Citations

Abstract Background Breast cancer (BC) diagnosed during pregnancy or postpartum often presents with aggressive features, potentially influenced by hormonal, immunological, and tissue remodeling changes. Studies have suggested that postpartum BC may be associated with worse outcomes, though most evidence is retrospective and constrained by methodological limitations. This study evaluated associations between pregnancy history, recency of childbirth, and long-term outcomes in a prospective cohort of young patients with early-stage BC. Patients and Methods Patients aged ≤40 years with stage I–III BC enrolled in the Young Women’s Breast Cancer Study were categorized at diagnosis as nulligravid, nulliparous, pregnant, or parous (≤5 vs 5 to 10 years postpartum). Analyses were stratified by BC subtype (estrogen receptor-positive [ER+]/HER2−, HER2+, and triple-negative [TNBC]), with distant recurrence-free survival (DRFS) as the primary endpoint. Results Among 859 patients, 257 (29.9%) were nulligravid, 50 (5.8%) nulliparous, 37 (4.3%) pregnant, and 515 (60.0%) parous. Pregnant patients had proportionally more TNBC, nodal involvement, T3/T4, and grade 3 tumors. After 11.1 years median follow-up, pregnancy or postpartum status was not independently associated with DRFS in multivariable models adjusted for age, tumor characteristics, and treatment, with consistent findings across ER+/HER2−, HER2+, and TNBC subtypes. Sensitivity analyses, including further categorization of postpartum diagnoses (<2 vs 2 to 5 years), yielded consistent results. Conclusions Pregnancy history and recency of childbirth were not independently associated with long-term DRFS. Despite more aggressive features at diagnosis, patients diagnosed during or after pregnancy had comparable outcomes after adjustment, suggesting no adverse prognostic impact. Clinical trial registration NCT01468246 (https://clinicaltrials.gov/study/NCT01468246? term=NCT01468246&rank=1).

Background: Spasticity after upper motor neuron injury (stroke, spinal cord injury, etc.) alters muscle activity and induces long-term structural remodeling of skeletal muscle [1]. Elbow flexors, including the biceps brachii, are frequently affected, leading to abnormal tone, involuntary co-contraction, and impaired elbow function. Hyper-selective neurectomy (HSN) is a well-established surgical technique that has gained renewed clinical adoption with advances in anatomic understanding and intraoperative nerve mapping [2], yet its effects on muscle properties are poorly defined. Objective: The purpose of this study was to define pre- vs. post-HSN differences in muscle gene expression, sarcomere length, and clinical outcomes of the spastic human biceps. Methods: Individuals with elbow flexor spasticity undergoing a planned two-stage HSN were prospectively enrolled (n=10). Stage 1 released the elbow flexors and provided a pre-biopsy; Stage 2, performed ~3 months later to treat the forearm flexors, provided a second exposure to the biceps and a second biopsy. In both stages, biceps biopsies were obtained with customized clamps [3] at predefined elbow angles (50°, 90°, 135°), fixed, and analyzed for sarcomere length [4]. Total RNA was extracted from pre- and post-HSN biceps samples to characterize transcriptional changes. Clinical spasticity was assessed before Stage 1 and again before Stage 2 using the Modified Ashworth Scale (MAS). Data were compared using repeated-measures models, and single-cell transcriptional changes were analyzed using established analytical pipelines. Results: Sarcomere length (SL) increased significantly after HSN at all joint angles. At 50°, SL increased from 2.45 ± 0.18 µm pre-HSN to 3.05 ± 0.28 µm post-HSN; at 90°, from 2.70 ± 0.29 µm to 2.91 ± 0.16 µm; and at 135°, from 2.72 ± 0.36 µm to 3.24 ± 0.32 µm (all p < 0.05). Clinical spasticity assessment improved significantly as well (p < 0.05), with MAS scores decreasing from 1.89± 0.93 to 0.35 ± 0.53. RNA sequencing revealed changes in key pathways and overall gene expression patterns such as enhanced inflammatory response through increased cytokine production and fibroblast proliferation, leading to elevated collagen synthesis and subsequent fibrosis. We also observed upregulated immune modulation and chemotaxis, while pathways involved in mitochondrial respiration, muscle development, and cellular homeostasis were downregulated. At the transcript level, HSN led to decreased inflammation and adipogenesis, while promoting increased extracellular matrix assembly, and vascular formation. Conclusion: HSN produced coordinated improvements across structural, clinical, and transcriptional levels in the spastic human biceps muscle. Sarcomere lengths increased toward longer resting lengths at all joint angles, clinical spasticity decreased significantly, and RNA sequencing revealed distinct post-operative transcriptional remodeling. The longer sarcomere length and decreased spasticity should contribute to improved patient function after HSN. References: 1. Lieber RL et al. Muscle Nerve. 2002;26:98–105. 2. Leclercq C et al. Hand Clin. 2018;34:537–545. 3. Lieber RL et al. J Neurophysiol. 1994;71:874–881. 4. Ward SR et al. J Biomech. 2009;42:193–196. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

