and accumulation of 5-FU metabolites. Current pharmacogenetic screening guidelines in the U.S. recommend testing for few of the >2,000 nonsynonymous variants that have been reported for DPYD, leaving patients with rare, uncharacterized mutations at risk. To interpret expanded testing, however, a means to classify DPYD variants of unknown significance is needed. To address this, we developed MPACT-DPD, a random-forest-based classifier that accurately predicts the functional impact of DPYD missense variants. Our model was trained on in-vitro activity of 156 variants and leveraged a feature set of biochemical, evolutionary, and AlphaFold3-derived structural features. We optimized hyperparameters using ten-fold stratified cross-validation and evaluated model performance with Matthews correlation coefficient (MCC) to account for moderate class imbalance (7:3 neutral to deleterious). It achieved exceptional performance, with a Matthews correlation coeffient (MCC) of 0.906 and an accuracy of 95.1% on an independent validation set (n=43). Furthermore, a SHAP (SHapley Additive exPlanations)-based interpretability analysis revealed cofactor proximity and residue conservation as the key drivers of predictions. MPACT-DPD showed superior performance at variant classification against other tools, including a DPYD gene-specific variant classifier, and has the potential to expand pre-treatment genetic screening to improve the safety of personalized 5-FU-based chemotherapy. Citation Format: Lulu Jiang, Ryan Jonathan Swartz, Lauryn Allyn Hahn, Brianna Bembenek, Hannah Marie Krause, Kelly Bouchonville, Steven M. Offer. MPACT-DPD: An interpretable machine learning classifier for predicting the functional impact of DPYD missense variants [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 2712.

Background: Tranexamic acid (TXA) is widely used in craniosynostosis surgery to reduce blood loss. Although the efficacy of TXA administration has been documented in the literature, dosing in the perioperative setting is variable and without a standard protocol. The purpose of this study is to determine the efficacy of continuing TXA postoperatively for patients undergoing suturectomy for metopic or unicoronal synostosis. Methods: We conducted a retrospective cohort study evaluating the use of postoperative TXA infusion in patients undergoing suturectomy for metopic and unicoronal craniosynostosis. All patients received a TXA bolus of 10 mg/kg at the time of surgical prep, followed by a TXA infusion at 5 mg/kg/hour during the procedure. Patients undergoing suturectomy for metopic or unicoronal synostosis in 2020 to 2021 received postoperative TXA infusion at 5 mg/kg/hour for the first 4 hours after surgery. Following a protocol change in anemia management at the institution in 2022, patients undergoing this surgery in 2022 did not receive a postoperative TXA infusion. Chart review was performed, and mean hemoglobin values were compared between patients who received postoperative TXA and those who did not, with analyses stratified by suture involvement to determine the impact of the protocol change. Results: Twenty-eight patients met the inclusion criteria: 14 patients received postoperative TXA, and 14 patients did not. Both groups included 8 patients undergoing metopic suturectomy and 6 patients undergoing unicoronal suturectomy. For patients who underwent metopic suturectomy and received postoperative TXA, the mean preoperative hemoglobin was 11.4 g/dL, and on postoperative day 1 (POD1) was 8.1 g/dL. For patients who underwent metopic suturectomy and did not receive postoperative TXA, the mean preoperative hemoglobin was 11 g/dL and on POD1 was 9.2 g/dL ( P =0.27). The differences in mean preoperative and postoperative hemoglobin were not statistically significant between the 2 cohorts, P =0.15 and P =0.20, respectively. For patients who underwent unicoronal suturectomy and received postoperative TXA, the mean preoperative hemoglobin was 12 g/dL, and on POD1 was 8.7 g/dL. For patients who underwent unicoronal suturectomy and did not receive postoperative TXA, the mean preoperative hemoglobin was 11.4 g/dL and on POD1 was 9.1 g/dL ( P =0.36). The mean preoperative and postoperative hemoglobin were not statistically different between the 2 cohorts, P =0.42 and P =0.92, respectively. Hospital length of stay averaged 1 day across both cohorts. No patient received a postoperative blood transfusion. Conclusion: In patients undergoing suturectomy for metopic or unicoronal craniosynostosis, postoperative TXA infusion made no significant difference in postoperative hemoglobin levels, length of stay, or postoperative transfusion. Discontinuing postoperative TXA could potentially decrease monitoring needs and lower hospital costs.

