NSABP FB-10: a phase Ib/II trial evaluating ado-trastuzumab emtansine (T-DM1) with neratinib in women with metastatic HER2-positive breast cancer.

BACKGROUND: We previously reported our phase Ib trial, testing the safety, tolerability, and efficacy of T-DM1 + neratinib in HER2-positive metastatic breast cancer patients. Patients with ERBB2 amplification in ctDNA had deeper and more durable responses. This study extends these observations with in-depth analysis of molecular markers and mechanisms of resistance in additional patients. METHODS: Forty-nine HER2-positive patients (determined locally) who progressed on-treatment with trastuzumab + pertuzumab were enrolled in this phase Ib/II study. Mutations and HER2 amplifications were assessed in ctDNA before (C1D1) and on-treatment (C2D1) with the Guardant360 assay. Archived tissue (TP0) and study entry biopsies (TP1) were assayed for whole transcriptome, HER2 copy number, and mutations, with Ampli-Seq, and centrally for HER2 with CLIA assays. Patient responses were assessed with RECIST v1.1, and Molecular Response with the Guardant360 Response algorithm. RESULTS: The ORR in phase II was 7/22 (32%), which included all patients who had at least one dose of study therapy. In phase I, the ORR was 12/19 (63%), which included only patients who were considered evaluable, having received their first scan at 6 weeks. Central confirmation of HER2-positivity was found in 83% (30/36) of the TP0 samples. HER2-amplified ctDNA was found at C1D1 in 48% (20/42) of samples. Patients with ctHER2-amp versus non-amplified HER2 ctDNA determined in C1D1 ctDNA had a longer median progression-free survival (PFS): 480 days versus 60 days (P = 0.015). Molecular Response scores were significantly associated with both PFS (HR 0.28, 0.09-0.90, P = 0.033) and best response (P = 0.037). All five of the patients with ctHER2-amp at C1D1 who had undetectable ctDNA after study therapy had an objective response. Patients whose ctHER2-amp decreased on-treatment had better outcomes than patients whose ctHER2-amp remained unchanged. HER2 RNA levels show a correlation to HER2 CLIA IHC status and were significantly higher in patients with clinically documented responses compared to patients with progressive disease (P = 0.03). CONCLUSIONS: The following biomarkers were associated with better outcomes for patients treated with T-DM1 + neratinib: (1) ctHER2-amp (C1D1) or in TP1; (2) Molecular Response scores; (3) loss of detectable ctDNA; (4) RNA levels of HER2; and (5) on-treatment loss of detectable ctHER2-amp. HER2 transcriptional and IHC/FISH status identify HER2-low cases (IHC 1+ or IHC 2+ and FISH negative) in these heavily anti-HER2 treated patients. Due to the small number of patients and samples in this study, the associations we have shown are for hypothesis generation only and remain to be validated in future studies. Clinical Trials registration NCT02236000.

PIGA mutations and glycosylphosphatidylinositol anchor dysregulation in polyposis-associated duodenal tumorigenesis.

The pathogenesis of duodenal tumours in the inherited tumour syndromes Familial Adenomatous Polyposis (FAP) and MUTYH-associated Polyposis (MAP) is poorly understood. This study aimed to identify genes that are significantly mutated in these tumours and to explore the effects of these mutations. Whole exome and whole transcriptome sequencing identified recurrent somatic coding variants of PIGA in 19/70 (27%) FAP and MAP duodenal adenomas, and further confirmed the established driver roles for APC and KRAS. PIGA catalyses the first step in glycosylphosphatidylinositol (GPI) anchor biosynthesis. Flow cytometry of PIGA-mutant adenoma-derived and CRISPR-edited duodenal organoids confirmed loss of GPI anchors in duodenal epithelial cells and transcriptional profiling of duodenal adenomas revealed transcriptional signatures associated with loss of PIGA. Implications: PIGA somatic mutation in duodenal tumours from patients with FAP and MAP and loss of membrane GPI-anchors may present new opportunities for understanding and intervention in duodenal tumorigenesis.

