Citations

Abstract Introduction Mediastinal masses may exhibit various clinical and pathological features. Posterior mediastinal lesions are often neurogenic, followed by lymphadenopathy, extramedullary hematopoiesis, paraspinal abscess, and rarely, foregut duplication cysts (prevalence: 0.122%). Given the rarity and diagnostic challenges, these masses are often biopsied, though may not be ideal. We present a case of esophageal duplication cyst (EDC). Case presentation A 33-year-old woman with mild intermittent asthma, had initially presented to an outside facility for chronic productive cough, episodic chest tightness and dyspnea both at rest and with exertion, inspiratory and expiratory wheezes. Despite multiple courses of prednisone for presumed asthma exacerbation, her symptoms persisted. An initial Computer Tomography (CT) Chest demonstrated a 5 x 4 x 3 cm mass within the visceral mediastinum. Bronchoscopy with endobronchial ultrasound and transbronchial needle aspiration of the mediastinal lymph nodes was nondiagnostic, showing scant lymphocytes and abundant mucin. Broad autoimmune, connective tissue disease, and infectious disease workups were negative, prompting referral to our facility. Physical exam and labs were unremarkable and pulmonary function testing showed no evidence of small airway obstruction. A High-Resolution CT Chest revealed a 3.1 x 3.7 x 4.5 cm noncalcified, well-circumscribed mass soft tissue density, adjacent to the esophagus with elevated Hounsfield units close to esophagus. Ultimately duplication cyst was suspected and Magnetic Resonance Imaging (MRI) with contrast showed high T1 and T2 signal within the lesion and no enhancement after contrast, deemed compatible with proteinaceous/hemorrhagic cyst (Figure 1 A-D). Biopsy was deferred given diagnostic MRI characteristics, and risk of secondary infection. The diagnosis of EDC was confirmed via multidisciplinary thoracic tumor board revision. Ultimately, she was referred for surgical resection. Discussion The incidence of EDC is 1 in 8,200, with a two-fold male prevalence over women. These patients may present with dysphagia, cough, stridor, pain, or arrhythmia since childhood, or may be entirely asymptomatic. EDCs can develop along the esophagus, with 90% lacking communication with the esophageal lumen. Although posterior mediastinal mass typically require biopsy to exclude malignancy, tissue biopsy should be avoided in cases with suspected duplication cyst given risk of infection, abscess formation and mediastinitis. Transesophageal endoscopic ultrasonography could further characterize the cyst, however MRI is considered the gold standard diagnostic modality. Conclusion MRI is the gold standard diagnostic modality of EDC. Biopsy should be avoided given the risk of infection. Clinicians should consider a broad differential for posterior mediastinal mass and avoid unnecessary invasive testing.

Abstract Introduction Unilateral pulmonary vein atresia (UPVA) is a rare congenital anomaly involving absent or obstructed pulmonary veins (PV), often leading to chronic pulmonary venous stasis, recurrent infections, and hemoptysis. Although typically diagnosed in infancy, UPVA can present in adulthood. This report presents a 63-year-old male referred as a case of chronic thromboembolic pulmonary disease (CTEPD) who was diagnosed with UPVA. We describe the diagnostic complexities and potential explanation for loss of pulmonary artery (PA) perfusion in such cases. Case Presentation A 63-year-old man was referred to rule out CTEPD. His past medical history included coronary artery disease and sleep apnea. He presented with chronic cough, repeated hemoptysis, recurrent pneumonias requiring prolonged antibiotics use, and progressive exertional dyspnea. Physical examination was unremarkable. Pulmonary function tests showed moderate restriction and moderately-reduced diffusion capacity. A ventilation-perfusion (V/Q) scan revealed complete absence of perfusion in the left lung. [figure1] High-resolution CT revealed a straight left atrial border sign with absent left superior and inferior PVs, left pulmonary arterial tree hypoplasia, hypoplastic left lung with fibrotic changes due to chronic venous-lymphatic engorgement and pulmonary hypoperfusion. CT also showed compensatory right lung hyperinflation and bronchial artery collaterals. Echocardiography indicated an atrial septal defect (ASD) with no pulmonary vascular disease. Based on CT angiography, UPVA was considered the leading diagnosis. Discussion UPVA is a congenital disease rarely presenting in adulthood with recurrent infections, hemoptysis, and fibrosis. It often accompanies congenital cardiac conditions, like ASD in our case. Pulmonary angiography may reveal ipsilateral PA hypoplasia and atrophied peripheral vessels. The absence of perfusion in the V/Q scan could be explained by reversed blood flow in the PA from congestion caused by the atretic PVs and ipsilateral backflow from the bronchial arteries collaterals. Differential diagnosis like CTEPD was excluded due to atypical complete loss of perfusion of the left lung, and lack of the other radiological stigmata. Swyer-James-MacLeod syndrome was excluded due to a mismatched perfusion defect. Proximal Interruption of the PA was also excluded due to normally developed proximal left and right PAs. Imaging is crucial in showing absent PVs and hypoplastic ipsilateral lung. Conservative management for UPVA is recommended. Given recurrent infections and hemoptysis, pneumonectomy can be considered. Conclusion This case illustrates the atypical presentation of UPVA as a CTEPD mimicker, presenting with absent pulmonary perfusion unilaterally, which can be explained by reversed pulmonary flow secondary to venous engorgement and backflow from bronchial artery collaterals. Figure1:

