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Detailed information of candidate driver mutations

Supplementary Materials and Methods Supplementary Table S1 - Sequencing coverage for tumor regions and germline samples Supplementary Table S2 - Clinical characteristics of patients with EAC Supplementary Table S4 - Annotation of chromosomal segments that overlap with TCGA ESCA recurrent amplifications and tumor regions in our EAC cohort Supplementary Figure S1 - Mutations identified using M-seq compared with a single biopsy Supplementary Figure S2 - Relationship of intratumor heterogeneity and response to NAC treatment Supplementary Figure S3 - Tumor Phylograms Supplementary Figure S4 - Copy number events lead to mutational heterogeneity Supplementary Figure S5 - Heatmap of the all driver mutations identified across all tumor regions Supplementary Figure S6 - Driver mutations identified using M-seq compared with a single biopsy Supplementary Figure S7 - Copy number states across the genome for each tumor region Supplementary Figure S8 - Chromosome view of chromosome 19, tumor sample EAC017, region R1, demonstrating chromothripsis Supplementary Figure S9 - wGII scores for the TCGA ESCA cohort and M-seq EAC cohort Supplementary Figure S10 - The trinucleotide context for temporally dissected combined EAC cohort Supplementary Figure S11 - Assessing copy number heterogeneity using a minimum consecutive segment method

Other than an association with HPV infection, little is known about the genetic alterations determining the development of penile cancer. Although penile cancer is rare in the developed world, it presents a significant burden in developing countries. Here, we report the findings of whole-exome sequencing (WES) to determine the somatic mutational landscape of penile cancer. WES was performed on penile cancer and matched germline DNA from 27 patients undergoing surgical resection. Targeted resequencing of candidate genes was performed in an independent 70 patient cohort. Mutation data were also integrated with DNA methylation and copy-number information from the same patients. We identified an HPV-associated APOBEC mutation signature and an NpCpG signature in HPV-negative disease. We also identified recurrent mutations in the novel penile cancer tumor suppressor genes CSN1(GPS1) and FAT1. Expression of CSN1 mutants in cells resulted in colocalization with AGO2 in cytoplasmic P-bodies, ultimately leading to the loss of miRNA-mediated gene silencing, which may contribute to disease etiology. Our findings represent the first comprehensive analysis of somatic alterations in penile cancer, highlighting the complex landscape of alterations in this malignancy. Cancer Res; 76(16); 4720–7. ©2016 AACR.

Supplementary methods

Supplementary Table 1. A)Patient details for Fresh Frozen test cohort, B) Patient details for validation cohort. Supplementary Figure 1. APOBEC mutation fraction of across multiple cancer types. Supplementary Figure 2. DNA methylation. Supplementary Figure 3. Candidate PeCa driver mutations. Supplementary Figure 4. Schematic of FAT1 is shown with locations of mutations and ethylation states of PeCa and normal penile tissue across the canonical FAT1 gene. Supplementary Figure 5. A) Example plot of Copy Number Alterations (CNA) in penile cancers, 450K methylation profiles for penile cancer and normal squamous epithelium, and output from GISTIC showing the frequency and significance of CNAs.

CDK7 has a central role in promoting cellular proliferation, through the activation of the mitotic CDKs, and by driving global gene expression, through targeting RNA polymerase II. Several recently developed CDK7 inhibitors (CDK7i) have been shown to be non-toxic and to limit tumour growth for a number of cancer cell types and are now in Phase I/II clinical trials. However, the mechanisms underlying the sensitivity of particular cancer cells to CDK7 inhibition remain largely unknown.To improve the outcome of individual patients and increase the chances of successful CDK7i approval, we assessed which fundamental cellular processes determine sensitivity to CDK7 inhibition, using the highly specific CDK7 inhibitor ICEC0942. Our data shows that selective CDK7 inhibition acutely arrests cells in the G1 phase of the cell cycle, which over time leads to senescence. Through a genome-wide CRISPR knock-out chemogenetic screen we identified active mTOR (mammalian target of rapamycin) signalling, as an important determinant of ICEC0942-induced senescence and show that a cancer-associated mutation that promotes cell growth can increase sensitivity to ICEC0942. Our work indicates that cellular growth is an important predictive marker for sensitivity to CDK7i.