The Effects of Previous Experiences of Healthcare Discrimination on HIV Intervention Outcomes.

Although several healthcare interventions have been developed to address HIV among young Black/African American men who have sex with men (YBMSM), the HIV epidemic in the United States continues to disproportionately burden this population. The current study examines previous healthcare discrimination and how it affects HIV intervention delivery. One hundred seventy-two YBMSM participated in the Peer Promotion of Wellness and Enhanced Linkage to Resources (PPOWER) project, which used a short, multi-faceted, community-level intervention based on Community Peers Reaching Out and Modeling Intervention Strategies (Community PROMISE). Data were collected at baseline, a 45-day follow up, and a 90-day follow up. Generalized Estimating Equations (GEE) were used to examine the effects of previous healthcare discrimination on outcomes related to HIV testing, alcohol and drug use, and sexual behaviors. Previous healthcare discrimination was found to moderate the relationship between time and intentions to test for HIV, perceptions of sexual risk, problem marijuana use, and problem other drug use, such that those who had experienced more healthcare discrimination showed greater improvements over time compared to those who had experienced less healthcare discrimination. The results of the current study suggest that a community-level peer intervention, in combination with a component to promote cultural competency and address prior experiences of discrimination in healthcare settings, may be highly effective for people who have experienced a barrier in their continuum of care as a result of racial discrimination.

Genomic Landscape of Lynch Syndrome Colorectal Neoplasia Identifies Shared Mutated Neoantigens for Immunoprevention.

BACKGROUND & AIMS: Lynch syndrome (LS) carriers develop mismatch repair-deficient neoplasia with high neoantigen (neoAg) rates. No detailed information on targetable neoAgs from LS precancers exists, which is crucial for vaccine development and immune-interception strategies. We report a focused somatic mutation and frameshift-neoAg landscape of microsatellite loci from colorectal polyps without malignant potential (PWOMP), precancers, and early-stage cancers in LS carriers. METHODS: We generated paired whole-exome and transcriptomic sequencing data from 8 colorectal PWOMP, 41 precancers, 8 advanced precancers, and 12 early-stage cancers of 43 LS carriers. A computational pipeline was developed to predict, rank, and prioritize the top 100 detected mutated neoAgs that were validated in vitro using ELISpot and tetramer assays. RESULTS: Mutation calling revealed >10 mut/Mb in 83% of cancers, 63% of advanced precancers, and 20% of precancers. Cancers displayed an average of 616 MHC-I neoAgs/sample, 294 in advanced precancers, and 107 in precancers. No neoAgs were detected in PWOMP. A total of 65% of our top 100 predicted neoAgs were immunogenic in vitro, and were present in 92% of cancers, 50% of advanced precancers, and 29% of precancers. We observed increased levels of naïve CD8+ and memory CD4+ T cells in mismatch repair-deficient cancers and precancers via transcriptomics analysis. CONCLUSIONS: Shared frameshift-neoAgs are generated within unstable microsatellite loci at initial stages of LS carcinogenesis and can induce T-cell responses, generating opportunities for vaccine development, targeting LS precancers and early-stage cancers.

Healthcare discrimination, anticipated HIV stigma, and income as predictors of HIV testing among a community sample of YBMSM.

Young Black men who have sex with men (YBMSM) are at particular risk for HIV, and knowing one's HIV status is key to preventing new HIV infections. Data were derived from a community-based study involving 250 YBMSM to examine the relationships between race-based discrimination experienced in healthcare settings, anticipated HIV stigma, household income and lifetime HIV testing. Lifetime HIV testing was regressed on racial discrimination in healthcare settings, anticipated HIV stigma, and income, and a significant 3-way interaction was found. To help interpret the 3-way interaction, lifetime HIV testing was regressed on racial discrimination in healthcare settings and anticipated HIV stigma in two separate models; with low-income and higher-income YBMSM. Anticipated HIV stigma was found to predict HIV testing among low-income YBMSM. A significant interaction was detected such that low-income YBMSM with low levels of anticipated HIV stigma were more likely to get tested for HIV regardless of experiences with healthcare discrimination, while low-income YBMSM who reported greater anticipated HIV stigma and more experiences of healthcare discrimination were less likely to get tested for HIV. Understanding the complexity of potential barriers is crucial for developing interventions to increase HIV testing within this population.