The underlying immunopathogenesis of inflammatory arthritis (IA) immune-related adverse event (irAE) remains obscure. Unlike rheumatoid arthritis (RA), where autoantibodies and B cell dysfunction are central features, the contribution of humoral immunity to IA-irAE is unclear. Here, we performed immunophenotyping of peripheral blood from patients with IA-irAE and compared them with patients with seronegative RA, immune checkpoint inhibition–treated patients without irAE, and healthy controls. IA-irAE was marked with increased cytotoxic gene expression and metabolic activation in T cells and reduced CXCR3 and CCR6 expression in CD4 + T cells. Contrary to seronegative RA, patients with IA-irAE displayed no substantial elevation in autoantibody levels or atypical CD11c + CD21 − B cells. IA-irAE was further characterized by elevated levels of interleukin-6 (IL-6), IL-12, and type I interferon, which correlated with the T cell activation phenotypes. Together, our findings define IA-irAE as a disease with certain immunological features distinctive from RA, representing a potentially T cell–driven, autoantibody-independent autoimmunity. These results offer insights into immune tolerance breakdown and therapeutic targeting in irAEs.

Emerging research suggests a potential role for glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in alcohol use disorder (AUD), because GLP-1 receptors are present in the brain regions involved in dopamine signaling and the human reward system. We present the case of a man prescribed GLP-1 RAs for obesity who had concomitant AUD. A 34-year-old man was referred to a family medicine clinic for medication therapy management of obesity. His medical history was notable for bipolar disorder, class 2 obesity, and obstructive sleep apnea (OSA). His Alcohol Use Disorders Identification Test score indicated high-risk alcohol use. Over the course of 10 months using an injectable GLP-1 RA (semaglutide), the patient showed a clinically significant decrease in both body weight and alcohol consumption. Although this patient initially sought care for weight loss goals to improve quality of life and symptoms of OSA, after 10 months of treatment with semaglutide he reported a considerable decrease in alcohol consumption leading to mental, social, and home life improvements. Our aim in presenting this case is to illustrate the potential benefit of GLP-1 RAs for decreasing alcohol consumption levels in a patient with multiple comorbid conditions. The case adds to the growing body of evidence supporting the exploration of GLP-1 RAs for the treatment of AUD. Additionally, it underscores the need to enhance AUD screening efforts within family medicine clinics to identify high-risk persons and provide timely interventions.

ABSTRACT Purpose Malignant rhabdoid tumor of the kidney (MRTK) is a rare, aggressive tumor seen in young children. The optimal timing of resection for locally advanced tumors is not well‐defined. The purpose of this study is to evaluate modern oncologic outcomes and the impact of surgical timing. Methods A multicenter retrospective review was performed by institutions participating in the Pediatric Surgical Oncology Research Collaborative. Children younger than 21 years old with MRTK diagnosed between 2000 and 2022 were included. Results Sixty‐nine patients were identified with MRTK and met the inclusion criteria. Median age of diagnosis was 10.1 months. Overall survival (OS) at 1, 5, and 10 years was 49%, 32%, and 19%, respectively. Patients with local Stage III disease who underwent upfront resection ( n = 18) compared to those who had delayed resection after NAT ( n = 15) had a similar OS, median OS greater than 60 months versus 14.6 months, respectively; p = 0.396. The surgical timing groups were balanced in terms of the presence of metastasis, length of follow‐up, and tumor characteristics. There was one occurrence of primary intraoperative tumor spill and two occurrences of organ injury in the upfront resection group compared to none in the delayed resection group. Conclusion MRTK carries a poor prognosis despite multimodal treatment. Histologic diagnosis may not be confirmed at presentation, and MRTK cannot be reliably distinguished from Wilms tumor on imaging alone. As overall survival is similar, the decision regarding surgical timing in locally advanced tumors should be individualized based on perceived resectability, balancing the risk of intraoperative complications against the possibility of tumor progression during neoadjuvant therapy.

