Citations

Background and objectives Presymptomatic testing is available for early diagnosis of hereditary autosomal dominant polycystic kidney disease (ADPKD). However, the complex ethical and psychosocial implications can make decision-making challenging and require an understanding of patients’ values, goals and priorities. This study aims to describe patient and caregiver beliefs and expectations regarding presymptomatic testing for ADPKD. Design, setting and participants 154 participants (120 patients and 34 caregivers) aged 18 years and over from eight centres in Australia, France and Korea participated in 17 focus groups. Transcripts were analysed thematically. Results We identified five themes: avoiding financial disadvantage (insecurity in the inability to obtain life insurance, limited work opportunities, financial burden); futility in uncertainty (erratic and diverse manifestations of disease limiting utility, taking preventive actions in vain, daunted by perplexity of results, unaware of risk of inheriting ADPKD); lacking autonomy and support in decisions (overwhelmed by ambiguous information, medicalising family planning, family pressures); seizing control of well-being (gaining confidence in early detection, allowing preparation for the future, reassurance in family resilience); and anticipating impact on quality of life (reassured by lack of symptoms, judging value of life with ADPKD). Conclusions For patients with ADPKD, presymptomatic testing provides an opportunity to take ownership of their health through family planning and preventive measures. However, these decisions can be wrought with tensions and uncertainty about prognostic implications, and the psychosocial and financial burden of testing. Healthcare professionals should focus on genetic counselling, mental health and providing education to patients’ families to support informed decision-making. Policymakers should consider the cost burden and risk of discrimination when informing government policies. Finally, patients are recommended to focus on self-care from an early age.

AbstractStaphylococcal enterotoxin B (SEB), which is produced by the major human pathogen, Staphylococcus aureus, represents a powerful superantigenic toxin and is considered a bioweapon. However, the contribution of SEB to S. aureus pathogenesis has never been directly demonstrated with genetically defined mutants in clinically relevant strains. Many isolates of the predominant Asian community-associated methicillin-resistant S. aureus lineage sequence type (ST) 59 harbor seb, implying a significant role of SEB in the observed hypervirulence of this lineage. We created an isogenic seb mutant in a representative ST59 isolate and assessed its virulence potential in mouse infection models. We detected a significant contribution of seb to systemic ST59 infection that was associated with a cytokine storm. Our results directly demonstrate that seb contributes to S. aureus pathogenesis, suggesting the value of including SEB as a target in multipronged antistaphylococcal drug development strategies. Furthermore, they indicate that seb contributes to fatal exacerbation of community-associated methicillin-resistant S. aureus infection.

Abstract Background Microsatellite instability (MSI) is a molecular phenotype characterized by the lengthening or shortening of tandem DNA repeats within the human genome. MSI phenomenon has been reported in various solid tumors as the consequence of DNA mismatch repair deficiency. It is generally associated with good prognosis and effective immunotherapy treatment. The current MSI tests are based on various methodologies, including immunohistochemistry, polymerase chain reactions, or next-generation sequencing (NGS). Each testing methodology has its own technical advantages, but they either fail at liquid biopsy specimen or implement complicated and expensive experimental interventions. Methods A designated analysis pipeline was developed individually for tissue biopsy and liquid biopsy to evaluate the stability of MSI sites within a NGS panel testing targeting over 400 genes at a common depth of coverage (<1000X for tissue biopsy and <5000X for liquid biopsy). The liquid biopsy algorithm implements a signal enhancing module based on a pool of normal samples to boost assay performance. We validated the tissue biopsy testing with an exploratory cohort of 90 gastrointestinal tract cancer patients. Retrospective review of over 10,000 pan-cancer patient-matched tissue-cfDNA sample pairs permitted a comprehensive evaluation of the liquid biopsy MSI testing performance. Results For tissue biopsy specimen validation, the assay system displayed 0.97 area-under-the-curve (AUC) in receiver operative characteristics (ROC) curve analysis against the comparator assay, out-performing publicly available MSI analysis software. Unfortunately, the tissue MSI analysis pipeline and publicly available software fails with less than 10% sensitivity and 0.55 AUC when applied to liquid biopsy specimen with the patient-matched tissue MSI status used as the gold standard. In contrast, the dedicated cfDNA analysis pipeline significantly boosted the assay performance to 0.73 without additional experimental interventions, such as wild-type allele depletion or molecular barcode. Conclusions MSI testing in liquid biopsy specimen remains challenging due to the low fraction of tumor originated cfDNA and consequently weak signal intensity. The implementation of the signal enhancing MSI analysis algorithm demonstrated high proficiency at improving the signal-to-noise ratio. This bioinformatics approach offered a cost-effective and non-invasive alternative for MSI testing without significantly modifying the NGS library preparation protocols. Citation Format: Xiangyuan Ma, Hua Bao, Xiaoling Tong, Zhili Chang, Xunbiao Liu, Xiuyan Zhang, Ryan S. Robetyore, Xue Wu, Yang W. Shao. Validation of a NGS-based MSI testing workflow in liquid biopsy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 730.