Approximately 50% of patients with early-stage non-small-cell lung cancer (NSCLC) who undergo surgery with curative intent will relapse within 5 years1,2. Detection of circulating tumor cells (CTCs) at the time of surgery may represent a tool to identify patients at higher risk of recurrence for whom more frequent monitoring is advised. Here we asked whether CellSearch-detected pulmonary venous CTCs (PV-CTCs) at surgical resection of early-stage NSCLC represent subclones responsible for subsequent disease relapse. PV-CTCs were detected in 48% of 100 patients enrolled into the TRACERx study3, were associated with lung-cancer-specific relapse and remained an independent predictor of relapse in multivariate analysis adjusted for tumor stage. In a case study, genomic profiling of single PV-CTCs collected at surgery revealed higher mutation overlap with metastasis detected 10 months later (91%) than with the primary tumor (79%), suggesting that early-disseminating PV-CTCs were responsible for disease relapse. Together, PV-CTC enumeration and genomic profiling highlight the potential of PV-CTCs as early predictors of NSCLC recurrence after surgery. However, the limited sensitivity of PV-CTCs in predicting relapse suggests that further studies using a larger, independent cohort are warranted to confirm and better define the potential clinical utility of PV-CTCs in early-stage NSCLC.

Patient-derived xenograft (PDX) models have become important models in cancer biology. They are thought to mimic tumor biology more closely than traditional cell lines as a consequence of their in vivo heterocellularity and cell-matrix interactions, their 3D architecture and their relatively recent derivation. The genomic fidelity of PDXs is integral to their applications in both basic research and in translational medicine. We derived multi-region PDX models from patients enrolled in TRACERx - a study of the evolutionary dynamics of non-small cell lung cancer (NSCLC) that uses a multi-region deep whole-exome sequencing (WES) approach - using more extensive spatial sampling to better understand the histological and genomic fidelity of the PDX approach. We transplanted regional NSCLC tumor tissue subcutaneously into immunocompromised NSG mice. 134 regions were attempted, resulting in 60 passagable xenografts (44.8%). Of these, 44 regional xenografts (32.8% of all regions) were NSCLC-derived, while 16 (11.9% of all regions) were B-cell lymphoproliferative disease. Multi-region sampling revealed heterogeneous success of PDX derivation between regions within individual patient tumors. There was correlation between PDX derivation and tumor purity by WES. Overall, NSCLC PDX models were established for 22 patients (50%; range 1-5 regional models per patient; Table 1). Histologically, broad similarity was observed between PDX models and corresponding patient tumor regions, although in a small number of models, variability was noted between the patient tumor and the corresponding PDX model, or during PDX passaging. PDXs were subjected to WES for comparison with matched patient tumor regions. Overall, our study demonstrates the feasibility of systematic multi-region PDX derivation and suggests that multiple spatial sampling of tumors could improve PDX take rates and generate PDXs that represent the intratumor diversity of heterogenous NSCLCs. Table 1. Engraftment rates of multiple spatial regions from non-small cell lung cancer tumors. Attempted NSCLC PDX B-Lymphoproliferations No Xenograft: Regions No Xenograft: Any Region LUAD 48 (21) 12 (7) 9 (7) 27 (10) LUSC 61 (17) 20 (11) 6 (5) 35 (4) Other 25 (6) 12 (4) 1 (1) 12 (1) TOTAL 134 (44) 44 (22) 16 (13) 74 (15) Citation Format: Robert E. Hynds, David R. Pearce, Ayse U. Akarca, Sophia Ward, Ariana Huebner, Oriol Pich, Gareth A. Wilson, Kate H. Gowers, Rebecca Towns, Assma Ben Aissa, Selvaraju Veeriah, Sergio A. Quezada, Mariam Jamal-Hanjani, Sam M. Janes, Nicholas McGranahan, David A. Moore, Teresa Marafioti, Charles Swanton. Multi-region patient-derived xenograft models from non-small cell lung cancer patients enrolled in lung TRACERx [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3096.