BACKGROUND: Free fibula flaps have been widely used for bony reconstruction in pediatric patients. While donor site complications have been well studied in adults, data in the pediatric population remains limited. This study exclusively reports donor-site morbidity following fibula flap harvests in the pediatric and adolescent population. METHODS: We reviewed all patients younger than 18 years with open physes who underwent fibula flap harvests at a single academic institution from 1997 to 2024. Demographics, clinical and surgical characteristics, and donor-site complications were recorded. RESULTS: Fifty-seven free fibula flaps were harvested from 55 pediatric patients (mean age 12 years; 29 female) with a mean follow-up of 6 years. Flaps were most commonly used for lower extremity reconstruction (52%) and following tumor resection (74%). Osteoarticular flaps (n=8) were associated with transient deep peroneal nerve palsy in four cases, all of which recovered antigravity dorsiflexion by 6 months. In standard segmental harvests (n=49), donor-site complications occurred in 38%, most frequently valgus ankle deformity (9%) and neuropathic pain (6%). Valgus deformity was more likely in patients with shorter distal residual fibula and an age–residual fibula index (A-RFI) <16. CONCLUSIONS: Vascularized fibula flaps are safe and versatile for pediatric skeletal reconstruction. Donor-site complications are common but generally manageable, with full recovery of nerve function. Osteoarticular harvests carry the highest risk of peroneal nerve injury, and valgus ankle deformity may occur, particularly with an age–residual fibula index <16. Careful planning and age-adjusted fibular preservation are essential to optimize outcomes.

Summary Cancer genome sequencing is essential for understanding tumor evolution and advancing precision medicine. 1 However, reference gaps and germline variants obscure detection of small and large somatic variants and methylation in repetitive regions. 1–3 It is common for tumor cells to gain or lose chromosome arms due to somatic structural changes that occur inside highly repetitive satellite DNA sequences in the centromeres. 4 To identify the full spectrum of somatic variants, including complex rearrangements, we construct and curate near-complete, haplotype-resolved assemblies of the most recent common ancestor of an early-passage broadly-consented hypodiploid pancreatic cancer cell line and matched normal tissues. The tumor assembly completely recapitulates all 35 tumor chromosomes observed with karyotyping, with multiple translocation-induced hybrid chromosomes. The hybrid chromosomes contain putative functional dicentric and fused centromeres, nested foldback inversions causing 14 breakpoints with a haplotype switch in a single event, and centromeric satellite tandem duplications up to 136 kbp. Direct comparison of tumor and normal assembly haplotypes uncovers >7,000 variants altering >1 Mbp of sequence in repetitive regions that have been hidden by reference gaps and germline variants. 44 % of somatic small variants change representation because they alter germline variants on GRCh38, impacting mutational signatures and kataegis/omikli clusters. Most somatic LINE insertions originate from two hypomethylated non-reference germline LINE insertions, highlighting their impact on insertion mutation burden. These assemblies demonstrate that centromeric, acrocentric, and telomeric regions conventionally excluded from analysis harbor extensive somatic and epigenetic changes. Resolving complete tumor genomes enables a deeper understanding of cancer structural plasticity and the endpoints of breakage-fusion-bridge cycles. These assembled, curated paired normal-tumor benchmarks will serve as a critical foundation for developing future algorithms to characterize the most intractable regions of cancer genomes.