A Community-Defined Approach to Address Trauma Among Cambodian Immigrants and Refugees.

Asian American and Pacific Islanders are one of the fastest growing and most diverse groups in the United States. Yet, they are often aggregated as a single group, masking within-group differences in rates of disease and demographic characteristics commonly associated with elevated health risk. While more than four decades have passed since the Khmer Rouge genocide, Cambodians continue to experience trauma-related psychiatric disorders, including post-traumatic stress disorder and major depression. Funded by the California Department of Public Health Office of Health Equity, the Community Wellness Program (CWP) aimed to reduce mental health disparities among Cambodians in Long Beach and Santa Ana, California, using community-defined approaches. The 6-month program comprised community outreach, educational workshops, strengths-based case management, and social and spiritual activities. Our study aimed to examine the effects of the CWP on trauma symptoms. Program evaluation followed an incomplete stepped wedge waitlist design with two study arms. A linear mixed models analysis revealed that participants reported fewer trauma symptoms as a result of participation in the CWP and that participants experienced fewer symptoms over time. This is an especially important finding, as trauma can lead to long-term individual health effects and to social and health repercussions on an entire cultural group by way of intergenerational trauma. As the number of refugees and displaced individuals continues to grow, there is an urgent need for programs such as the CWP to prevent the lasting effects of trauma.

A comprehensive medical Spanish curriculum model: the Vida Medical Spanish Curriculum.

INTRODUCTION: Racial and language disparities in the United States healthcare system have long undermined the quality of care provided to minority patients. With the projected growth of the Hispanic population, there is an urgent need for medical schools to integrate high-quality medical Spanish and cultural competency content. We propose a comprehensive medical Spanish curriculum aligned with the preclinical curriculum as a solution to these issues. The primary goal of this study is to demonstrate the effectiveness of a clinically focused, culturally competent medical Spanish program and advocate for its widespread adoption in medical institutions nationwide. METHODS: The study utilized the Kirkpatrick Model to evaluate the success of the medical Spanish curriculum. A total of 111 medical students voluntarily enrolled in the medical Spanish course. Out of these students, 47 completed the final evaluation, which included a Spanish Objective Structured Clinical Examination and a 40-question Multiple-Choice Exam assessing the integration of Spanish language skills and cultural competency. Both assessment methods took place in clinical skills facilities. Descriptive statistics summarized exam results, and two-tailed t-tests compared mean exam scores between students of different proficiency levels. RESULTS AND DISCUSSION: Students achieved a mean score of over 80% on all components of the Spanish Objective Structured Clinical Examination and the Multiple-Choice Exam. Survey data suggest that students felt able to communicate in Spanish with patients after completing the course series. The study also provides a model for a medical Spanish curriculum that applies expert-recommended best practices to meet the needs of Hispanic patient populations. LIMITATIONS AND CONCLUSIONS: Students who sat for the OSCE and MCE were self-selected. Baseline data on student perceptions and Spanish competency are not sufficient for making comparisons.

Plasma tumor mutation burden is associated with clinical benefit in patients with non-small cell lung cancer treated with anti-programmed death-1 monotherapy.