Malignant Pleural Mesothelioma (MPM) is typically diagnosed 20–50 years after exposure to asbestos and evolves along an unknown evolutionary trajectory. To elucidate this path, we conducted multi-regional exome sequencing of 90 tumour samples from 22 MPMs acquired at surgery. Here we show that exomic intratumour heterogeneity varies widely across the cohort. Phylogenetic tree topology ranges from linear to highly branched, reflecting a steep gradient of genomic instability. Using transfer learning, we detect repeated evolution, resolving 5 clusters that are prognostic, with temporally ordered clonal drivers. BAP1/−3p21 and FBXW7/-chr4 events are always early clonal. In contrast, NF2/−22q events, leading to Hippo pathway inactivation are predominantly late clonal, positively selected, and when subclonal, exhibit parallel evolution indicating an evolutionary constraint. Very late somatic alteration of NF2/22q occurred in one patient 12 years after surgery. Clonal architecture and evolutionary clusters dictate MPM inflammation and immune evasion. These results reveal potentially drugable evolutionary bottlenecking in MPM, and an impact of clonal architecture on shaping the immune landscape, with potential to dictate the clinical response to immune checkpoint inhibition., The impact of intratumour heterogeneity on immune surveillance and clinical outcomes has not been adequately explored in malignant pleural mesothelioma (MPM). Here the authors analyse the influence of evolution on the survival and immune landscape of MPM patients using multi-region sequencing data.

Background & Aims Colorectal cancer (CRC) shows variable response to immune checkpoint blockade, which can only partially be explained by high tumor mutational burden (TMB). We conducted an integrated study of the cancer tissue and associated tumor microenvironment (TME) from patients treated with pembrolizumab (KEYNOTE 177 clinical trial) or nivolumab to dissect the cellular and molecular determinants of response to anti- programmed cell death 1 (PD1) immunotherapy. Methods We selected multiple regions per tumor showing variable T-cell infiltration for a total of 738 regions from 29 patients, divided into discovery and validation cohorts. We performed multiregional whole-exome and RNA sequencing of the tumor cells and integrated these with T-cell receptor sequencing, high-dimensional imaging mass cytometry, detection of programmed death-ligand 1 (PDL1) interaction in situ, multiplexed immunofluorescence, and computational spatial analysis of the TME. Results In hypermutated CRCs, response to anti-PD1 immunotherapy was not associated with TMB but with high clonality of immunogenic mutations, clonally expanded T cells, low activation of Wnt signaling, deregulation of the interferon gamma pathway, and active immune escape mechanisms. Responsive hypermutated CRCs were also rich in cytotoxic and proliferating PD1+CD8 T cells interacting with PDL1+ antigen-presenting macrophages. Conclusions Our study clarified the limits of TMB as a predictor of response of CRC to anti-PD1 immunotherapy. It identified a population of antigen-presenting macrophages interacting with CD8 T cells that consistently segregate with response. We therefore concluded that anti-PD1 agents release the PD1-PDL1 interaction between CD8 T cells and macrophages to promote cytotoxic antitumor activity., Graphical abstract, Colorectal cancers responsive to anti-programmed cell death 1 immunotherapy show clonal immunogenic mutations, low Wnt activation, beta-2-microglobulin deregulation, and high infiltration of antigen presenting macrophages interacting with programmed cell death 1-positive cluster of differentiation 8 T cells.