Study Design. Finite element (FE) analysis of retrospective clinical cohort. Objective. To determine whether preoperative CT-derived FE model outputs can improve subsidence prediction compared with conventional clinical measurements alone in patients undergoing transforaminal lumbar interbody fusion (TLIF). Summary of Background Data. Cage subsidence occurs in ∼20% of spinal fusion patients and can lead to complications requiring reoperation. While individual risk factors are known, no validated tool integrates patient anatomy, bone quality, and implant characteristics to predict subsidence. Finite element models have been hypothesized to predict subsidence but lack clinical validation. Materials and Methods. Patient-specific FE models were created from preoperative CT scans of 42 TLIF patients: N=22 severe subsidence (≥4 mm); N=20 nonsevere subsidence (<4 mm). Vertebral geometries were segmented, and bone material properties were assigned based on Hounsfield units (HU). Cage positions from postoperative scans were registered to preoperative anatomy. Endplate and trabecular stresses and strains from FE models were compared with clinical measures using receiver operating characteristic analysis. Results. Fifteen principal stresses and strains of the FE simulations showed significantly higher values in severely subsided patients compared with the nonsevere group. Average trabecular intermediate strain achieved the highest area under the curve score (AUC=0.809), outperforming all clinical metrics. Peak endplate minimum principal stress (AUC=0.775) was the second-best FE classifier. Traditional clinical measures showed lower discriminative ability: cage length (AUC=0.797), cage width (AUC=0.750), and cage height (AUC=0.698). Conclusion. Patient-specific FE model outputs significantly correlate with clinical subsidence outcomes and outperform several traditional metrics in classifying severe subsidence. Both endplate and trabecular stresses and strains are important predictors, with average values showing comparable or superior performance to peak values. Integration of FE models into the clinical workflow could provide a comprehensive preoperative subsidence prediction tool.

Study Design: Retrospective cohort. Objective: This study aims to assess the effects of CT-based subsidence on lumbar sagittal alignment and patient-reported outcome measures (PROMs) after transforaminal lumbar interbody fusion (TLIF), and to determine if subsidence and cage properties are independent predictors of postoperative changes in regional lordosis. Summary of Background Data: Subsidence is a well-known complication following interbody fusion and has previously been associated with recurrence of preoperative symptoms and higher reoperation rates. There is incomplete evidence to characterize the effects of subsidence on lumbar alignment and PROMs following TLIF. Methods: All adult patients who underwent 1- or 2-level TLIF at a multi-institutional academic center between 2017 and 2019 were retrospectively identified. Interbody subsidence at the superior and inferior endplate of each TLIF level was directly measured on both coronal and sagittal CT scans obtained between 6 months and 1 year postoperatively. Patients were grouped based on the maximum subsidence at each operative level: mild-moderate (<4 mm) or severe (≥4 mm). Preoperative, immediate (<3 mo), and intermediate (>6 mo) postoperative radiographic outcomes (local and global lumbar alignment) and PROMs (VAS Back, Oswestry Disability Index, PROMIS Physical Function and Mood) were collected. Univariate and multivariate analysis compared patient demographics, surgical factors, and changes in radiographic measures and PROMs across subsidence groups. Multiple linear regression analyzed independent effects of subsidence and cage characteristics on alignment. Results: Sixty-seven patients with 85 unique fusion levels were included (55 with mild-moderate subsidence, 30 with severe subsidence). Levels with severe subsidence demonstrated significantly less regional lordosis at final follow-up than nonseverely subsided levels (6.4 vs. 9.1 degrees, P =0.032). No PROM significantly differed between severe and nonsevere subsidence subgroups. Linear regression analysis revealed that severe subsidence was a strong independent predictor of regional lordosis ( P =0.029) at final follow-up. Conclusions: Severe subsidence negates perioperative improvements in regional lordosis following TLIF, while changes in regional alignment are maintained in the absence of severe subsidence. Level of Evidence: Level III.