Background: The clinical utility of plasma tumor mutational burden (pTMB) requires further validation. Herein, the pTMB and genetic alterations were investigated as predictive biomarkers for anti-PD-1 monotherapy outcome in metastatic non-small cell lung cancer (NSCLC). Methods: The GuardantOMNI panel (Guardant Health) was used to identify pTMB and genetic alterations. Data from 99 patients with metastatic NSCLC treated with pembrolizumab or nivolumab in first-, second-, or third-line settings between June 2016 and December 2020 were collected. Associations between pTMB and clinical benefit rate (CBR, stable disease ⩾6 months or partial response), progression-free survival (PFS), and overall survival (OS) were assessed. Results: Median pTMB in 84 patients was 10.8 mutations/megabase (mut/Mb). Histological analyses revealed that 61 and 36% of the patients had adenocarcinomas and squamous NSCLC, respectively. Most patients were treated with nivolumab (74%) and most anti-PD-1 agents were administered as second-line treatment (70%). The median follow-up duration was of 10.9 months (range, 0.2-40.7). Patients with high pTMB (⩾19 mut/Mb) had a higher CBR (69%) compared with low pTMB patients (33%; p = 0.01). ARID1A (p = 0.007) and either ERBB2 or KIT mutations (p = 0.012) were positive and negative determinants, respectively, for clinical benefit. Multivariate analysis further showed that high pTMB was an independent predictive biomarker for both PFS [hazard ratio (HR) = 0.44, 95% confidence interval (CI): 0.22-0.88, p = 0.02] and OS (HR = 0.37, 95% CI: 0.18-0.76, p = 0.007). Conclusion: High pTMB (⩾19 mut/Mb) is significantly associated with CBR in patients with NSCLC treated with anti-PD-1 agents.

A whole-exome case-control association study to characterize the contribution of rare coding variation to pancreatic cancer risk.

Pancreatic cancer is a deadly disease that accounts for approximately 5% of cancer deaths worldwide, with a dismal 5-year survival rate of 10%. Known genetic risk factors explain only a modest proportion of the heritable risk of pancreatic cancer. We conducted a whole-exome case-control sequencing study in 1,591 pancreatic cancer cases and 2,134 cancer-free controls of European ancestry. In our gene-based analysis, ATM ranked first, with a genome-wide significant p value of 1 × 10-8. The odds ratio for protein-truncating variants in ATM was 24, which is substantially higher than prior estimates, although ours includes a broad 95% confidence interval (4.0-1000). SIK3 was the second highest ranking gene (p = 3.84 × 10-6, false discovery rate or FDR = 0.032). We observed nominally significant association signals in several genes of a priori interest, including BRCA2 (p = 4.3 × 10-4), STK11 (p = 0.003), PALB2 (p = 0.019), and TP53 (p = 0.037), and reported risk estimates for known pathogenic variants and variants of uncertain significance (VUS) in these genes. The rare variants in established susceptibility genes explain approximately 24% of log familial relative risk, which is comparable to the contribution from established common susceptibility variants (17%). In conclusion, this study provides new insights into the genetic susceptibility of pancreatic cancer, refining rare variant risk estimates in known pancreatic cancer susceptibility genes and identifying SIK3 as a novel candidate susceptibility gene. This study highlights the prominent importance of ATM truncating variants and the underappreciated role of VUS in pancreatic cancer etiology.

Transcriptomic-Assisted Immune and Neoantigen Profiling in Premalignancy.

Immune-based cancer therapies such as checkpoint inhibitors (CPI) and vaccines have been increasingly studied across different cancer types. Response to such therapies depends on a number of factors such as mutational burden, neoantigen load, presence of tumor infiltrating lymphocytes, among others. Next-generation sequencing (NGS) technologies are particularly attractive to interrogate the immune response compared to traditional assays such as qRT-PCR and immunohistochemistry (IHC) because they enable the discovery of neoantigens and simultaneous profiling of immune infiltration using gene expression on a large scale. Current approaches in immune profiling utilizes whole-exome sequencing (WES) for human leukocyte allele (HLA) typing and neoantigen predictions, and RNA sequencing (RNA-seq) for filtering unexpressed neoantigens and inferring immune infiltration. They have been successfully applied to the tumor setting as there is abundant sample material to perform both experiments. However, premalignant specimens are often much smaller compared to tumors. Therefore, there is a need to explore the viability of adopting a single approach for immune, neoantigen, and mutation profiling. Here, we describe our workflow of using RNA-seq to analyze mutational burden, neoantigen load, and immune expression profile.

Chromosomal imbalances detected via RNA-sequencing in 28 cancers.