The immune microenvironment influences tumour evolution and can be both prognostic and predict response to immunotherapy

Colorectal cancers (CRCs) show variable response to immune checkpoint blockade, which can only partially be explained by the variability of tumour mutational burden. To dissect the cellular and molecular determinants of response we performed a multi-omic screen of 721 cancer regions from patients treated with Pembrolizumab (KEYNOTE 177 clinical trial) or Nivolumab. Multi-regional whole exome, RNA and T-cell receptor sequencing show that, within hypermutated CRCs, response to both anti-PD1 agents is not positively associated with tumour mutational burden but with high clonality of immunogenic mutations, expanded T cells, low activation of the WNT pathway and active immune escape mechanisms. Coupling high-dimensional imaging mass cytometry with multiplexed immunofluorescence and computational spatial analysis, we observe that responsive hypermutated CRCs are rich in cytotoxic and proliferating PD1-expressing CD8 cells interacting with high-density clusters of PDL1-expressing antigen presenting macrophages. We propose that anti-PD1 agents release the PD1-PDL1 interaction between CD8 T cells and macrophages thus promoting cytotoxic anti-tumour activity.

Chromosomal instability in cancer consists of dynamic changes to the number and structure of chromosomes(1,2). The resulting diversity in somatic copy number alterations (SCNAs) may provide the variation necessary for tumour evolution(1,3,4). Here we use multi-sample phasing and SCNA analysis of 1,421 samples from 394 tumours across 22 tumour types to show that continuous chromosomal instability results in pervasive SCNA heterogeneity. Parallel evolutionary events, which cause disruption in the same genes (such asBCL9, MCL1,ARNT(also known asHIF1B),TERTandMYC) within separate subclones, were present in 37% of tumours. Most recurrent losses probably occurred before whole-genome doubling, that was found as a clonal event in 49% of tumours. However, loss of heterozygosity at the human leukocyte antigen (HLA) locus and loss of chromosome 8p to a single haploid copy recurred at substantial subclonal frequencies, even in tumours with whole-genome doubling, indicating ongoing karyotype remodelling. Focal amplifications that affected chromosomes 1q21 (which encompassesBCL9, MCL1andARNT), 5p15.33 (TERT), 11q13.3 (CCND1), 19q12 (CCNE1) and 8q24.1 (MYC) were frequently subclonal yet appeared to be clonal within single samples. Analysis of an independent series of 1,024 metastatic samples revealed that 13 focal SCNAs were enriched in metastatic samples, including gains in chromosome 8q24.1 (encompassingMYC) in clear cell renal cell carcinoma and chromosome 11q13.3 (encompassingCCND1) in HER2(+)breast cancer. Chromosomal instability may enable the continuous selection of SCNAs, which are established as ordered events that often occur in parallel, throughout tumour evolution.Chromosomal instability enables the continuous selection of somatic copy number alterations, which are established as ordered events that often occur in parallel, throughout tumour evolution and metastasis.

In the version of this article initially published, the list of members and affiliations for The TRACERx Consortium was provided as a Supplementary Note. The list should have been provided in the online version. Also, an incorrect version of Fig. 2b was published. The correct version is provided below. The errors have been corrected in the HTML and PDF versions of the article.

Pre-clinical non-small cell lung cancer (NSCLC) models are poorly representative of the considerable inter- and intra-tumor heterogeneity of the disease in patients. Primary cell-based in vitro models of NSCLC are therefore desirable for novel therapy development and personalized cancer medicine. Methods have been described to generate rapidly proliferating epithelial cell cultures from multiple human epithelia using 3T3-J2 feeder cell culture in the presence of Y-27632, a RHO-associated protein kinase (ROCK) inhibitor, in what are known as "conditional reprograming conditions" (CRC) or 3T3 + Y. In some cancer studies, variations of this methodology have allowed primary tumor cell expansion across a number of cancer types but other studies have demonstrated the preferential expansion of normal epithelial cells from tumors in such conditions. Here, we report our experience regarding the derivation of primary NSCLC cell cultures from 12 lung adenocarcinoma patients enrolled in the Tracking Cancer Evolution through Therapy (TRACERx) clinical study and discuss these in the context of improving the success rate for in vitro cultivation of cells from NSCLC tumors.