RELA-related disease is a rare, autosomal-dominant condition presenting with immune dysregulation and immunodeficiency. RELA encodes the p65 subunit, a component of the canonical NFκB pathway. The underlying pathogenesis, at least in part, involves impaired NFκB activation, increased susceptibility to TNFα-induced apoptosis, and hyperinflammation. To date, only a modest number of cases have been documented worldwide, and the full clinical and functional spectrum of disease remains incompletely defined. This study represents a large global cohort identified with RELA variants, comprising 40 patients from 30 institutions, expanding our previous report of a single large kindred (1). The clinical spectrum includes arthritis, mucocutaneous ulcers, uveitis, dermatitis, irritable bowel disease, recurrent infections, lymphopenia, hypogammaglobulinemia, recurrent fevers, and susceptibility to neoplasia. The patients represent 36 kindreds with 28 unique RELA variants, of which 15 are missense, 7 nonsense, and 6 frameshift variants. Fifteen are in the Rel homology domain, 7 in the transcriptional activation domain, and 6 in the C-terminal region proximal to TAD (Fig. 1). Functional studies assessed the canonical NFκB pathway in 27% of the cohort (n = 11; healthy controls = 40). Patient peripheral blood mononuclear cells (PBMCs) were used to quantify total and phosphorylated p65 (ph-p65, Ser529) by flow cytometry after stimulation with PMA (100 ng/ml) and ionomycin (1 uM). In 8 patients, we assessed the kinetics of IκBα degradation, required for p65 phosphorylation and nuclear translocation of p65/p50. All patients tested had decreased total p65, while 64% had decreased ph-p65 with altered phosphorylation kinetics. Nearly 45% had impaired IκBα degradation. One patient (P4) demonstrated increased IκBα degradation and ph-p65, while a related proband (P1) had decreased ph-p65. Additionally, P4 did not have the same mucocutaneous clinical phenotype as P1 despite sharing the same RELA variant. This could reflect the effect of other genetic modifiers, epigenetic, environmental, or stochastic variations, which could lead to variable expressivity and/or incomplete penetrance. All patients appeared to have haploinsufficiency, as none had normal levels of p65. This study expands the clinical and genetic spectrum of RELA-related disease and provides mechanistic insights into the impact of these variants on p65 phosphorylation and downstream function, resulting in variable expressivity. Figure 1. RelA protein structure. Represents unique variant locations and categories, key domains, and phosphorylation sites. Source: UniProt. Adapted from (2). BioRender.