G 4 C 2 repeat–derived poly(GR) plays a key role in mediating TDP-43 mislocalization and aggregation in vitro and in vivo.

Abstract Background Hypothyroidism is known to be associated with adverse clinical outcomes in heart failure. The association between hypothyroidism and cardiac resynchronization therapy outcomes in patients with severe heart failure is not clear.Methods The study included 1,316 patients who received cardiac resynchronization therapy between 2002 and 2015. Baseline demographics and cardiac resynchronization therapy outcomes, including left ventricular ejection fraction, New York Heart Association class, appropriate implantable cardioverter-defibrillator therapy, and all-cause mortality, were collected from the electronic health record. Results Of the study cohort, 350 patients (26.6%) were classified as the hypothyroidism group. The median duration of follow-up was 3.6 years (interquartile range, 1.7-6.2). Hypothyroidism was not associated with a higher risk of all-cause mortality in patients receiving CRT for heart failure. The risk of appropriate implantable cardioverter-defibrillator therapy significantly increased in association with increased baseline thyroid-stimulating hormone level in the entire cohort (hazard ratio, 1.23 per 5mIU/L increase; 95% CI, 1.01-1.5; P=0.04) as well as in the hypothyroid group (hazard ratio, 1.44 per 5mIU/L increase; 95% CI, 1.13-1.84; P=0.004). Conclusions CRT improves cardiac function in hypothyroid patients. The ventricular arrhythmic events requiring ICD therapies are associated with baseline TSH level, which might be considered as an important biomarker to stratify the risk of sudden death for patients with heart failure and hypothyroidism.

Abstract The oncogenic transcription factor c-Maf has been proposed as an ideal therapeutic target for multiple myeloma (MM), but how to achieve it is still elusive. In the present study, we found the Otub1/c-Maf axis could be a potential target. Otub1, an OTU family deubiquitinase, was found to interact with c-Maf by mass spectrometry. Otub1 abrogates c-Maf K48-linked polyubiquitination, thus preventing its degradation and enhancing its transcriptional activity. Specifically, this deubiquitinating activity depends on its Lys71 and the N terminus but is independent of UBE2O, a known E2 of c-Maf. Otub1 promotes MM cell survival and MM tumor growth. In contrast, silence of Otub1 leads to c-Maf degradation and c-Maf-expressing MM cell apoptosis. Therefore, the Otub1/c-Maf axis could be a therapeutic target of MM. In order to explore this concept, we performed a c-Maf recognition element–driven luciferase-based screen against US Food and Drug Administration–approved drugs and natural products, from which the generic cardiac glycoside lanatoside C (LanC) is found to prevent c-Maf deubiquitination and induces its degradation by disrupting the interaction of Otub1 and c-Maf. Consequently, LanC inhibits c-Maf transcriptional activity, induces c-Maf-expressing MM cell apoptosis, and suppresses MM growth and prolongs overall survival of model mice, but without apparent toxicity. Therefore, the present study identifies Otub1 as a novel deubiquitinase of c-Maf and establishes that the Otub1/c-Maf axis is a potential therapeutic target for MM.