Malignant Pleural Mesothelioma (MPM) is typically diagnosed 20-50 years after exposure to asbestos and evolves along an unknown evolutionary trajectory. To elucidate this path, we conducted multi-regional exome sequencing of 90 tumour samples from 22 MPMs acquired at surgery. Here we show that exomic intratumour heterogeneity varies widely across the cohort. Phylogenetic tree topology ranges from linear to highly branched, reflecting a steep gradient of genomic instability. Using transfer learning, we detect repeated evolution, resolving 5 clusters that are prognostic, with temporally ordered clonal drivers. BAP1/-3p21 and FBXW7/-chr4 events are always early clonal. In contrast, NF2/-22q events, leading to Hippo pathway inactivation are predominantly late clonal, positively selected, and when subclonal, exhibit parallel evolution indicating an evolutionary constraint. Very late somatic alteration of NF2/22q occurred in one patient 12 years after surgery. Clonal architecture and evolutionary clusters dictate MPM inflammation and immune evasion. These results reveal potentially drugable evolutionary bottlenecking in MPM, and an impact of clonal architecture on shaping the immune landscape, with potential to dictate the clinical response to immune checkpoint inhibition.

A widespread approach to modern cancer therapy is to identify a single oncogenic driver gene and target its mutant-protein product (for example, EGFR-inhibitor treatment in EGFR-mutant lung cancers). However, genetically driven resistance to targeted therapy limits patient survival. Through genomic analysis of 1,122 EGFR-mutant lung cancer cell-free DNA samples and whole-exome analysis of seven longitudinally collected tumor samples from a patient with EGFR-mutant lung cancer, we identified critical co-occurring oncogenic events present in most advanced-stage EGFR-mutant lung cancers. We defined new pathways limiting EGFR-inhibitor response, including WNT/β-catenin alterations and cell-cycle-gene (CDK4 and CDK6) mutations. Tumor genomic complexity increases with EGFR-inhibitor treatment, and co-occurring alterations in CTNNB1 and PIK3CA exhibit nonredundant functions that cooperatively promote tumor metastasis or limit EGFR-inhibitor response. This study calls for revisiting the prevailing single-gene driver-oncogene view and links clinical outcomes to co-occurring genetic alterations in patients with advanced-stage EGFR-mutant lung cancer.

Background: \ud Among patients with non–small-cell lung cancer (NSCLC), data on intratumor heterogeneity and cancer genome evolution have been limited to small retrospective cohorts. We wanted to prospectively investigate intratumor heterogeneity in relation to clinical outcome and to determine the clonal nature of driver events and evolutionary processes in early-stage NSCLC.\ud \ud Methods: \ud In this prospective cohort study, we performed multiregion whole-exome sequencing on 100 early-stage NSCLC tumors that had been resected before systemic therapy. We sequenced and analyzed 327 tumor regions to define evolutionary histories, obtain a census of clonal and subclonal events, and assess the relationship between intratumor heterogeneity and recurrence-free survival.\ud \ud Results: \ud We observed widespread intratumor heterogeneity for both somatic copy-number alterations and mutations. Driver mutations in EGFR, MET, BRAF, and TP53 were almost always clonal. However, heterogeneous driver alterations that occurred later in evolution were found in more than 75% of the tumors and were common in PIK3CA and NF1 and in genes that are involved in chromatin modification and DNA damage response and repair. Genome doubling and ongoing dynamic chromosomal instability were associated with intratumor heterogeneity and resulted in parallel evolution of driver somatic copy-number alterations, including amplifications in CDK4, FOXA1, and BCL11A. Elevated copy-number heterogeneity was associated with an increased risk of recurrence or death (hazard ratio, 4.9; P=4.4×10−4), which remained significant in multivariate analysis.\ud \ud Conclusions: \ud Intratumor heterogeneity mediated through chromosome instability was associated with an increased risk of recurrence or death, a finding that supports the potential value of chromosome instability as a prognostic predictor. (Funded by Cancer Research UK and others; TRACERx ClinicalTrials.gov number, NCT01888601.)