MOTIVATION: RNA-sequencing (RNA-seq) of tumor tissue is typically only used to measure gene expression. Here, we present a statistical approach that leverages existing RNA-seq data to also detect somatic copy number alterations (SCNAs), a pervasive phenomenon in human cancers, without a need to sequence the corresponding DNA. RESULTS: We present an analysis of 4942 participant samples from 28 cancers in The Cancer Genome Atlas (TCGA), demonstrating robust detection of SCNAs from RNA-seq. Using genotype imputation and haplotype information, our RNA-based method had a median sensitivity of 85% to detect SCNAs defined by DNA analysis, at high specificity (∼95%). As an example of translational potential, we successfully replicated SCNA features associated with breast cancer subtypes. Our results credential haplotype-based inference based on RNA-seq to detect SCNAs in clinical and population-based settings. AVAILABILITY AND IMPLEMENTATION: The analyses presented use the data publicly available from TCGA Research Network (http://cancergenome.nih.gov/). See Methods for details regarding data downloads. hapLOHseq software is freely available under The MIT license and can be downloaded from http://scheet.org/software.html. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Chromatin state dynamics confers specific therapeutic strategies in enhancer subtypes of colorectal cancer.

OBJECTIVE: Enhancer aberrations are beginning to emerge as a key epigenetic feature of colorectal cancers (CRC), however, a comprehensive knowledge of chromatin state patterns in tumour progression, heterogeneity of these patterns and imparted therapeutic opportunities remain poorly described. DESIGN: We performed comprehensive epigenomic characterisation by mapping 222 chromatin profiles from 69 samples (33 colorectal adenocarcinomas, 4 adenomas, 21 matched normal tissues and 11 colon cancer cell lines) for six histone modification marks: H3K4me3 for Pol II-bound and CpG-rich promoters, H3K4me1 for poised enhancers, H3K27ac for enhancers and transcriptionally active promoters, H3K79me2 for transcribed regions, H3K27me3 for polycomb repressed regions and H3K9me3 for heterochromatin. RESULTS: We demonstrate that H3K27ac-marked active enhancer state could distinguish between different stages of CRC progression. By epigenomic editing, we present evidence that gains of tumour-specific enhancers for crucial oncogenes, such as ASCL2 and FZD10, was required for excessive proliferation. Consistently, combination of MEK plus bromodomain inhibition was found to have synergistic effects in CRC patient-derived xenograft models. Probing intertumour heterogeneity, we identified four distinct enhancer subtypes (EPIgenome-based Classification, EpiC), three of which correlate well with previously defined transcriptomic subtypes (consensus molecular subtypes, CMSs). Importantly, CMS2 can be divided into two EpiC subgroups with significant survival differences. Leveraging such correlation, we devised a combinatorial therapeutic strategy of enhancer-blocking bromodomain inhibitors with pathway-specific inhibitors (PARPi, EGFRi, TGFßi, mTORi and SRCi) for EpiC groups. CONCLUSION: Our data suggest that the dynamics of active enhancer underlies CRC progression and the patient-specific enhancer patterns can be leveraged for precision combination therapy.

Project Unmute: A Digital Music Program Delivered by Adolescent Musicians to Older Adults with Cognitive Decline.

Effective intergenerational music programming has the power to positively influence the current lives of the millions of older adults who are experiencing Alzheimer's disease and dementia, as well as to support the confidence of the newest generation of young musicians. To explore this potential, we designed a digital, intergenerational music program delivered by adolescent musicians to older adults with cognitive decline. This program utilized songs preferred by the older adults and an interactive activity that engaged the two generations. We believe this type of easily scalable programming could support older adults and young musicians, as well as promote new intergenerational relationships.

Combination of Sulindac and Bexarotene for Prevention of Intestinal Carcinogenesis in Familial Adenomatous Polyposis.

