Comprehensive performance evaluation of ligand-binding assay-LC-MS/MS method for co-dosed monoclonal anti-SARS-CoV-2 antibodies (AZD7442)

Aims: AZD7442 is a combination SARS-CoV-2 therapy comprising two co-dosed monoclonal antibodies. Materials & methods: The authors validated a hybrid ligand-binding assay-LC-MS/MS method for pharmacokinetic assessment of AZD7442 in human serum with nominal concentration range of each analyte of 0.300-30.0 μg/ml. Results: Validation results met current regulatory acceptance criteria. The validated method supported three clinical trials that spanned more than 17 months and ≥720 analytical runs (∼30,000 samples and ∼3000 incurred sample reanalyses per analyte). The data generated supported multiple health authority interactions, across the globe. AZD7442 (EVUSHELD) was approved in 12 countries for pre-exposure prophylaxis of COVID-19. Conclusion: The results reported here demonstrate the robust, high-throughput capability of the hybrid ligand-binding assay-LC-MS/MS approach being employed to support-next generation versions of EVUSHELD, AZD3152.

mtx-COBRA: Subcellular localization prediction for bacterial proteins

BACKGROUND

Bacteria can have beneficial effects on our health and environment; however, many are responsible for serious infectious diseases, warranting the need for vaccines against such pathogens. Bioinformatic and experimental technologies are crucial for the development of vaccines. The vaccine design pipeline requires identification of bacteria-specific antigens that can be recognized and can induce a response by the immune system upon infection. Immune system recognition is influenced by the location of a protein. Methods have been developed to determine the subcellular localization (SCL) of proteins in prokaryotes and eukaryotes. Bioinformatic tools such as PSORTb can be employed to determine SCL of proteins, which would be tedious to perform experimentally. Unfortunately, PSORTb often predicts many proteins as having an "Unknown" SCL, reducing the number of antigens to evaluate as potential vaccine targets.

METHOD

We present a new pipeline called subCellular lOcalization prediction for BacteRiAl Proteins (mtx-COBRA). mtx-COBRA uses Meta's protein language model, Evolutionary Scale Modeling, combined with an Extreme Gradient Boosting machine learning model to identify SCL of bacterial proteins based on amino acid sequence. This pipeline is trained on a curated dataset that combines data from UniProt and the publicly available ePSORTdb dataset.

RESULTS

Using benchmarking analyses, nested 5-fold cross-validation, and leave-one-pathogen-out methods, followed by testing on the held-out dataset, we show that our pipeline predicts the SCL of bacterial proteins more accurately than PSORTb.

CONCLUSIONS

mtx-COBRA provides an accessible pipeline that can more efficiently classify bacterial proteins with currently "Unknown" SCLs than existing bioinformatic and experimental methods.

Targeting Wnt signaling for improved glioma immunotherapy

Introduction

Despite aggressive standard-of-care therapy, including surgery, radiation, and chemotherapy, glioblastoma recurrence is almost inevitable and uniformly lethal. Activation of glioma-intrinsic Wnt/β-catenin signaling is associated with a poor prognosis and the proliferation of glioma stem-like cells, leading to malignant transformation and tumor progression. Impressive results in a subset of cancers have been obtained using immunotherapies including anti-CTLA4, anti-PD-1, and anti-PD-L1 or chimeric antigen receptor (CAR) T cell therapies. However, the heterogeneity of tumors, low mutational burden, single antigen targeting, and associated antigen escape contribute to non-responsiveness and potential tumor recurrence despite these therapeutic efforts. In the current study, we determined the effects of the small molecule, highly specific Wnt/CBP (CREB Binding Protein)/β-catenin antagonist ICG-001, on glioma tumor cells and the tumor microenvironment (TME)-including its effect on immune cell infiltration, blood vessel decompression, and metabolic changes.

Methods

Using multiple glioma patient-derived xenografts cell lines and murine tumors (GL261, K-Luc), we demonstrated in vitro cytostatic effects and a switch from proliferation to differentiation after treatment with ICG-001.

Results

In these glioma cell lines, we further demonstrated that ICG-001 downregulated the CBP/β-catenin target gene Survivin/BIRC5-a hallmark of Wnt/CBP/β-catenin inhibition. We found that in a syngeneic mouse model of glioma (K-luc), ICG-001 treatment enhanced tumor infiltration by CD3+ and CD8+ cells with increased expression of the vascular endothelial marker CD31 (PECAM-1). We also observed differential gene expression and induced immune cell infiltration in tumors pretreated with ICG-001 and then treated with CAR T cells as compared with single treatment groups or when ICG-001 treatment was administered after CAR T cell therapy.

Discussion

We conclude that specific Wnt/CBP/β-catenin antagonism results in pleotropic changes in the glioma TME, including glioma stem cell differentiation, modulation of the stroma, and immune cell activation and recruitment, thereby suggesting a possible role for enhancing immunotherapy in glioma patients.

Lifestyle behaviour patterns in the prevention of type 2 diabetes mellitus: the Fukushima Health Database 2015-2020

OBJECTIVES

Lifestyle behaviours associated with the incidence of type 2 diabetes mellitus (T2DM) need further clarification using health insurance data.

STUDY DESIGN

This is a cohort study.

METHODS

In 2015, 193,246 participants aged 40-74 years attended the specific health checkups and were observed up to 2020 in Fukushima, Japan. Using the principal component analysis, we identified two patterns from ten lifestyle behaviour questions, namely, the "diet-smoking" pattern (including smoking, alcohol drinking, skipping breakfast, eating fast, late dinner, and snacking) and the "physical activity-sleep" pattern (including physical exercise, walking equivalent activity, walking fast, and sufficient sleep). Then, individual pattern scores were calculated; the higher the scores, the healthier the behaviours.

RESULTS

The accumulative incidence rate of T2DM was 630.5 in men and 391.9 in women per 100,000 person-years in an average of 4 years of follow-up. Adjusted for the demographic and cardiometabolic factors at the baseline, the hazard ratio (95% confidence interval) of the highest versus lowest quartile scores of the "diet-smoking" pattern for T2DM risk was 0.82 (0.72, 0.92; P for trend = 0.002) in men and 0.87 (0.76, 1·00; P for trend = 0.034) in women; that of the "physical activity-sleep" pattern was 0.92 (0.82, 1·04; P for trend = 0.0996) in men and 0.92 (0.80, 1·06; P for trend = 0.372) in women. The "physical activity-sleep" pattern showed a significant inverse association in non-overweight men.