Whole genome doubling (WGD) is a prevalent macro-evolutionary event in cancer, involving a doubling of the entire chromosome complement. However, despite its prevalence and clinical prognostic relevance, the evolutionary selection pressures for WGD have not been investigated. Here, we explored whether WGD may act to mitigate the irreversible, inexorable ratchet-like, accumulation of deleterious mutations in essential genes. Utilizing 1050 tumor regions from 816 non-small cell lung cancers (NSCLC), we temporally dissect mutations to determine their temporal acquisition in relation to WGD. We find evidence for strong negative selection against homozygous loss of essential cancer genes prior to WGD. However, mutations in essential genes occurring after duplication were not subject to significant negative selection, consistent with WGD providing a buffering effect, decreasing the likelihood of homozygous loss. Finally, we demonstrate that loss of heterozygosity and temporal dissection of mutations can be exploited to identify signals of positive selection in lung, breast, colorectal cancer and other cancer types, enabling the elucidation of novel tumour suppressor genes and a deeper characterization of known cancer genes.

Somatic mutations together with immunoediting drive extensive heterogeneity within non-small-cell lung cancer (NSCLC). Herein we examine heterogeneity of the T cell antigen receptor (TCR) repertoire. The number of TCR sequences selectively expanded in tumors varies within and between tumors and correlates with the number of nonsynonymous mutations. Expanded TCRs can be subdivided into TCRs found in all tumor regions (ubiquitous) and those present in a subset of regions (regional). The number of ubiquitous and regional TCRs correlates with the number of ubiquitous and regional nonsynonymous mutations, respectively. Expanded TCRs form part of clusters of TCRs of similar sequence, suggestive of a spatially constrained antigen-driven process. CD8+ tumor-infiltrating lymphocytes harboring ubiquitous TCRs display a dysfunctional tissue-resident phenotype. Ubiquitous TCRs are preferentially detected in the blood at the time of tumor resection as compared to routine follow-up. These findings highlight a noninvasive method to identify and track relevant tumor-reactive TCRs for use in adoptive T cell immunotherapy.

An aim of molecular biomarkers is to stratify patients with cancer into disease subtypes predictive of outcome, improving diagnostic precision beyond clinical descriptors such as tumor stage1. Transcriptomic intratumor heterogeneity (RNA-ITH) has been shown to confound existing expression-based biomarkers across multiple cancer types2–6. Here, we analyze multi-region whole-exome and RNA sequencing data for 156 tumor regions from 48 patients enrolled in the TRACERx study to explore and control for RNA-ITH in non-small cell lung cancer. We find that chromosomal instability is a major driver of RNA-ITH, and existing prognostic gene expression signatures are vulnerable to tumor sampling bias. To address this, we identify genes expressed homogeneously within individual tumors that encode expression modules of cancer cell proliferation and are often driven by DNA copy-number gains selected early in tumor evolution. Clonal transcriptomic biomarkers overcome tumor sampling bias, associate with survival independent of clinicopathological risk factors, and may provide a general strategy to refine biomarker design across cancer types. TRACERx Lung: Intratumoral transcriptional heterogeneity, which often hinders the development of clinically useful RNA-expression-biased biomarkers for cancer, can now be overcome with an approach for the identification of clonal expression biomarkers.

Whole-genome doubling (WGD) is a prevalent event in cancer, involving a doubling of the entire chromosome complement. However, despite its prevalence and prognostic relevance, the evolutionary selection pressures for WGD in cancer have not been investigated. Here, we combine evolutionary simulations with an analysis of cancer sequencing data to explore WGD during cancer evolution. Simulations suggest that WGD can be selected to mitigate the irreversible, ratchet-like, accumulation of deleterious somatic alterations, provided that they occur at a sufficiently high rate. Consistent with this, we observe an enrichment for WGD in tumor types with extensive loss of heterozygosity, including lung squamous cell carcinoma and triple-negative breast cancers, and we find evidence for negative selection against homozygous loss of essential genes before, but not after, WGD. Finally, we demonstrate that loss of heterozygosity and temporal dissection of mutations can be exploited to identify novel tumor suppressor genes and to obtain a deeper characterization of known cancer genes.