e19047 Background: Non-small cell lung cancer (NSCLC) is predominantly a disease of the elderly. Most patients (pts) present with incurable advanced disease, but chemotherapy for good performance status (PS) pts improves quality and quantity of life. Despite good PS, many elderly pts with metastatic NSCLC do not receive chemotherapy. This study compared treatment, outcomes, and survival in elderly vs younger pts with stage IV NSCLC. Methods: All analytic MCA Cancer Registry pts with stage IV NSCLC from 1998–2007 were retrospectively reviewed for type of therapy and outcome. Pts were analyzed by age: <75 vs ≥75 years old. Categorical variables were compared using chi-squared tests and survival was compared by Cox regression. Results: 344 pts with stage IV NSCLC were identified. 234 (68%) pts were <75 years old, and 110 pts (32%) were ≥75 years old. Median survival for all pts was 7 months. Among 302 pts with treatment data available, 60.8% of pts <75 years old received some form of systemic therapy (chemotherapy/targeted therapy) compared to only 32% of pts ≥ 75 years old (p <0.0001). Among pts with PS 0–1, pts <75 years old more frequently received systemic therapy than elderly patients (88.5% vs 32.1%, p<0.0001); whereas a difference was not evident in pts with PS 2–4 (34.1% vs 41.7%, p=0.49). Median survival in the <75 age group was 7 months vs. 3.4 months in the ≥75 age group (p=0.048). In the <75 age group, median survival was 12 months in pts who received chemotherapy vs. 2 months in the other or no treatment group (p<0.0001). In the elderly group, median survival was 10 months in the chemotherapy group vs. 2 months in the pts who received other or no treatment (p=0.0003). Thus, the median survival was significantly improved among the pts who received systemic therapy independent of age. Statistical significance persisted when stratifying by PS. Conclusions: Pts with stage IV NSCLC have improved survival with systemic therapy independent of age. Our results confirm that despite an improvement in survival similar to younger pts, elderly patients with metastatic NSCLC are often undertreated. Prospective trials should be designed to include metastatic NSCLC patients without age discrimination No significant financial relationships to disclose.

Background Sorbs2b (sorbin and SH3 domain‐containing 2b) was recently identified as a cardiomyopathy gene from a zebrafish mutagenesis screen. However, cardiac functions of its mammalian ortholog remain elusive. Methods and Results We conducted a detailed expression and subcellular localization analysis of Sorbs2 ortholog in mice and a phenotypic characterization in Sorbs2 knockout mice. Sorbs2 is highly expressed in the mouse heart and encodes an adhesion junction/desmosome protein that is mainly localized to the intercalated disc. A mutation with near complete depletion of the Sorbs2 protein in mice results in phenotypes characteristic of human arrhythmogenic cardiomyopathy (ACM), including right ventricular dilation, right ventricular dysfunction, spontaneous ventricular tachycardia, and premature death. Sorbs2 is required to maintain the structural integrity of intercalated disc. Its absence resulted in profound cardiac electrical remodeling with impaired impulse conduction and action potential derangements. Targeted sequencing of human patients with ACM identified 2 rare splicing variants classified as likely pathogenic were in 2 unrelated individuals with ACM from a cohort of 59 patients with ACM. Conclusions The Sorbs2 knockout mouse manifests several key features reminiscent of human ACM. Although the candidacy of SORBS2 as a new ACM‐susceptibility gene is supported by preliminary human genetics study, future validation in larger cohorts with ACM is needed.

Abstract Cellular senescence restrains the expansion of neoplastic cells through several layers of regulation, including epigenetic decoration of chromatin structure and functional modulation of bioactive components. Here we report that expression of the histone H3-specific demethylase KDM4 is upregulated in human stromal cells upon cellular senescence. In clinical oncology, upregulated KDM4 and diminished H3K9/H3K36 methylation are correlated with adverse survival of cancer patients post-chemotherapy. Global chromatin accessibility mapping via ATAC-seq and expression profiling through RNA-seq reveal extensive reorganization of chromosomes and spatiotemporal reprogramming of the transcriptomic landscape, events responsible for development of the senescence-associated secretory phenotype (SASP). Selectively targeting KDM4 dampens the SASP of senescent stromal cells and enhances the apoptotic index of cancer cells in the treatment-damaged tumor microenvironment (TME), together prolonging overall survival of experimental animals. Our study supports the dynamic change of H3K9/H3K36 methylation marks during cellular senescence, identifies an unusually permissive chromatin state, unmasks KDM4 as a key modulator of the SASP, and presents a novel therapeutic avenue to manipulate cellular senescence and curtail age-related pathologies.