Abstract Breast cancer is the leading cause of cancer death among women worldwide. Most cases occur in those without identifiable modifiable risk factors, highlighting critical gaps in our understanding of breast cancer biology including the influence of the gut microbiome. Here we studied the gut microbiome with shallow shotgun metagenomic sequencing from preoperative stool samples in a well-characterized clinical cohort of 131 women, median age 59 years, undergoing breast-conserving surgery for benign (n=23), high-risk (n=47), or malignant (n=61) breast disease. Taxonomic profiling was performed with Sourmasth 4.2.4 with GTDBv202 as reference database; functional profiling of metagenomic data employed HUMAnN 3.6 with identified gene families mapped to MetaCyc pathways. Differences in alpha diversity in terms of species richness were observed across diagnosis groups (benign, high-risk, malignant) and was lowest for high-risk lesions (p=0.031). Decreased alpha diversity was also associated with higher body mass index (BMI) (Shannon p=0.12, Inverse Simpson p=0.025). Significant beta diversity differences across diagnosis groups also were seen (Bray-Curtis p=0.044, Jaccard p=0.013) as were differences in association with BMI (Bray-Curtis, Jaccard, both p=0.002). No significant diversity differences associated with age, mammographic breast density or menopausal status were observed. Functional pathway profiling stratified by BMI showed a correlation between increasing BMI and greater relative abundance of genes in nicotinamide adenine dinucleotide (NAD) biosynthesis, folate metabolism, and aromatic amino acid metabolism pathways (p=0.0279, 0.0667 and 0.0860, respectively) - pathways implicated in breast cancer detection, survival and prognosis. Cross-referencing our significantly (FDR <5%) differentially abundant taxonomic findings with these functional pathway data identified enrichment of several Blautia species, linked to NAD biosynthesis via tryptophan metabolism, in patients with higher BMI. We also noted enrichment of Dorea formicigenerans, a species associated with increased breast cancer risk in obese women due to its pro-inflammatory effects, in individuals with a higher BMI. Here we report significant differences in gut microbiome diversity, taxonomy and functional pathway signals in association with BMI in women with breast disease. Differentially abundant species seen with rising BMI may contribute to functional pathways that drive increased breast cancer risk and may provide an actionable target for risk reduction independent of conventional risk reduction strategies. Citation Format: Jack W. Sample, Matteo Redaelli, Stephen Johnson, Tanya L. Hoskin, Marina R. Walther-Antonio, Jun Chen, Tina J. Hieken. Obesity alters cancer-related microbial pathways in women with benign and malignant breast disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2213.