CONCLUSIONS

Lifestyle behaviour associated with a healthy diet and lack of smoking may significantly lower the risk of T2DM in middle-aged Japanese adults.

Development and validation of a hybrid immunoaffinity LC-MS/MS assay for quantitation of total antibody (TAb) from an antibody drug conjugate (ADC) PYX-201 in human plasma

A hybrid immunoaffinity LC-MS/MS assay was developed and validated for the quantitation of total antibody (TAb) from an antibody drug conjugate (ADC) PYX-201 in human plasma. PYX-201 was proteolyzed using trypsin, and a characteristic peptide fragment PYX-201 P1 with ten amino acids IPPTFGQGTK from the complementarity-determining regions (CDRs) was used as a surrogate for the quantitation of the TAb from PYX-201. Stable isotope labelled (SIL) peptide I(13C6, 15N)PPTFG(13C9, 15N)QGTK was used as the internal standard (IS). We performed chromatographic analysis using a Waters Acquity BEH Phenyl column (2.1 mm × 50 mm, 1.7 µm). Quantification of PYX-201 TAb was carried out on a Sciex triple quadrupole mass spectrometer API 6500 using multiple reaction monitoring (MRM) mode with positive electrospray ionization. To validate PYX-201 TAb, a concentration range of 0.0500 µg/mL to 20.0 µg/mL was used, yielding a correlation coefficient (r) of ≥ 0.9947. For intra-assay measurements, the percent relative error (%RE) ranged from -23.2% to 1.0%, with a coefficient of variation (%CV) of ≤ 14.2%. In terms of inter-assay measurements, the %RE was between -10.5% and -5.7%, with a %CV of ≤ 12.7%. The average recovery of the analyte was determined to be 81.4%, while the average recovery of the internal standard (IS) was 97.2%. Furthermore, PYX-201 TAb demonstrated stability in human plasma and human whole blood under various tested conditions. This assay has been successfully applied to human sample analysis to support a clinical study.

A sensitive and rapid LC-MS/MS assay for quantitation of free payload Aur0101 from antibody drug conjugate (ADC) PYX-201 in human plasma

PYX-201 is an investigational antibody drug conjugate (ADC) with an engineered, fully human IgG1 antibody, a cleavable chemical linker, and a toxin (Aur0101) with an average drug-antibody ratio (DAR) of ∼ 4. A sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and fully validated to determine the presence in human plasma, of free payload Aur0101 from PYX-201 to assess drug safety and efficacy. Aur0101 and its deuterated internal standard (IS), Aur0101_d₈, were extracted from 25 µL of human plasma using a solid liquid extraction (SLE) method. Chromatographic analysis was carried out on a Waters Acquity UPLC BEH C18 (2.1 mm × 50 mm, 1.7 µm, 130 A) column. Quantitation of free Aur0101 was conducted on a Sciex triple quadrupole mass spectrometer API 6500 + using multiple reaction monitoring (MRM) mode via positive electrospray ionization. The calibration curve was linear over the concentration range of 25.0 to 12,500 pg/mL with correlation coefficient, r² ≥ 0.9988. The intra-assay %RE was between -4.3% to 14.3% with % CV was ≤ 6.2%. The inter-assay %RE was between -0.2% to 9.5% with % CV was ≤ 6.1%. The average analyte recovery was 89.7% and the average IS recovery was 88.7%. Aur0101 was found to be stable in human plasma and human whole blood under various tested conditions with and without the presence of PYX-201. To our knowledge, this is the first published fully validated assay for free, unconjugated Aur0101 in any matrix, from any species. This assay has been successfully applied to clinical sample analysis to support clinical studies.

Pulmonary Metastases From Primary Thigh Leiomyosarcoma: A Case Report and Review of the Literature

Leiomyosarcoma is a rare type of tumor of smooth muscle cells that can occur anywhere in the body. However, it typically occurs in the retroperitoneum, intra-abdominal sites, and uterus in people over 65. Here is a case of a 71-year-old male with a history of melanoma of the skin who presented with a rapidly enlarging, non-tender lump at his left lateral thigh area that was later diagnosed as pleomorphic dedifferentiated leiomyosarcoma. The patient underwent radical resection of the tumor and the attached vastus lateralis muscle and partial lateral collateral ligament, followed by radiation therapy to the resected site. He had no evidence of tumor recurrence on follow-up imaging for several months until he was found to have metastatic disease to the lungs on a surveillance CT one year later. A biopsy confirmed that the lung nodules were leiomyosarcoma metastases, and the patient was started on chemotherapy and stereotactic body radiation therapy (SBRT). Upon reviewing the literature, a few cases of leiomyosarcoma arising from the thigh muscles were found.

Bioanalysis of an antibody drug conjugate (ADC) PYX-201 in human plasma using a hybrid immunoaffinity LC-MS/MS approach

PYX-201 is an anti-extra domain B splice variant of fibronectin (EDB + FN) antibody drug conjugate (ADC) composed of a fully human IgG1 antibody, a cleavable mcValCitPABC linker, and four Auristatin 0101 (Aur0101, PF-06380101) payload molecules. To better understand the pharmacokinetic (PK) profile of PYX-201 after it is administered to cancer patients, the development of a reliable bioanalytical assay to accurately and precisely quantitate PYX-201 in human plasma is required. In this manuscript, we present a hybrid immunoaffinity LC-MS/MS assay used to successfully analyze PYX-201 in human plasma. PYX-201 was enriched by MABSelect beads coated with protein A in human plasma samples. The bound proteins were subjected to "on-bead" proteolysis with papain to release the payload Aur0101. The stable isotope labelled internal standard (SIL-IS) Aur0101-d₈ was added and the released Aur0101 was quantified as a surrogate for the total ADC concentration. The separation was performed on a UPLC C18 column coupled with tandem mass spectrometry. The LC-MS/MS assay was validated over the range 0.0250 to 25.0 µg/mL with excellent accuracy and precision. The overall accuracy (%RE) was between -3.8% and -0.1% and the inter-assay precision (%CV) was <5.8%. PYX-201 was found to be stable in human plasma for at least 24 h on ice, 15 days after being stored at -80 °C, as well as after five freeze/thaw cycles of being frozen at -25 °C or -80 °C and thawed on ice. The assay this paper reports on, has been successfully applied to human sample analysis to support clinical studies.

