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Sequencing studies of breast tumour cohorts have identified many prevalent mutations, but provide limited insight into the genomic diversity within tumours. Here we developed a whole-genome and exome single cell sequencing approach called nuc-seq that uses G2/M nuclei to achieve 91% mean coverage breadth. We applied this method to sequence single normal and tumour nuclei from an oestrogen-receptor-positive (ER + ) breast cancer and a triple-negative ductal carcinoma. In parallel, we performed single nuclei copy number profiling. Our data show that aneuploid rearrangements occurred early in tumour evolution and remained highly stable as the tumour masses clonally expanded. In contrast, point mutations evolved gradually, generating extensive clonal diversity. Using targeted single-molecule sequencing, many of the diverse mutations were shown to occur at low frequencies (<10%) in the tumour mass. Using mathematical modelling we found that the triple-negative tumour cells had an increased mutation rate (13.3×), whereas the ER + tumour cells did not. These findings have important implications for the diagnosis, therapeutic treatment and evolution of chemoresistance in breast cancer. To investigate genomic diversity within tumours, a new type of whole-genome and exome single cell sequencing has been developed using G2/M nuclei; the technique was used to sequence single nuclei from an oestrogen-positive breast cancer and a triple-negative ductal carcinoma—aneuploidy rearrangements emerged as early events in tumour formation and then point mutations evolved gradually over time. Cell heterogeneity in breast cancer Human breast cancers often display intratumour genomic heterogeneity, making clinical diagnosis difficult and complicating the interpretation of research results. This study tackles the problem using a newly developed whole-genome single-cell sequencing technique called nuc-seq that makes use of the natural genome duplication that occurs in the S phase of the cell cycle to achieve 91% mean coverage breadth. The method is applied to sequence single normal and tumour nuclei from an oestrogen-receptor-positive breast cancer and a triple-negative ductal carcinoma. Aneuploid rearrangements emerge as early events, and they remain stable during clonal expansion. In contrast, point mutations appear to evolve gradually, generating extensive clonal diversity. The data also show that no two single tumour cells are genetically identical, raising interesting questions as to the strict definition of a clone.

Understanding the cellular processes that underlie early lung adenocarcinoma (LUAD) development is needed to devise intervention strategies 1 . Here we studied 246,102 single epithelial cells from 16 early-stage LUADs and 47 matched normal lung samples. Epithelial cells comprised diverse normal and cancer cell states, and diversity among cancer cells was strongly linked to LUAD-specific oncogenic drivers. KRAS mutant cancer cells showed distinct transcriptional features, reduced differentiation and low levels of aneuploidy. Non-malignant areas surrounding human LUAD samples were enriched with alveolar intermediate cells that displayed elevated KRT8 expression (termed KRT8 + alveolar intermediate cells (KACs) here), reduced differentiation, increased plasticity and driver KRAS mutations. Expression profiles of KACs were enriched in lung precancer cells and in LUAD cells and signified poor survival. In mice exposed to tobacco carcinogen, KACs emerged before lung tumours and persisted for months after cessation of carcinogen exposure. Moreover, they acquired Kras mutations and conveyed sensitivity to targeted KRAS inhibition in KAC-enriched organoids derived from alveolar type 2 (AT2) cells. Last, lineage-labelling of AT2 cells or KRT8 + cells following carcinogen exposure showed that KACs are possible intermediates in AT2-to-tumour cell transformation. This study provides new insights into epithelial cell states at the root of LUAD development, and such states could harbour potential targets for prevention or intervention. Analyses of single epithelial cells from early-stage lung adenocarcinoma and normal lung identifies a population of intermediate cells that may have an increased likelihood of transforming to tumour cells after injury such as tobacco exposure.

The mechanism by which anti-cancer immunity shapes early carcinogenesis of lung adenocarcinoma (ADC) is unknown. In this study, we characterize the immune contexture of invasive lung ADC and its precursors by transcriptomic immune profiling, T cell receptor (TCR) sequencing and multiplex immunofluorescence (mIF). Our results demonstrate that anti-tumor immunity evolved as a continuum from lung preneoplasia, to preinvasive ADC, minimally-invasive ADC and frankly invasive lung ADC with a gradually less effective and more intensively regulated immune response including down-regulation of immune-activation pathways, up-regulation of immunosuppressive pathways, lower infiltration of cytotoxic T cells (CTLs) and anti-tumor helper T cells (Th), higher infiltration of regulatory T cells (Tregs), decreased T cell clonality, and lower frequencies of top T cell clones in later-stages. Driver mutations, chromosomal copy number aberrations (CNAs) and aberrant DNA methylation may collectively impinge host immune responses and facilitate immune evasion, promoting the outgrowth of fit subclones in preneoplasia into dominant clones in invasive ADC. The evolution of immune landscape in lung adenocarcinoma (ADC) is largely unknown. Here the authors use a cohort of resected invasive lung ADC and its precursors and show a gradual increase of immunosuppression and decrease of anti-tumor response associated with specific genomic and epigenetic features.