Familial adenomatous polyposis (FAP) is a hereditary colorectal cancer syndrome, which results in the development of hundreds of adenomatous polyps carpeting the gastrointestinal tract. NSAIDs have reduced polyp burden in patients with FAP and synthetic rexinoids have demonstrated the ability to modulate cytokine-mediated inflammation and WNT signaling. This study examined the use of the combination of an NSAID (sulindac) and a rexinoid (bexarotene) as a durable approach for reducing FAP colonic polyposis to prevent colorectal cancer development. Whole transcriptomic analysis of colorectal polyps and matched normal mucosa in a cohort of patients with FAP to identify potential targets for prevention in FAP was performed. Drug-dose synergism of sulindac and bexarotene in cell lines and patient-derived organoids was assessed, and the drug combination was tested in two different mouse models. This work explored mRNA as a potential predictive serum biomarker for this combination in FAP. Overall, transcriptomic analysis revealed significant activation of inflammatory and cell proliferation pathways. A synergistic effect of sulindac (300 µmol/L) and bexarotene (40 µmol/L) was observed in FAP colonic organoids with primary targeting of polyp tissue compared with normal mucosa. This combination translated into a significant reduction in polyp development in ApcMin/+ and ApcLoxP/+-Cdx2 mice. Finally, the reported data suggest miRNA-21 could serve as a predictive serum biomarker for polyposis burden in patients with FAP. These findings support the clinical development of the combination of sulindac and bexarotene as a treatment modality for patients with FAP. PREVENTION RELEVANCE: This study identified a novel chemopreventive regimen combining sulindac and bexarotene to reduce polyposis in patients with FAP using in silico tools, ex vivo, and in vivo models. This investigation provides the essential groundwork for moving this drug combination forward into a clinical trial.

Telomere dysfunction instigates inflammation in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic inflammatory condition driven by diverse genetic and nongenetic programs that converge to disrupt immune homeostasis in the intestine. We have reported that, in murine intestinal epithelium with telomere dysfunction, DNA damage-induced activation of ataxia-telangiectasia mutated (ATM) results in ATM-mediated phosphorylation and activation of the YAP1 transcriptional coactivator, which in turn up-regulates pro-IL-18, a pivotal immune regulator in IBD pathogenesis. Moreover, individuals with germline defects in telomere maintenance genes experience increased occurrence of intestinal inflammation and show activation of the ATM/YAP1/pro-IL-18 pathway in the intestinal epithelium. Here, we sought to determine the relevance of the ATM/YAP1/pro-IL-18 pathway as a potential driver of IBD, particularly older-onset IBD. Analysis of intestinal biopsy specimens and organoids from older-onset IBD patients documented the presence of telomere dysfunction and activation of the ATM/YAP1/precursor of interleukin 18 (pro-IL-18) pathway in the intestinal epithelium. Employing intestinal organoids from healthy individuals, we demonstrated that experimental induction of telomere dysfunction activates this inflammatory pathway. In organoid models from ulcerative colitis and Crohn's disease patients, pharmacological interventions of telomerase reactivation, suppression of DNA damage signaling, or YAP1 inhibition reduced pro-IL-18 production. Together, these findings support a model wherein telomere dysfunction in the intestinal epithelium can initiate the inflammatory process in IBD, pointing to therapeutic interventions for this disease.

Resolving the Spatial and Cellular Architecture of Lung Adenocarcinoma by Multiregion Single-Cell Sequencing.

Little is known of the geospatial architecture of individual cell populations in lung adenocarcinoma (LUAD) evolution. Here, we perform single-cell RNA sequencing of 186,916 cells from five early-stage LUADs and 14 multiregion normal lung tissues of defined spatial proximities from the tumors. We show that cellular lineages, states, and transcriptomic features geospatially evolve across normal regions to LUADs. LUADs also exhibit pronounced intratumor cell heterogeneity within single sites and transcriptional lineage-plasticity programs. T regulatory cell phenotypes are increased in normal tissues with proximity to LUAD, in contrast to diminished signatures and fractions of cytotoxic CD8+ T cells, antigen-presenting macrophages, and inflammatory dendritic cells. We further find that the LUAD ligand-receptor interactome harbors increased expression of epithelial CD24, which mediates protumor phenotypes. These data provide a spatial atlas of LUAD evolution, and a resource for identification of targets for its treatment. SIGNIFICANCE: The geospatial ecosystem of the peripheral lung and early-stage LUAD is not known. Our multiregion single-cell sequencing analyses unravel cell populations, states, and phenotypes in the spatial and ecologic evolution of LUAD from the lung that comprise high-potential targets for early interception.This article is highlighted in the In This Issue feature, p. 2355.