The aim of this pilot study was to assess whether both ubiquitous and heterogeneous somatic mutations could be detected in cell-free DNA (cfDNA) from patients with early-stage non-small-cell lung cancer (NSCLC).Three stage I and one stage II primary NSCLC tumors were subjected to multiregion whole-exome sequencing (WES) and validated with AmpliSeq. A subset of ubiquitous and heterogeneous single-nucleotide variants (SNVs) were chosen. Multiplexed PCR using custom-designed primers, coupled with next-generation sequencing (mPCR-NGS), was used to detect these SNVs in both tumor DNA and cfDNA isolated from plasma obtained before surgical resection of the tumors. The limit of detection for each assay was determined using cfDNA from 48 presumed-normal healthy volunteers.Tumor DNA and plasma-derived cfDNA was successfully amplified and sequenced for 37/50 (74%) SNVs using the mPCR-NGS method. Twenty-five (68%) were ubiquitous and 12 (32%) were heterogeneous SNVs. Variant detection by mPCR-NGS and WES-AmpliSeq in tumor tissue was well correlated (R(2) = 0.8722, P0.0001). Sixteen (43%) out of 37 SNVs were detected in cfDNA. Twelve of these were ubiquitous SNVs with a variant allele frequency (VAF) range of 0.15-23.25%, and four of these were heterogeneous SNVs with a VAF range of 0.28-1.71%. There was a statistically significant linear relationship between the VAFs for tumor and cfDNA (R(2) = 0.5144; P = 0.0018). For all four patients, at least two variants were detected in plasma. The estimated number of copies of variant DNA present in each sample ranged from 5 to 524. The average number of variant copies required for detection (VCRD) was 3.16 (range: 0.2-7.6 copies).The mPCR-NGS method revealed intratumor heterogeneity in early-stage NSCLC tumors, and was able to detect both ubiquitous and heterogeneous SNVs in cfDNA. Further validation of mPCR-NGS in cfDNA is required to define its potential use in clinical practice.

Background: Clonal neoantigens are formed early in cancer evolution and have been identified as a subset of patient specific mutations that are associated with improved clinical benefit and represent great promise as targets for the next generation of T cell therapies. Developing T cell therapies that target multiple clonal neoantigens represents a unique personalized approach to treating solid cancer, as they are present on all cancer cells, minimizing the risk of tumour escape, and absent from healthy tissue, potentially eliminating off-target toxicities. Access to sequencing data from over 600 NSCLC patients enrolled in the UK TRACERx study has enabled the development of the Achilles PELEUSTM bioinformatic platform. By opening an ethically approved tissue collection study NCT03517917, enabling access to matched tumour and blood samples from patients with selected cancers, our clonal neoantigen reactive T cell (cNeT) manufacturing process and supply chain has been validated for use in clinical trials. Methods: Matched tumor and blood samples were procured at the time of routine surgery from ten patients (eight with newly diagnosed stage I-III NSCLC and two with metastatic melanoma) for at-scale GMP runs. Briefly, TIL were isolated from tumor fragments and immature dendritic cells (DCs) generated from whole blood, prior to cryopreservation as intermediate products. Patient-specific clonal neoantigens were predicted using our proprietary PELEUSTM bioinformatic platform, enabling the manufacture of synthetic peptide masterpools to be used for the enrichment of cNeT in the VELOSTM manufacturing process. Co-culture of pre-expanded TIL and patient DCs loaded with clonal neoantigen peptides drives the selective expansion of cNeT, eliminating the requirement for high non-physiological levels of IL-2. Results: Here we present the successful scaled GMP production of cNeT from both primary and metastatic tumors using the VELOSTM manufacturing process in ten patients. All final products met QC release criteria and were composed of both CD4+ and CD8+ T cells. Extensive characterization of T cell responses showed cNeT exhibited functional responses determined by cytokine secretion following re-challenge, and specificity in response to clonal neoantigen peptides. Peptide deconvolution of masterpools identified multiple single T cell clone reactivities to clonal neoantigens in the final product. Conclusions: The VELOSTM process incorporating the PELEUSTM bioinformatic platform for prediction of clonal neoantigens is a novel platform for generating personalized T cell products directed at multiple cancer clonal neoantigen targets and has the potential to be utilized across a variety of solid tumors. This study demonstrates the feasibility of generating cNeT for the treatment of both advanced NSCLC and recurrent or metastatic melanoma and supported the successful regulatory approval in two first-in-human studies (NCT04032847 and NCT03997474) which opened in the UK in 2019. Citation Format: Henrieta Fraser, Rebecca Pike, Sarah Thirkell, Asiya Arshad, Sam Jide-Banwo, Hollie Bartley, Evi Rologi, Michal Pruchniak, Shreenal Patel, Jennine Mootien, Jane Robertson, Andrew Craig, Max Salm, Katy Newton, Luke Goodsell, Fong Chan, Gareth Wilson, Stephen Frenk, Iraj Ali, Karl Peggs, Mark W. Lowdell, Lyra Del Rosio, Andrew Hayes, Samra Turajlic, Farah Islam, David Lawrence, Mariam Jamal-Hanjani, Martin D. Forster, Edward Samuel. The development of a personalized autologous clonal neoantigen T cell therapy for the treatment of solid cancer using the VELOSTM manufacturing platform generates highly potent and reactive CD8+ and CD4+ T cells for clinical use [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 CT054.