Breast cancer is one of the most commonly diagnosed cancers in women. While there are several effective therapies for breast cancer and important single gene prognostic/predictive markers, more than 40,000 women die from this disease every year. The increasing availability of large-scale genomic datasets provides opportunities for identifying factors that influence breast cancer survival in smaller, well-defined subsets. The purpose of this study was to investigate the genomic landscape of various breast cancer subtypes and its potential associations with clinical outcomes. We used statistical analysis of sequence data generated by the Cancer Genome Atlas initiative including somatic mutation load (SML) analysis, Kaplan–Meier survival curves, gene mutational frequency, and mutational enrichment evaluation to study the genomic landscape of breast cancer. We show that ER + , but not ER − , tumors with high SML associate with poor overall survival (HR = 2.02). Further, these high mutation load tumors are enriched for coincident mutations in both DNA damage repair and ER signature genes. While it is known that somatic mutations in specific genes affect breast cancer survival, this study is the first to identify that SML may constitute an important global signature for a subset of ER + tumors prone to high mortality. Moreover, although somatic mutations in individual DNA damage genes affect clinical outcome, our results indicate that coincident mutations in DNA damage response and signature ER genes may prove more informative for ER + breast cancer survival. Next generation sequencing may prove an essential tool for identifying pathways underlying poor outcomes and for tailoring therapeutic strategies.

The evolution of DNA methylome and methylation intra-tumor heterogeneity (ITH) during early carcinogenesis of lung adenocarcinoma has not been systematically studied. We perform reduced representation bisulfite sequencing of invasive lung adenocarcinoma and its precursors, atypical adenomatous hyperplasia, adenocarcinoma in situ and minimally invasive adenocarcinoma. We observe gradual increase of methylation aberrations and significantly higher level of methylation ITH in later-stage lesions. The phylogenetic patterns inferred from methylation aberrations resemble those based on somatic mutations suggesting parallel methylation and genetic evolution. De-convolution reveal higher ratio of T regulatory cells (Tregs) versus CD8 + T cells in later-stage diseases, implying progressive immunosuppression with neoplastic progression. Furthermore, increased global hypomethylation is associated with higher mutation burden, copy number variation burden and AI burden as well as higher Treg/CD8 ratio, highlighting the potential impact of methylation on chromosomal instability, mutagenesis and tumor immune microenvironment during early carcinogenesis of lung adenocarcinomas. It is known that invasive lung adenocarcinomas evolve from pre-cancerous dysplastic lesions. In this study, the authors show that evolution of pre-cancerous lesions is accompanied by DNA methylation alterations, and that global hypomethylation correlates with immune infiltration, mutational burden and copy number alterations.

Hepatocellular carcinoma (HCC) disproportionately affects Hispanic persons with higher age-specific incidence and increased mortality rates compared to non-Hispanic Whites. These high rates of incidence and mortality may be explained by the variation in risk factors. Given the high prevalence of type 2 diabetes mellitus (DM) among the Hispanic population, we aimed to assess the risk and prognosis of HCC in Mexican Americans with type 2 DM with consideration of treatment for DM. A case-control study of 241 Mexican American HCC patients and 500 healthy controls in Texas was conducted. Multivariable logistic regression analysis was performed to determine the association between type 2 DM and HCC risk while adjusting for other risk factors. Also, a restricted analysis of patients with type 2 DM was conducted to determine the effects of age at onset and duration of DM on HCC risk. Interactions among DM, heavy alcohol consumption, and viral hepatitis infection were examined. Overall survival was examined, and multivariable Cox proportional hazards regression analysis was performed for HCC patients with type 2 DM. The adjusted odds ratio (AOR) for DM was 2.74 (P < 0.01). Compared with patients who had DM for 2-10 years, those who had it for at least 20 years had an AOR of 4.60 ( = 0.04). Metformin use was associated with a reduced risk of death in HCC cases with type 2 DM, with a hazard ratio of 0.72 ( = 0.01) as compared with non-users. Our results demonstrate that type 2 DM was independently associated with increased risk of HCC among Mexican Americans. Metformin use was associated with improved survival among HCC patients with type 2 DM. Type 2 DM significantly increased the risk of HCC alone and in conjunction with other parameters of metabolic syndrome in the Mexican American population after adjusting for other risk factors.