Internal Jugular Venous Thrombosis With Superior Vena Cava Syndrome: A Rare First Presentation of Gray Zone Lymphoma

Gray zone lymphoma (GZL) is defined as a B-cell lymphoma with intermediate features between both diffuse large B-cell lymphoma (DLBCL) and classical Hodgkin lymphoma (CHL). GZL is an aggressive disease, which in addition to the B-symptoms, can present as shortness of breath and neck swelling from underlying superior vena cava (SVC) syndrome. Thrombosis of the internal jugular vein (IJVT) is rare and usually associated with head and neck infection, intravenous (IV) drug abuse, and central venous catheter placement. GZL's initial presentation as IJVT with SVC syndrome is very uncommon. We report the case of a 47-year-old female presenting with neck swelling and shortness of breath. Initial investigations were oriented at the thyroid gland. A computerized tomography (CT) scan of the chest, neck, and head showed a large anterior/superior mediastinal soft tissue mass with left IJVT. An excisional biopsy of the left axillary lymph node confirmed the diagnosis of GZL. The mediastinal lymphoma can compress the internal jugular vein and also release thrombogenic substances that can cause IJVT. The compression of the SVC by the lymphoma and the IJVT formation can cause SVC syndrome. Both of these conditions can be life-threatening and should be identified in the early stages to prevent complications.

Prevalence trends of metabolic syndrome in residents of postdisaster Fukushima: a longitudinal analysis of Fukushima Health Database 2012-2019

OBJECTIVES

The study aimed to evaluate the long-term metabolic risk profiles of Fukushima residents after the Great East Japan Earthquake of March 2011.

STUDY DESIGN

This was a cross-sectional and a longitudinal design.

METHODS

The Fukushima Health Database (FDB) contains 2,331,319 annual health checkup records of participants aged 40-74 years between 2012 and 2019. We checked the validity of the FDB by comparing the prevalence of metabolic factors with the National Database of Health Insurance Claims and Specific Health Checkups (NDB). We applied a regression analysis to determine the changes and project the trends of metabolic factors over the years.

RESULTS

Compared to the NDB, the prevalence of metabolic factors in Fukushima was higher than the country average from 2013 to 2018, and they showed the same trends as those from the FDB. The prevalence of metabolic syndrome (MetS) increased from 18.9% in 2012 to 21.4% in 2019 (an annual increase of 2.74%) in men and from 6.8 to 7.4% (an annual increase of 1.80%) in women in Fukushima. The standardized prevalence of MetS, being overweight, and diabetes is projected to continue increasing, with disparities among subareas being higher in evacuees than in non-evacuees. An annual decrease of 0.38-1.97% in hypertension was mainly observed in women.

CONCLUSIONS

The prevalence of metabolic risk is higher in Fukushima as compared to the country average. The increasing metabolic risk in subareas, including the evacuation zone, highlights the need to control MetS in Fukushima residents.

CD47 antisense oligonucleotide treatment attenuates obesity and its-associated metabolic dysfunction

Previous study from our lab has revealed a new role of CD47 in regulating adipose tissue function, energy homeostasis and the development of obesity and metabolic disease in CD47 deficient mice. In this study, the therapeutic potential of an antisense oligonucleotide (ASO) targeting to CD47 in obesity and its-associated complications was determined in two obese mouse models (diet induced and genetic models). In diet induced obesity, male C57BL6 mice were fed with high fat (HF) diet to induce obesity and then treated with CD47ASO or control ASO for 8 weeks. In genetic obese mouse model, male six-week old ob/ob mice were treated with ASOs for 9 weeks. We found that CD47ASO treatment reduced HF diet-induced weight gain, decreased fat mass, prevented dyslipidemia, and improved glucose tolerance. These changes were accompanied by reduced inflammation in white adipose tissue and decreased hepatic steatosis. This protection was also seen in CD47ASO treated ob/ob mice. Mechanistically, CD47ASO treatment increased mice physical activity and energy expenditure, contributing to weight loss and improved metabolic outcomes in obese mice. Collectively, these findings suggest that CD47ASO might serve as a new treatment option for obesity and its-associated metabolic complications.

Multiplex Hybrid Antigen-Capture LC-MRM Quantification in Sera and Nasal Lining Fluid of AZD7442, a SARS-CoV-2-Targeting Antibody Combination

AZD7442 (tixagevimab [AZD8895]/cilgavimab [AZD1061]) is a monoclonal antibody (mAb) combination in development for the prevention and treatment of coronavirus disease 2019. Traditionally, bioanalysis of mAbs is performed using ligand binding assays (LBAs), which offer sensitivity, robustness, and ease of implementation. However, LBAs frequently require generation of critical reagents that typically take several months. Instead, we developed a highly sensitive (5 ng/mL limit of quantification) method using a hybrid LBA-liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) approach for quantification of the two codosed antibodies in serum and nasal lining fluid (NLF), a rare matrix. The method was optimized by careful selection of multiple reaction monitoring, capture reagents, magnetic beads, chromatographic conditions, evaluations of selectivity, and matrix effect. The final assay used viral spike protein receptor-binding domain as capture reagent and signature proteotypic peptides from the complementarity-determining region of each mAb for detection. In contrast to other methods of similar/superior sensitivity, our approach did not require multidimensional separations and can be operated in an analytical flow regime, ensuring high throughput and robustness required for clinical analysis at scale. The sensitivity of this method significantly exceeds typical sensitivity of ∼100 ng/mL for analytical flow 1D LBA-LC-MS/MS methods for large macromolecules, such as antibodies. Furthermore, infection and vaccination status did not impact method performance, ensuring method robustness and applicability to a broad patient population. This report demonstrated the general applicability of the hybrid LBA-LC-MS/MS approach to platform quantification of antibodies with high sensitivity and reproducibility, with specialized extension to matrices of increasing interest, such as NLF.

Pneumatosis coli in preterm neonates: Can they be managed more conservatively to maintain the intestinal milieu?

Necrotising enterocolitis (NEC) is a severe gastrointestinal disease mostly in premature infants due to intestinal necrosis. The aetiology of NEC is multifactorial and includes gut immaturity, intestinal dysbiosis and exaggerated intestinal mucosal reactivity to microbial ligands. Radiographic evidence of pneumatosis intestinalis has been a critical feature for diagnosing NEC Bell stage ≥IIA and recommended treatment includes prolonged antibiotics (7-14 days) while off enteral feeds. Pneumatosis coli (Pcoli), a mild or benign form of NEC, is characterised by pneumatosis limited to the colon in an infant having haematochezia, negative septic screening and no systemic signs. We report two healthy preterm infants with haematochezia and colonic pneumatosis while on breast milk feeds. The sepsis screen was negative. A brief period of antibiotics and gut rest led to the spontaneous resolution of haematochezia and colonic pneumatosis, facilitating early enteral feeds. This case report emphasises the need to differentiate NEC from benign Pcoli.