Background Neoadjuvant treatment has become standard for patients with high-risk operable stage III melanoma, but the optimal regimen is unknown. Targeted therapy approaches yield high pathological response rates, while immunotherapy regimens show favorable recurrence-free survival (RFS). NeoACTIVATE was designed to address whether a neoadjuvant combination of both targeted therapy and immunotherapy might leverage the benefits of each. Methods We tested neoadjuvant treatment with 12 weeks of vemurafenib, cobimetinib, and atezolizumab for patients with BRAF-mutated (BRAFm) melanoma (cohort A) and cobimetinib and atezolizumab for patients with BRAF-wild-type (BRAFwt) melanoma (cohort B), regimens which we have shown generate a substantial major pathological response. After therapeutic lymph node dissection, patients received 24 weeks of adjuvant atezolizumab. Here, we report survival outcomes and their association with biomarkers assayed among the gut microbiome and peripheral blood immune subsets. Results With 49 months median follow-up, the median RFS was not reached for cohort A and was 40.8 months for cohort B. At 24 months after operation, 2 of 14 cohort A patients and 4 of 13 cohort B patients had experienced distant relapse. Key findings from correlative analyses included diversity, taxonomic and functional metagenomic gut microbiome signals associated with distant metastasis-free survival at 2 years. Notably, we observed a strong correlation between low microbial arginine biosynthesis (required for T-cell activation and effector function) and early distant recurrence (p=0.0005), which correlated with taxonomic differential abundance findings. Peripheral blood immune monitoring revealed increased double-positive (CD4+CD8+) T cells in patients with early recurrence. Conclusions Neoadjuvant treatment with cobimetinib and atezolizumab±vemurafenib was associated with a low rate of distant metastasis in patients with high-risk stage III melanoma. Freedom from early distant metastasis was highly associated with taxonomic differences in gut microbiome structure and with functional pathway alterations known to modulate T cell immunity. Identification of predictive biomarkers will permit optimization of neoadjuvant therapy regimens for individual patients. Trial registration number NCT03554083.

Objectives/Goals: Longitudinal studies capture dynamic host–environment interactions crucial to microbiome research. Commonly used mixed-effects models can struggle with small clinical samples, like many endometrial cancer studies. We will compare them to simpler fixed-effects models, aiming to develop a new fixed-effects differential abundance alternative. Methods/Study Population: Starting with simulated data for linear models with a single treatment effect, we will incrementally increase complexity to reflect real-world microbiome data. To observe conditions of misspecification, simulated data of repeated measures will be generated using different distributions, while varying parameters and inter-class correlation. In each condition, linear fixed- and mixed-effects models will be fitted 1000 times to empirically determine p-value, type 1 error rate, and power. We will increase the verisimilitude of our approach by using endometrial cancer data from our lab as a real background, while adding simulated signals. This data will be used to assess extant differential abundance models against our novel fixed-effects model. Results/Anticipated Results: Our initial findings indicate that fixed-effects models maintain control over type 1 error rates in small samples, while mixed-effects models do not perform as reliably. We are now exploring the effects of confounders on type 1 error rates and power in linear models, while our next step will evaluate generalized linear models in a differential abundance context. We expect that the fixed-effects models will continue to be as reliable as mixed-effects models, while being less computationally complex. After establishing our theoretical basis, our novel model should perform comparably to mixed-effects models on pseudo-simulated endometrial cancer data and better at small sample sizes. We will finally apply our model to real endometrial cancer data to identify microbial markers of disease predisposition. Discussion/Significance of Impact: By characterizing and improving these statistical tools, we seek to increase the robustness and power of microbiome study results (especially at small sample sizes), ultimately supporting better-informed translational research decisions. This work underscores the importance of statistical methods in advancing microbiome research.