Abstract Purpose of ReviewClonal hematopoiesis (CH) is an age-dependent process detectable using advanced sequencing technologies and is associated with multiple adverse health outcomes including cardiovascular disease and cancer. The purpose of this review is to summarize known causes of CH mutations and to identify key areas and considerations for future research on CH.Recent FindingsStudies have identified multiple potential causes of CH mutations including smoking, cancer therapies, cardiometabolic disease, inflammation, and germline risk factors. Additionally, large-scale studies have facilitated the identification of gene-specific effects of CH mutation risk factors that may have unique downstream health implications. For example, cancer therapies and sources of environmental radiation appear to cause CH through their impact on DNA damage repair genes.SummaryThere is a growing body of evidence defining risk factors for CH mutations. Standardization in the identification of CH mutations may have important implications for future research. Additional studies in underrepresented populations and their diverse environmental exposures are needed to facilitate broad public health impact of the study of CH mutations.

To identify genetic variants influencing plasma lipid concentrations, we first used genotype imputation and meta-analysis to combine three genome-wide scans totaling 8,816 individuals and comprising 6,068 individuals specific to our study (1,874 individuals from the FUSION study of type 2 diabetes and 4,184 individuals from the SardiNIA study of aging-associated variables) and 2,758 individuals from the Diabetes Genetics Initiative, reported in a companion study in this issue. We subsequently examined promising signals in 11,569 additional individuals. Overall, we identify strongly associated variants in eleven loci previously implicated in lipid metabolism ( ABCA1 , the APOA5-APOA4-APOC3-APOA1 and APOE-APOC clusters, APOB , CETP , GCKR , LDLR , LPL , LIPC , LIPG and PCSK9 ) and also in several newly identified loci (near MVK-MMAB and GALNT2 , with variants primarily associated with high-density lipoprotein (HDL) cholesterol; near SORT1 , with variants primarily associated with low-density lipoprotein (LDL) cholesterol; near TRIB1 , MLXIPL and ANGPTL3 , with variants primarily associated with triglycerides; and a locus encompassing several genes near NCAN , with variants strongly associated with both triglycerides and LDL cholesterol). Notably, the 11 independent variants associated with increased LDL cholesterol concentrations in our study also showed increased frequency in a sample of coronary artery disease cases versus controls.

Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modelling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis.

Background Mouse and human studies support the promise of dry beans to improve metabolic health and to lower cancer risk. In overweight/obese patients with a history of colorectal polyps or cancer, the Beans to Enrich the Gut microbiome vs. Obesity’s Negative Effects (BE GONE) trial will test whether and how an increase in the consumption of pre-cooked, canned dry beans within the context of usual diet and lifestyle can enhance the gut landscape to improve metabolic health and reduce cancer risk. Methods/design This randomized crossover trial is designed to characterize changes in (1) host markers spanning lipid metabolism, inflammation, and obesity-related cancer risk; (2) compositional and functional profiles of the fecal microbiome; and (3) host and microbial metabolites. With each subject serving as their own control, the trial will compare the participant’s usual diet with (intervention) and without (control) dry beans. Canned, pre-cooked dry beans are provided to participants and the usual diet continually assessed and monitored. Following a 4-week run-in and equilibration period, each participant provides a total of 5 fasting blood and 6 stool samples over a total period of 16 weeks. The intervention consists of a 2-week ramp-up of dry bean intake to 1 cup/d, which is then continued for an additional 6 weeks. Intra- and inter-individual outcomes are assessed across each crossover period with consideration of the joint or modifying effects of the usual diet and baseline microbiome. Discussion The BE GONE trial is evaluating a scalable dietary prevention strategy targeting the gut microbiome of high-risk patients to mitigate the metabolic and inflammatory effects of adiposity that influence colorectal cancer risk, recurrence, and survival. The overarching scientific goal is to further elucidate interactions between diet, the gut microbiome, and host metabolism. Improved understanding of the diet-microbiota interplay and effective means to target these relationships will be key to the future of clinical and public health approaches to cancer and other major diet- and obesity-related diseases. Trial registration This protocol is registered with the U.S. National Institutes of Health trial registry, ClinicalTrials.gov , under the identifier NCT02843425. First posted July 25, 2016; last verified January 25, 2019.