Anti-CD47 antibody treatment attenuates liver inflammation and fibrosis in experimental non-alcoholic steatohepatitis models

BACKGROUND & AIMS

With the epidemic burden of obesity and metabolic diseases, nonalcoholic fatty liver disease (NAFLD) including steatohepatitis (NASH) has become the most common chronic liver disease in the western world. NASH may progress to cirrhosis and hepatocellular carcinoma. Currently, no treatment is available for NASH. Therefore, finding a therapy for NAFLD/NASH is in urgent need. Previously we have demonstrated that mice lacking CD47 or its ligand thrombospondin1 (TSP1) are protected from obesity-associated NALFD. This suggests that CD47 blockade might be a novel treatment for obesity-associated metabolic disease. Thus, in this study, the therapeutic potential of an anti-CD47 antibody in NAFLD progression was determined.

METHODS

Both diet-induced NASH mouse model and human NASH organoid model were utilized in this study. NASH was induced in mice by feeding with diet enriched with fat, fructose and cholesterol (AMLN diet) for 20 weeks and then treated with anti-CD47 antibody or control IgG for 4 weeks. Body weight, body composition and liver phenotype were analysed.

RESULTS

We found that anti-CD47 antibody treatment did not affect mice body weight, fat mass or liver steatosis. However, liver immune cell infiltration, inflammation and fibrosis were significantly reduced by anti-CD47 antibody treatment. In vitro data further showed that CD47 blockade prevented hepatic stellate cell activation and NASH progression in a human NASH organoid model.

CONCLUSION

Collectively, these data suggest that anti-CD47 antibody might be a new therapeutic option for obesity-associated NASH and liver fibrosis.

Dose-dependent thresholds of dexamethasone destabilize CAR T-cell treatment efficacy

Chimeric antigen receptor (CAR) T-cell therapy is potentially an effective targeted immunotherapy for glioblastoma, yet there is presently little known about the efficacy of CAR T-cell treatment when combined with the widely used anti-inflammatory and immunosuppressant glucocorticoid, dexamethasone. Here we present a mathematical model-based analysis of three patient-derived glioblastoma cell lines treated in vitro with CAR T-cells and dexamethasone. Advanced in vitro experimental cell killing assay technologies allow for highly resolved temporal dynamics of tumor cells treated with CAR T-cells and dexamethasone, making this a valuable model system for studying the rich dynamics of nonlinear biological processes with translational applications. We model the system as a nonautonomous, two-species predator-prey interaction of tumor cells and CAR T-cells, with explicit time-dependence in the clearance rate of dexamethasone. Using time as a bifurcation parameter, we show that (1) dexamethasone destabilizes coexistence equilibria between CAR T-cells and tumor cells in a dose-dependent manner and (2) as dexamethasone is cleared from the system, a stable coexistence equilibrium returns in the form of a Hopf bifurcation. With the model fit to experimental data, we demonstrate that high concentrations of dexamethasone antagonizes CAR T-cell efficacy by exhausting, or reducing the activity of CAR T-cells, and by promoting tumor cell growth. Finally, we identify a critical threshold in the ratio of CAR T-cell death to CAR T-cell proliferation rates that predicts eventual treatment success or failure that may be used to guide the dose and timing of CAR T-cell therapy in the presence of dexamethasone in patients.

Bioengineering and gene-editing technologies have paved the way for advance immunotherapies that can target patient-specific tumor cells. One of these therapies, chimeric antigen receptor (CAR) T-cell therapy has recently shown promise in treating glioblastoma, an aggressive brain cancer often with poor patient prognosis. Dexamethasone is a commonly prescribed anti-inflammatory medication due to the health complications of tumor associated swelling in the brain. However, the immunosuppressant effects of dexamethasone on the immunotherapeutic CAR T-cells are not well understood. To address this issue, we use mathematical modeling to study in vitro dynamics of dexamethasone and CAR T-cells in three patient-derived glioblastoma cell lines. We find that in each cell line studied there is a threshold of tolerable dexamethasone concentration. Below this threshold, CAR T-cells are successful at eliminating the cancer cells, while above this threshold, dexamethasone critically inhibits CAR T-cell efficacy. Our modeling suggests that in the presence of high dexamethasone reduced CAR T-cell efficacy, or increased exhaustion, can occur and result in CAR T-cell treatment failure.

A review of child sexual abuse cases presenting to a paediatric emergency department

INTRODUCTION

Child sexual abuse (CSA) adversely affects a child's growth and well-being. This study aimed to describe the profile of children presenting to a tertiary paediatric emergency department(ED) with CSA.

METHODS

Children 0-16 years old presenting to KK Women's and Children's Hospital ED from June 2016 to August 2020 with sexual abuse were retrospectively reviewed. We performed a secondary analysis on girls and stratified them by age <13 and ≥13 years old.

RESULTS

There were 790 patients who made 833 visits for CSA. Victims were predominantly girls (747, 94.8%) and perpetrators were predominantly men (763, 96.6%). The abuse first occurred before the age of 13 years in 315 victims (39.9%). For 468 (59.2%), more than one incident occurred before presentation. Compared to girls ≥13 years old, girls <13 years old were more frequently abused by a family member (47.7% versus 8.0%, P<0.001) and abused in their own home (55.7% vs 21.0%, P<0.001). Among all children, parental divorce and the absence of one or both biological parents in the household were prevalent, with 287/783 (36.7%) having divorced parents, and only 374/784 (47.8%) residing with both biological parents.

CONCLUSION

The findings highlight common characteristics of CSA cases, and can aid the future identification and protection of vulnerable children. The fact that most children presented after more than one incident suggests the need to more closely monitor and protect potentially at-risk children.

Development of a cost-effective automated platform to produce human liver spheroids for basic and applied research

Liver disease represents an increasing cause of global morbidity and mortality. Currently, liver transplant is the only treatment curative for end-stage liver disease. Donor organs cannot meet the demand and therefore scalable treatments and new disease models are required to improve clinical intervention. Pluripotent stem cells represent a renewable source of human tissue. Recent advances in three-dimensional cell culture have provided the field with more complex systems that better mimic liver physiology and function. Despite these improvements, current cell-based models are variable in performance and expensive to manufacture at scale. This is due, in part, to the use of poorly defined or cross-species materials within the process, severely affecting technology translation. To address this issue, we have developed an automated and economical platform to produce liver tissue at scale for modelling disease and small molecule screening. Stem cell derived liver spheres were formed by combining hepatic progenitors with endothelial cells and stellate cells, in the ratios found within the liver. The resulting tissue permitted the study of human liver biology 'in the dish' and could be scaled for screening. In summary, we have developed an automated differentiation system that permits reliable self-assembly of human liver tissue for biomedical application. Going forward we believe that this technology will not only serve as anin vitroresource, and may have an important role to play in supporting failing liver function in humans.