Abstract Purpose To evaluate the test–retest repeatability of a rapid, free‐breathing two‐dimensional (2D) MR elastography (MRE) technique and to assess the reliability of the liver‐stiffness measurements compared with conventional breath‐hold MREs. Methods Fifteen and 115 participants were enrolled in the technical repeatability and measurement equivalence assessment cohorts, respectively. All participants underwent rapid free‐breathing and conventional breath‐hold 2D MRE (twice in repeatability cohort) on 1.5T scanners. Both methods have four phase offsets over one harmonic motion cycle at 60 Hz; one and 10 cycles were collected and processed in breath‐hold and free‐breathing MREs, respectively. The liver stiffness measurements of free‐breathing (LS F ) and breath‐hold MRE (LS B ) were calculated from manually drawn regions of interest. The repeatability coefficients and Spearman correlation were used to assess technical repeatability and measurement agreement between LS F and LS B . Univariable and multivariable linear regressions were performed to identify potential influencing factors, including age, sex, body mass index, and fat fraction, in the measurement agreement between LS B and LS F . Results The repeatability coefficient of free‐breathing 2D MRE is comparable to breath‐hold MRE (LS F : 20.8%, LS B : 20.4%). LS F showed a strong agreement and significant correlation with LS B (LS F = 1.01 × LS B , ρ = 0.94, p < 0.001). The measurement agreement between LS F and LS B was only significantly affected by sex ( p = 0.047) after adjusting for confounding factors of age, body mass index, and fat fraction. Conclusions The nongated, free‐breathing, multislice 2D MRE technique can provide reliable liver stiffness measurements compared with conventional breath‐hold 2D MRE. It could provide a comfortable alternative method with reliable liver stiffness measurements for patients who have difficulty in suspending respiration.

Abstract The prevalence of steatotic liver disease (SLD) is rising globally, presenting a significant public health challenge. While non-contrast computed tomography (CT) scans hold promise for the opportunistic detection of SLD, their full potential has not been systematically explored. Clinical indicators, such as serum data, are crucial for monitoring the progression of SLD. We introduce a novel Multimodal AI for Opportunistic Steatotic Liver Disease Screening (MAOSS), which integrates demographic data, serum tests, conventional CT biomarkers, and deep learning-derived CT image features to enhance model performance and explainability. MAOSS employs an innovative learning strategy, trained on a large-scale dataset (n = 1,783) encompassing both histopathologically-confirmed SLD and radiologically-reported steatosis cases. The model underwent extensive retrospective validation using steatosis grades derived from both histology and MRI-PDFF across internal and external datasets (n = 913), as well as real-world patient data (n = 18,504). It accurately detected mild to severe steatosis (≥ S1) with AUCs ranging from 0.903 to 0.929. Notably, MAOSS significantly improved the overall AUC for radiologists (n = 11) from 0.709 to 0.798 (p < 0.001). Furthermore, MAOSS was applied to optimize the standard clinical pathway for a simulated primary risk screening of SLD patients (n = 1,192), resulting in the identification of 31% more patients at risk of steatohepatitis and liver fibrosis progression, highlighting its potential to enhance SLD detection and management.

AbstractBackgroundThe efficacy of Calorie Restriction (CR) in enhancing cognition, promoting healthy aging, and extending lifespan is well‐established. Yet, it remains unclear whether the apolipoprotein E (APOE) genotype, a known modifier for aging and age‐related disorders, influences the beneficial effects of CR in countering aging.MethodsTo investigate this question, we utilized humanized APOE mouse models, which express APOE2, APOE3, or APOE4 alleles systematically (refer to as E2, E3, and E4 mice). These mice were subjected to either ad libitum (AL) feeding or 30% CR feeding, starting from 12 months and continuing up to 20 months of age (N = 11‐20/ genotype /group, mixed sex). We monitored energy expenditure using the Comprehensive Laboratory Animal Monitoring System (CLAMS). Additionally, we evaluated anxiety levels and memory capabilities through various behavioral tests. Finally, we collected brain, blood, and feces samples for transcriptomic, lipidomic, and microbiomic analyses.ResultsCLAMS measurements showed that CR significantly decreased the metabolic rate in E3 and E4 mice, but not E2 mice, during the non‐feeding period of the CR group, compared to the AL group. Furthermore, CR reduced anxiety and enhanced associative memory in E3 and E4 mice relative to the AL group. Brain transcriptomics revealed that CR upregulated the cholesterol synthesis pathway, potentially improving myelination‐related pathways in E3 and E4 mice. This finding was further validated by the increased staining intensity of myelin basic protein (MBP) observed in E3 and E4 mice from an independent cohort. In contrast, these effects were not pronounced in E2 mice. Additionally, while CR’s impact on the brain lipid profile was minor across all APOE genotypes, it significantly altered blood lipid profile of E2 mice, with minimal changes observed in E3 and E4 mice. Finally, in microbiomics, CR led to notable changes in the abundance of Bifidobacterium species in E3 and E4 mice and Lactobacillus species in E2 mice.ConclusionsOur study highlights the role of APOE genotypes in modulating the diverse effects of CR on cognition, brain transcriptomics, lipid metabolism, and the microbiome, providing a crucial foundation for considering APOE genotypes in developing prevention strategies for aging and age‐related disorders.