Circulating Plasma Tumor DNA Is Superior to Plasma Tumor RNA Detection in Ewing Sarcoma Patients: ptDNA and ptRNA in Ewing Sarcoma.

The detection of tumor-specific nucleic acids from blood increasingly is being used as a method of liquid biopsy and minimal residual disease detection. However, achieving high sensitivity and high specificity remains a challenge. Here, we perform a direct comparison of two droplet digital PCR (ddPCR)-based detection methods, circulating plasma tumor RNA and circulating plasma tumor DNA (ptDNA), in blood samples from newly diagnosed Ewing sarcoma patients. First, we developed three specific ddPCR-based assays to detect EWS-FLI1 or EWS-ERG fusion transcripts, which naturally showed superior sensitivity to DNA detection on in vitro control samples. Next, we identified the patient-specific EWS-FLI1 or EWS-ERG breakpoint from five patient tumor samples and designed ddPCR-based, patient-specific ptDNA assays for each patient. These patient-specific assays show that although plasma tumor RNA can be detected in select newly diagnosed patients, positive results are low and statistically unreliable compared with ptDNA assays, which reproducibly detect robust positive results across most patients. Furthermore, the unique disease biology of Ewing sarcoma enabled us to show that most cell-free RNA is not tumor-derived, although cell-free-DNA burden is affected strongly by tumor-derived DNA burden. Here, we conclude that, even with optimized highly sensitive and specific assays, tumor DNA detection is superior to RNA detection in Ewing sarcoma patients.

Single-Cell Expression Landscape of SARS-CoV-2 Receptor ACE2 and Host Proteases in Normal and Malignant Lung Tissues from Pulmonary Adenocarcinoma Patients.

The novel coronavirus SARS-CoV-2 is the causative agent of the COVID-19 pandemic. Severely symptomatic COVID-19 is associated with lung inflammation, pneumonia, and respiratory failure, thereby raising concerns of elevated risk of COVID-19-associated mortality among lung cancer patients. Angiotensin-converting enzyme 2 (ACE2) is the major receptor for SARS-CoV-2 entry into lung cells. The single-cell expression landscape of ACE2 and other SARS-CoV-2-related genes in pulmonary tissues of lung cancer patients remains unknown. We sought to delineate single-cell expression profiles of ACE2 and other SARS-CoV-2-related genes in pulmonary tissues of lung adenocarcinoma (LUAD) patients. We examined the expression levels and cellular distribution of ACE2 and SARS-CoV-2-priming proteases TMPRSS2 and TMPRSS4 in 5 LUADs and 14 matched normal tissues by single-cell RNA-sequencing (scRNA-seq) analysis. scRNA-seq of 186,916 cells revealed epithelial-specific expression of ACE2, TMPRSS2, and TMPRSS4. Analysis of 70,030 LUAD- and normal-derived epithelial cells showed that ACE2 levels were highest in normal alveolar type 2 (AT2) cells and that TMPRSS2 was expressed in 65% of normal AT2 cells. Conversely, the expression of TMPRSS4 was highest and most frequently detected (75%) in lung cells with malignant features. ACE2-positive cells co-expressed genes implicated in lung pathobiology, including COPD-associated HHIP, and the scavengers CD36 and DMBT1. Notably, the viral scavenger DMBT1 was significantly positively correlated with ACE2 expression in AT2 cells. We describe normal and tumor lung epithelial populations that express SARS-CoV-2 receptor and proteases, as well as major host defense genes, thus comprising potential treatment targets for COVID-19 particularly among lung cancer patients.