Data of pre-and post-operative images and video of marsupialization of congenital vallecular cyst by coblation technique

This data describes the modern surgical treatment of congenital vallecular cyst in a term newborn infant who developed neonatal stridor on day 1 of life. Diagnosis was made by nasoendoscopy and the infant underwent successful treatment by marsupialization via coblation technique. Images and videos were taken during the procedure both pre and post-operatively. This case highlights the need for an interdisciplinary evaluation of persistent neonatal stridor in newborn infants for early diagnosis and intervention to avoid critical airway obstruction and potentially fatal outcomes, DOI: 10.1016/j.epsc.2020.101460[1].

Peax: Interactive Visual Pattern Search in Sequential Data Using Unsupervised Deep Representation Learning

We present Peax, a novel feature-based technique for interactive visual pattern search in sequential data, like time series or data mapped to a genome sequence. Visually searching for patterns by similarity is often challenging because of the large search space, the visual complexity of patterns, and the user's perception of similarity. For example, in genomics, researchers try to link patterns in multivariate sequential data to cellular or pathogenic processes, but a lack of ground truth and high variance makes automatic pattern detection unreliable. We have developed a convolutional autoencoder for unsupervised representation learning of regions in sequential data that can capture more visual details of complex patterns compared to existing similarity measures. Using this learned representation as features of the sequential data, our accompanying visual query system enables interactive feedback-driven adjustments of the pattern search to adapt to the users' perceived similarity. Using an active learning sampling strategy, Peax collects user-generated binary relevance feedback. This feedback is used to train a model for binary classification, to ultimately find other regions that exhibit patterns similar to the search target. We demonstrate Peax's features through a case study in genomics and report on a user study with eight domain experts to assess the usability and usefulness of Peax. Moreover, we evaluate the effectiveness of the learned feature representation for visual similarity search in two additional user studies. We find that our models retrieve significantly more similar patterns than other commonly used techniques.

Abstract P5-09-12: Germline mutation in TP53 gene in a cohort of 2,561 Chinese high-risk breast cancer patients using multigene panel testing

Background: Li-Fraumeni syndrome (LFS) is a rare autosomal genetic disorder with germline TP53 mutations. Patients with TP53 mutations have a higher risk of developing breast cancer than those harboring BRCA mutations. Although limited studies have shown that TP53 mutation carriers are less responsive to low dose radiation and more susceptible to induce new malignancies from radiotherapy. Moreover screening strategies allows early detection of a spectrum of cancers related to TP53 mutations. From work of BRCA mutations where over 40% novel mutations were detected in Chinese cohort, it is important to evaluate the frequency of TP53 mutation in Chinese to better understand the spectrum to guide appropriate clinical management of these high risk individuals.

Methods: TP53 gene mutation screening was performed on 2,561 high-risk breast cancer patients using multigene panel testing. The patients were accrued by Hong Kong Hereditary and High Risk Breast Cancer Program from March 2007 to May 2018. All detected pathogenic mutations were further validated by bi-directional DNA sequencing and analyzed by our in-house developed bioinformatics pipeline.

Results: Sixteen distinct pathogenic or likely pathogenic variants were identified, and 3 of them were de novo TP53 mutations (18.75%). The mean age of patients who harbored TP53 mutation was 30.44 years (range 18-44), and 50% of the tumors were bilateral breast cancer. Of sixteen different pathogenic mutations, majority of them were missense mutation (87.5%), and 2 were nonsense mutation (12.5%). Four of the sixteen TP53 mutation carriers had family history of breast cancer, while others had a family history of lung cancer (43.75%).

Conclusion: This study revealed that seven patients were found to habor TP53 mutation even when they did not meet the criteria of LFS of LFS-like phenotype, implicated the importance of using multigene panel test for probands and their relatives to offer a comprehensive surveillance programe for TP53 carriers.

Citation Format: Kwong A, Shin V, Au CH, Ho C, Slavin T, Weitzel J, Chan TL, Ma E. Germline mutation in TP53 gene in a cohort of 2,561 Chinese high-risk breast cancer patients using multigene panel testing [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-09-12.

Structural Parameter of Orientational Order to Predict the Boson Vibrational Anomaly in Glasses

It has so far remained a major challenge to quantitatively predict the boson peak, a THz vibrational anomaly universal for glasses, from features in the amorphous structure. Using molecular dynamics simulations of a model Cu_{50}Zr_{50} glass, we decompose the boson peak to contributions from atoms residing in different types of Voronoi polyhedra. We then introduce a microscopic structural parameter to depict the "orientational order," using the vector pointing from the center atom to the farthest vertex of its Voronoi coordination polyhedron. This order parameter represents the most probable direction of transverse vibration at low frequencies. Its magnitude scales linearly with the boson peak intensity, and its spatial distribution accounts for the quasilocalized modes. This correlation is shown to be universal for different types of glasses.

Universal intracellular biomolecule delivery with precise dosage control

Intracellular delivery of mRNA, DNA, and other large macromolecules into cells plays an essential role in an array of biological research and clinical therapies. However, current methods yield a wide variation in the amount of material delivered, as well as limitations on the cell types and cargoes possible. Here, we demonstrate quantitatively controlled delivery into a range of primary cells and cell lines with a tight dosage distribution using a nanostraw-electroporation system (NES). In NES, cells are cultured onto track-etched membranes with protruding nanostraws that connect to the fluidic environment beneath the membrane. The tight cell-nanostraw interface focuses applied electric fields to the cell membrane, enabling low-voltage and nondamaging local poration of the cell membrane. Concurrently, the field electrophoretically injects biomolecular cargoes through the nanostraws and into the cell at the same location. We show that the amount of material delivered is precisely controlled by the applied voltage, delivery duration, and reagent concentration. NES is highly effective even for primary cell types or different cell densities, is largely cargo agnostic, and can simultaneously deliver specific ratios of different molecules. Using a simple cell culture well format, the NES delivers into >100,000 cells within 20 s with >95% cell viability, enabling facile, dosage-controlled intracellular delivery for a wide variety of biological applications.