BackgroundMultiparametric MRI may cause overdiagnosis of clinically significant prostate cancer (csPCa) with the Prostate Imaging Reporting and Data System version 2.1 (PI‐RADS v2.1).ObjectivesTo investigate the diagnostic performance of stiffness as a standalone and complementary marker to PI‐RADS v2.1 for diagnosing csPCa.Study TypeProspective.SubjectsOne hundred forty‐seven participants with pathologically confirmed prostate lesions (≥1 cm), including 71 with csPCa.Field Strength/SequenceT1‐weighted fast spin‐echo, T2‐weighted fast spin‐echo, single‐shot echo‐planar diffusion‐weighted imaging, fast 3D gradient‐echo T1‐weighted dynamic contrast‐enhanced imaging, and 3D single‐shot spin‐echo based echo‐planar MR elastography at 3.0 T.AssessmentThe PI‐RADS v2.1 score was assessed by three radiologists independently. Lesion shear stiffness (SS) values at 60 Hz and 90 Hz were measured. A modified PI‐RADS integrating stiffness with PI‐RADS v2.1 was developed. Diagnostic performance for csPCa was compared between stiffness, PI‐RADS v2.1 and the modified PI‐RADS.Statistical TestSpearman's correlation, Fleiss κ and intraclass correlation, Pearson correlation, one‐way analysis of variance, area under the receiver operating characteristic curve (AUC), and the Delong test. Significance level was P < 0.05.ResultsIn the peripheral zone, csPCa (N = 35) had significantly higher SS than non‐csPCa at 60 Hz (3.22 ± 0.66 kPa vs. 2.56 ± 0.56 kPa) and at 90 Hz (5.64 ± 1.30 kPa vs. 4.48 ± 0.84 kPa). PI‐RADS v2.1 showed 100% sensitivity, 58% specificity, and 0.79 AUC for detecting csPCa. SS achieved 97% sensitivity, 52% specificity, and 0.80 AUC at 60 Hz, while SS had 63% sensitivity, 87% specificity, and 0.78 AUC at 90 Hz. The modified PI‐RADS, combing SS at 60 Hz with PI‐RADS v2.1, resulted in a significantly increased AUC (0.86) compared to that of PI‐RADS v2.1, with a sensitivity of 97% and specificity of 75%.Data ConclusionStiffness can help identifying csPCa in the peripheral zone. Combining stiffness with the PI‐RADS v2.1 improved the diagnostic accuracy and specificity for csPCa.Evidence Level1Technical EfficacyStage 2

Abstract Motivation Emerging omics technologies have introduced a two-way grouping structure in multiple testing, as seen in single-cell omics data, where the features can be grouped by either genes or cell types. Traditional multiple testing methods have limited ability to exploit such two-way grouping structure, leading to potential power loss. Results We propose a new 2D Group Benjamini–Hochberg (2dGBH) procedure to harness the two-way grouping structure in omics data, extending the traditional one-way adaptive GBH procedure. Using both simulated and real datasets, we show that 2dGBH effectively controls the false discovery rate across biologically relevant settings, and it is more powerful than the BH or q-value procedure and more robust than the one-way adaptive GBH procedure. Availability and implementation 2dGBH is available as an R package at: https://github.com/chloelulu/tdGBH. The analysis code and data are available at: https://github.com/chloelulu/tdGBH-paper.