INTRODUCTION: Nosocomial infections (NIs) in cirrhosis are associated with high mortality but could be preventable. Logistic regression (LR) models have failed to identify high-risk patients. We aimed to develop machine learning (ML) models to predict NI. METHODS: The CLEARED consortium consists of prospectively enrolled cirrhosis inpatients from >120 centers. Using day-of-admission clinical data, 3 ML approaches (random forest [RF], extreme gradient boosting, and neural networks [NNs]) were used to predict NI. Data were split 80:20 for training and testing stratified by the outcome. Models were compared using area under the receiver operating characteristic curve (AUC). RESULTS: In total, 8,263 patients (55.90 ± 13.34 years; 64.1% men) from 127 centers in 37 countries were included. NI developed in 869 (10.5%), a median of 6 (4–11) days of postadmission. Major NIs were respiratory (29.6%) and urinary tract infection (15.7%), and spontaneous bacterial peritonitis (13.5%). NIs occurred more frequently in patients from low/low-middle income countries and those with severe liver disease, alcohol etiology, and admission infections. NIs were associated with inpatient mortality (31.9% vs 8.1%, P < 0.001) and liver transplantation (4.8% vs 1.9%, P < 0.001). Although the RF model (AUC 0.69) showed good calibration (Brier score 0.09), outperforming extreme gradient boosting, neural network, and LR models (AUC 0.66 for all; LR comparison P = 0.043), no model achieved AUC ≥0.80 for clinical utility. At 10% predicted probability threshold, the RF model demonstrated only 75.4% sensitivity, 52.9% specificity, and 15.9% positive predictive value (PPV). DISCUSSION: NIs cannot be accurately predicted from day-of-admission data using ML models, even in a large, prospective, global cirrhosis cohort. Every hospitalized patient with cirrhosis should receive protocolized infection control measures.

Abstract Pancreatic cancer disproportionately affects Black individuals in the United States, but they have limited representation in genetic studies of pancreatic ductal adenocarcinoma (PDAC). To address this gap, we performed admixture mapping and genome-wide association analysis (GWAS) in genetically inferred African ancestry individuals (1,030 cases and 889 controls). Admixture mapping identified three regions with a significantly higher proportion of African ancestry in cases compared to controls (5q33.3, 10p1, 22q12.3). GWAS identified a genome-wide significant association at 5p15.33 ( CLPTM1L , rs383009:T>C, T Allele Frequency=0.51, OR:1.45, P value=1.24×10 -8 ), a locus previously associated with PDAC. Known loci at 5p15.33, 7q32.3, 8q24.21 and 7q25.1 also replicated (P value <0.01). Multi-ancestral fine-mapping identified two potential causal SNPs (rs3830069 and rs2735940) at 5p15.33. Collectively these findings identified novel PDAC risk loci and expanded our understanding of this deadly cancer in underrepresented populations, emphasizing the multifactorial nature of PDAC risk including inherited genetic and non-genetic factors. Statement of Significance To understand how genetic variation contributes to PDAC risk in Black people in North American, we studied individuals of genetically-inferred African ancestry. We identified novel risk loci and differences in the contribution of known loci. This demonstrates that ancestry-informed genetic analyses improve our understanding of PDAC risk and enhances discovery.

Abstract Background Atypical hemolytic uremic syndrome (aHUS) is a rare, complement-mediated disorder. Disease-associated variants have been found in complement factor H-related genes and complement regulatory genes. Particularly, homozygous deletions of CFHR1, CFHR3, or CFHR4 have been associated with aHUS. Generally, multiplex ligation-dependent probe amplification (MLPA) is used to detect copy number changes in the CFH and CFHR regions. We have developed a cost-effective droplet digital PCR (ddPCR) method for measuring copy number variations (CNVs) in these genes. Methods A total of 41 DNA samples were analyzed using both ddPCR and MLPA to assess large deletions in the CFHR1, CFHR3, CFHR4 regions. The ddPCR primers were designed to avoid rare single nucleotide polymorphisms to enhance hybridization efficiency and accurate identification of deletions within the CFHR regions. The MLPA probe mix (Probemix P236 CFH Region) targeting CFHR regions was purchased from MRC Holland. Results Multiple heterozygous deletions were observed in the CFHR1, CFHR3, and CFHR4 genes. Homozygous deletions of CFHR1 and CFHR3 were seen in 2 cases, while 2 other cases showed homozygous CFHR1 and heterozygous CFHR3 deletions. All 41 samples demonstrated 100% concordance in copy number results between ddPCR and MLPA, as well as consistent reproducibility in both inter- and intratechnologist evaluations. Conclusions Our findings demonstrate that ddPCR is a robust platform to identify large deletions in the CFHR regions. Future studies are needed to evaluate its ability to distinguish full vs partial deletions and to further establish its clinical diagnostic value.