A Comparative Analysis of the Usefulness of Survival Prediction Models for Patients with Glioblastoma in the Temozolomide Era: The Importance of Methylguanine Methyltransferase Promoter Methylation, Extent of Resection, and Subventricular Zone Location

OBJECTIVE

Several survival prediction models for patients with glioblastoma have been proposed, but none is widely used. This study aims to identify the predictors of overall survival (OS) and to conduct an independent comparative analysis of 5 prediction models.

METHODS

Multi-institutional data from 159 patients with newly diagnosed glioblastoma who received adjuvant temozolomide concomitant chemoradiotherapy (CCRT) were collected. OS was assessed by Cox proportional hazards regression and adjusted for known prognostic factors. An independent CCRT patient cohort was used to externally validate the 1) RTOG (Radiation Therapy Oncology Group) recursive partitioning analysis (RPA) model, 2) Yang RPA model, and 3) Wee RPA model, Chaichana model, and the RTOG nomogram model. The predictive accuracy for each model at 12-month survival was determined by concordance indices. Calibration plots were performed to ascertain model prediction precision.

RESULTS

The median OS for patients who received CCRT was 19.0 months compared with 12.7 months for those who did not (P < 0.001). Independent predictors were: 1) subventricular zone II tumors (hazard ratio [HR], 1.6; 95% confidence interval [CI], 1.0-2.5); 2) methylguanine methyltransferase promoter methylation (HR, 0.36; 95% CI, 0.2-0.6); and 3) extent of resection of >85% (HR, 0.59; 95% CI, 0.4-0.9). For 12-month OS prediction, the RTOG nomogram model was superior to the RPA models with a c-index of 0.70. Calibration plots for 12-month survival showed that none of the models was precise, but the RTOG nomogram performed relatively better.

CONCLUSIONS

The RTOG nomogram best predicted 12-month OS. Methylguanine methyltransferase promoter methylation status, subventricular zone tumor location, and volumetric extent of resection should be considered when constructing prediction models.

Melt fluxing to elevate the forming ability of Al-based bulk metallic glasses

Salt-fluxing treatment is an effective technique to improve the glass-forming ability (GFA) of bulk metallic glass (BMG)-forming melts, as demonstrated before in Pd- and Fe-based systems. However, it has been challenging to develop similar fluxing protocol for more reactive melts, such as Al-rich BMG-forming systems. Here we design new fluxing agents, from a thermodynamics perspective that takes into account combined effects of physical absorption and chemical absorption (reaction) between the fluxing agents and oxide inclusions. MgCl₂-CaCl₂ composite salts were selected, and their fluxing effects were systematically studied on an Al₈₆Ni_6.75Co_2.25Y_3.25La_1.75 alloy, the best BMG-forming composition reported thus far for Al-rich alloy systems. The oxygen content was found to continuously decrease in the master alloy with increasing cycles of salt-fluxing treatment, with chlorate products on the surface suggesting concurrent physical absorption and chemical reaction. The fluxing treatment developed has enabled a record critical size (diameter) of 2.5 mm for Al-based BMGs. Our finding is thus an advance in developing highly desirable Al-based BMGs, and also provides guidance for designing processing protocol to produce larger-sized BMGs in other reactive systems.

Servo controlled versus manual cooling methods in neonates with hypoxic ischemic encephalopathy

BACKGROUND

Therapeutic hypothermia is known to improve outcomes in neonates with hypoxic ischemic encephalopathy (HIE). There are no studies that have compared servo controlled cooling (SCC) versus manually controlled cooling (MCC) methods in HIE.

AIM

To compare the outcomes of SCC versus MCC in neonates with HIE.

METHODS AND OUTCOME MEASURES

Between Jan 2008 and May 2011, MCC with cool-gel packs was used to achieve rectal temperatures of 33.5 to 34.5°C in our units. Subsequently, we changed to SCC to achieve rectal temperatures of 33 to 34°C. 105 neonates received SCC whereas 95 received MCC. Retrospective study with multivariate analysis was conducted comparing thermoregulation (primary outcome) and neurodevelopmental outcomes of SCC versus MCC.

RESULTS

In the SCC group, 72.3% had stage 2 or 3 HIE versus 77.9% in the MCC. The remaining had stage 1, but attending neonatologists decided to provide cooling. Prescribed rectal temperatures were achieved in 80.5% (5768/7168) instances in SCC versus 72.9% (4449/6108) in MCC (p<0.0001). There were no significant differences in the incidence of 'death or moderate-severe disability' [SCC 26/85 vs MCC 26/87, adjusted odds ratio: 1.29, 95% CI: 0.48, 3.42; p=0.614]. The results were similar after excluding stage 1 HIE [SCC 25/66 vs MCC 26/69, adjusted odds ratio: 1.01, 95% CI: 0.50, 2.02; p=0.981].

CONCLUSIONS

SCC resulted in better thermoregulation in neonates undergoing therapeutic hypothermia. There were no significant differences in neurodevelopmental outcomes, but the study was underpowered to answer this. Randomized trials are needed to fine-tune various aspects of TH in neonates with HIE.

Genetic characterization of a rare H12N3 avian influenza virus isolated from a green-winged teal in Japan

This study reports on the genetic characterization of an avian influenza virus, subtype H12N3, isolated from an Eurasian green-winged teal (Anas crecca) in Japan in 2009. The entire genome sequence of the isolate was analyzed, and phylogenetic analyses were conducted to characterize the evolutionary history of the isolate. Phylogenetic analysis of the hemagglutinin and neuraminidase genes indicated that the virus belonged to the Eurasian-like avian lineage. Molecular dating indicated that this H12 virus is likely a multiple reassortant influenza A virus. This is the first reported characterization of influenza A virus subtype H12N3 isolated in Japan and these data contribute to the accumulation of knowledge on the genetic diversity and generation of novel influenza A viruses.

Exploring structural motifs necessary for substrate binding in the active site of Escherichia coli pantothenate kinase

The coenzyme A (CoA) biosynthetic enzymes have been used to produce various CoA analogues, including mechanistic probes of CoA-dependent enzymes such as those involved in fatty acid biosynthesis. These enzymes are also important for the activation of the pantothenamide class of antibacterial agents, and of a recently reported family of antibiotic resistance inhibitors. Herein we report a study on the selectivity of pantothenate kinase, the first and rate limiting step of CoA biosynthesis. A robust synthetic route was developed to allow rapid access to a small library of pantothenate analogs diversified at the β-alanine moiety, the carboxylate or the geminal dimethyl group. All derivatives were tested as substrates of Escherichia coli pantothenate kinase (EcPanK). Four derivatives, all N-aromatic pantothenamides, proved to be equivalent to the benchmark N-pentylpantothenamide (N5-pan) as substrates of EcPanK, while two others, also with N-aromatic groups, were some of the best substrates reported for this enzyme. This collection of data provides insight for the future design of PanK substrates in the production of useful CoA analogues.

Nanostructured high-strength molybdenum alloys with unprecedented tensile ductility

The high-temperature stability and mechanical properties of refractory molybdenum alloys are highly desirable for a wide range of critical applications. However, a long-standing problem for these alloys is that they suffer from low ductility and limited formability. Here we report a nanostructuring strategy that achieves Mo alloys with yield strength over 800 MPa and tensile elongation as large as ~ 40% at room temperature. The processing route involves a molecular-level liquid-liquid mixing/doping technique that leads to an optimal microstructure of submicrometre grains with nanometric oxide particles uniformly distributed in the grain interior. Our approach can be readily adapted to large-scale industrial production of ductile Mo alloys that can be extensively processed and shaped at low temperatures. The architecture engineered into such multicomponent alloys offers a general pathway for manufacturing dispersion-strengthened materials with both high strength and ductility.

Microstructural fingerprints of phase transitions in shock-loaded iron

The complex structural transformation in crystals under static pressure or shock loading has been a subject of long-standing interest to materials scientists and physicists. The polymorphic transformation is of particular importance for iron (Fe), due to its technological and sociological significance in the development of human civilization, as well as its prominent presence in the earth's core. The martensitic transformation α→ε (bcc→hcp) in iron under shock-loading, due to its reversible and transient nature, requires non-trivial detective work to uncover its occurrence. Here we reveal refined microstructural fingerprints, needle-like colonies and three sets of {112}<111> twins with a threefold symmetry, with tell-tale features that are indicative of two sequential martensitic transformations in the reversible α→ε phase transition, even though no ε is retained in the post-shock samples. The signature orientation relationships are consistent with previously-proposed transformation mechanisms, and the unique microstructural fingerprints enable a quantitative assessment of the volume fraction transformed.

Pressure tunes electrical resistivity by four orders of magnitude in amorphous Ge2Sb2Te5 phase-change memory alloy

Ge-Sb-Te-based phase-change memory is one of the most promising candidates to succeed the current flash memories. The application of phase-change materials for data storage and memory devices takes advantage of the fast phase transition (on the order of nanoseconds) and the large property contrasts (e.g., several orders of magnitude difference in electrical resistivity) between the amorphous and the crystalline states. Despite the importance of Ge-Sb-Te alloys and the intense research they have received, the possible phases in the temperature-pressure diagram, as well as the corresponding structure-property correlations, remain to be systematically explored. In this study, by subjecting the amorphous Ge(2)Sb(2)Te(5) (a-GST) to hydrostatic-like pressure (P), the thermodynamic variable alternative to temperature, we are able to tune its electrical resistivity by several orders of magnitude, similar to the resistivity contrast corresponding to the usually investigated amorphous-to-crystalline (a-GST to rock-salt GST) transition used in current phase-change memories. In particular, the electrical resistivity drops precipitously in the P = 0 to 8 GPa regime. A prominent structural signature representing the underlying evolution in atomic arrangements and bonding in this pressure regime, as revealed by the ab initio molecular dynamics simulations, is the reduction of low-electron-density regions, which contributes to the narrowing of band gap and delocalization of trapped electrons. At P > 8 GPa, we have observed major changes of the average local structures (bond angle and coordination numbers), gradually transforming the a-GST into a high-density, metallic-like state. This high-pressure glass is characterized by local motifs that bear similarities to the body-centered-cubic GST (bcc-GST) it eventually crystallizes into at 28 GPa, and hence represents a bcc-type polyamorph of a-GST.

The design of long-term effective uranium bioremediation strategy using a community metabolic model

Acetate amendment at uranium contaminated sites in Rifle, CO. leads to an initial bloom of Geobacter accompanied by the removal of U(VI) from the groundwater, followed by an increase of sulfate-reducing bacteria (SRBs) which are poor reducers of U(VI). One of the challenges associated with bioremediation is the decay in Geobacter abundance, which has been attributed to the depletion of bio-accessible Fe(III), motivating the investigation of simultaneous amendments of acetate and Fe(III) as an alternative bioremediation strategy. In order to understand the community metabolism of Geobacter and SRBs during artificial substrate amendment, we have created a genome-scale dynamic community model of Geobacter and SRBs using the previously described Dynamic Multi-species Metabolic Modeling framework. Optimization techniques are used to determine the optimal acetate and Fe(III) addition profile. Field-scale simulation of acetate addition accurately predicted the in situ data. The simulations suggest that batch amendment of Fe(III) along with continuous acetate addition is insufficient to promote long-term bioremediation, while continuous amendment of Fe(III) along with continuous acetate addition is sufficient to promote long-term bioremediation. By computationally minimizing the acetate and Fe(III) addition rates as well as the difference between the predicted and target uranium concentration, we showed that it is possible to maintain the uranium concentration below the environmental safety standard while minimizing the cost of chemical additions. These simulations show that simultaneous addition of acetate and Fe(III) has the potential to be an effective uranium bioremediation strategy. They also show that computational modeling of microbial community is an important tool to design effective strategies for practical applications in environmental biotechnology.

Interfacial Reactions of Mo with Al: Ion mixing Versus Thermal Annealing

Interfacial reactions induced by ion beam mixing and furnace annealing in Al/Mo bilayers are investigated. The amount of interfacial ion m'xing, 4Dt, follows a linear dose dependence for irradiation temperatures ≤80 C. Below room temperature, the mixing efficiency, defined as d(4Dt)/dø, is temperature independent, and agrees fairly well with the prediction of the phenomenological model based on chemically biased diffusion in thermal spike. We conclude that thermal spike mixing dominates for Xe irradiation of Al/Mo at low temperatures. The mixing efficiency becomes temperature-dependent above room temperature with an apparent activation enthalpy of about 0.17±0.02eV. A layer of 15–20 at.% Mo forms by ion mixing, while oAl12 Mo forms upon thermal annealing in a nonuniform fashion starting at 500°C. Reaction of Mo with large-grained Al substrates shows the same nonuniform characteristics as in evaporated Al/Mo bilayers, implying a minor role of grain boundary effects. Oxygen gettered in the Mo film could be an important factor that influences the interfacial reaction.

New structural picture of the Ge2Sb2Te5 phase-change alloy

Using electron microscopy and diffraction techniques, as well as first-principles calculations, we demonstrate that as much as 35% of the total Ge atoms in the cubic phase of Ge2Sb2Te5 locate in tetrahedral environments. The Ge-vacancy interactions play a crucial stabilizing role, leading to Ge-vacancy pairs and the sharing of vacancies that clusters tetrahedral Ge into domains. The Ge2Sb2Te5 structure with coexisting octahedral and tetrahedral Ge produces optical and structural properties in good agreement with experimental data and explains the property contrast as well as the rapid transformation in this phase-change alloy.

Role of miR-143 Regulating DNA Methyltransferases 3A in Breast Cancer

Background and Aims: MicroRNAs (miRNAs) are 19-25-nucleotides regulatory non-protein-coding RNA molecules that regulate the expressions of a wide variety of genes including some involved in cancer development. In particular, decreased expression of miR-143 has been reported in various human cancers including colorectal cancer and B-cell lymphomas. The aim of this study was to elucidate the role of miR-143 dysregulation in breast cancer.Methods: Expression levels of human mature microRNAs (miRNAs) were compared with paired breast carcinomas and adjacent normal tissues by TaqMan real-time PCR based expression arrays. Decreased expression of miR-143 was further confirmed in breast cancer cell lines and paired breast tumors and normal adjacent tissues by qRT-PCR. Potential targets of miR-143 were defined. The functional effect of miR-143 and its targets was performed in human breast cancer cell lines to confirm target association.Results: Down-regulation of miR-143 was verified in both human breast cancer cell lines and 80% (12/15) of breast tumors (P &lt; 0.001). DNA methyltranferase 3A (DNMT3A), one of a key enzyme involved in DNA methylation, was defined as a potential target of miR-143 by in-silico analysis. Overexpression of miR-143 in breast cancer cell lines down-regulated expression of DNMT3A, decreased tumor cell growth by MTT assay and soft agar colony formation assay. DNMT3A was demonstrated to be a direct target of miR-143 by luciferase reporter assay. Inverse correlation between DNMT3A protein and miR-143 was found in tumor and normal breast tissues.Conclusions: In this study, we show for the first time in breast cancer that miR-143 specifically targeted DNMT3A and the expression of miR-143 was inversely correlated with DNMT3A expression. Our findings demonstrated that down-regulation of miR-143 and up-regulation of DNMT3A are significant changes in breast tumors. These findings indicate a tumor suppressive role of miR-143 in epigenetic aberration of breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3148.

Nature of atomic bonding and atomic structure in the phase-change Ge2Sb2Te5 glass

Using electronic structure calculations, we demonstrate a global valence alternation in the amorphous Ge2Sb2Te5, a prototype phase-change alloy for data storage. The resulting p bonding profoundly influences the local atomic structure, leading to right-angle components similar to those in the crystalline counterpart of this chalcogenide glass. The dominance of p bonding is revealed by (i) distributions of the coordination number (CN) and the bond angle, for truly bonded atoms determined based on the electron localization function, and (ii) a direct evaluation of the p (and s) orbital occupation probability for the CN=3 Ge atoms that form 90 degree bonds with neighbors.

Atomic shuffling dominated mechanism for deformation twinning in magnesium

Deformation twinning is often mediated by partial dislocation activities at the twin boundary. Using molecular dynamics simulations, we have uncovered a new mechanism for the most commonly observed {1012}<101 1> deformation twinning in Mg and other hexagonal close-packed metals. Here the twin growth involves no definable dislocations at the twin boundary, and the twin orientational relationship can be established by local atomic shuffling, directly constructing the twin lattice from the parent lattice.

Atomic level structure in multicomponent bulk metallic glass

The atomic-level structure of a representative ternary Cu-Zr-Al bulk metallic glass (BMG) has been resolved. Cu- (and Al-) centered icosahedral clusters are identified as the basic local structural motifs. Compared with the Cu-Zr base binary, a small percentage of Al in the ternary BMG leads to dramatically increased population of full icosahedra and their spatial connectivity. The stabilizing effect of Al is not merely topological, but also has its origin in the electronic interactions and bond shortening.

Reversible twinning in pure aluminum

Twinning in metals is normally a permanent plastic deformation mechanism. Here we report reversible twinning in high stacking fault energy (SFE) aluminum. Twinning and spontaneous detwinning at the crack tip have been captured in situ during tensile straining under a transmission electron microscope. Both the in situ observation and the molecular dynamics simulations reveal a two-stage detwinning process. The high propensity for detwinning is due to the high SFE and the low frictional forces against the detwinning partial dislocations in Al. This discovery of reversible twinning has implications for the deformation of other high SFE materials.

Novel de novo BRCA1 mutation in a woman with early onset breast cancer

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Background: Germline mutations in BRCA1/2 account for a significant portion of hereditary breast/ovarian cancer. Mutation carriers usually have a family history of breast/ovarian cancer or early onset disease. Rarely, germline mutations are found only in the probands but not in any family members. Such de novo mutations have been reported in diseases such as hemophilia A, thalassaemia and familial adenomatous polyposis. De novo mutations in the BRCA1 or BRCA2 genes are rare and the few reported have been in BRCA2. Here, we describe de novo as well as novel mutation of the BRCA1 gene in a breast cancer patient. Methods: Blood DNA samples from a 30 year old Chinese woman with breast cancer and no family history of cancer was tested for a BRCA1/2 mutation by full gene sequencing and Multiple Ligation-dependent Probe Amplification (MLPA). Family members were analyzed for the same mutation. Paternity was determined by a set of highly polymorphic short tandem repeat (STR) markers. Results: Full gene sequencing found no deleterious mutation. MLPA revealed a large deletion of exons 1 to 12 of BRCA1 in the proband. MLPA performed on 5 family members: proband's mother and father (who were 1st degree relative- cousins), stepmother (mother's biological sister), 2 sisters (1, same parents; 1, same father and stepmother) found no similar deletion. By using a set of highly polymorphic STR markers, the proband's father and mother were confirmed to be her biological parents. Conclusions: We report a novel de novo BRCA1 deletion mutation encompassing exons 1 - 12 in a Chinese breast cancer patient of early onset with no family history. Identification of this large deletion confirms the importance of pursuing rearrangement testing if full gene sequencing fails to detect a point mutation or short insertion deletion. The mutation found in this study is de novo. This may simply be a random mutation event which occurred in the parents' germ cells during their lifetime which passed onto one of their offspring or maybe a result of gene inversion or splicing deficiency. The relations of such mutations with consanguineous marriage cannot be ruled out. Mutation screening is important in early onset breast cancer patients even if there is no family history.

No significant financial relationships to disclose.