Introduction: Kirsten rat sarcoma viral oncogene (KRAS) is the most frequently mutated oncogene in non-small cell lung cancer (NSCLC), occurring in approximately 30% of cases. Recent work suggests KRAS -mutant (KRASm) NSCLC is a microcosm for diverse immune checkpoint inhibitor responses, partly dictated by its co-mutation with TP53 (“KP” group=~1/3 cases, “immune hot”), STK11 (“KL” group=~1/3 cases, “immune cold”) or CDKN2A (“KC” group=~1/3 cases). Here we identify and describe genomic and clinical associations of a further subset of KRASm NSCLC defined by “triple WT” status for common KRASm co-mutations. Method: Sequencing results from 364 early-stage NSCLC cases from the Cancer Research UK TRACERx program (whole-exome sequencing) and the Genomics England 100,000 genome program (whole-genome sequencing) were analyzed for KRASm, associated co-mutations in TP53, STK11 and CDKN2A, copy number changes in the RAS-RAF-MEK-ERK axis, tumor mutational burden (TMB) and mutational signatures. Clinical demographics and factors including tumor size, nodal status and stage were ascertained and assessed for statistical associations with sequencing data using the Mann-Whitney and Fisher’s exact tests. Results: Overall, 143/364 lung cancer cases (39%) were KRASm with 65/143 (45%) tumors identified as “KP,” 26/143 (18%) as “KL,” and 3/143 (2%) as “KC.” There were 49/143 KRASm cases (34%) with no co-mutation in TP53, STK11 or CDKN2A, defined as “triple wild-type” (triple WT). Relative to the KP, KL and KC genotypes, there was a positive association of the KRAS G12D mutation with triple WT status: 10/49 cases, 20%; KP/KL/KC: 6/94 cases, 6%; p=0.022). In the 100,000-genome cohort, TMB was similar for the triple WT and KL groups but significantly lower than that observed for KP (KP: median 10.55 mut/Mb, 95% CI 8.8-15.33; triple WT: median 6.96, 95% CI 4.87-12.53; p=0.036). Despite this lower median TMB, smoking-associated mutational signature 4 was common in triple WT tumors (triple WT: 13/14 pts, 93%; overall 76/114 pts, 67%). In the triple WT group overall, there was a reduction of >50% in cancers with copy number changes of NF1 and NRAS. There was an inverse association between pathologic stage III tumors and KRASm triple WT genotype (p=0.0014). Conclusion: There are a significant proportion of KRASm NSCLC patients whose tumors are triple WT for TP53, STK11 and CDKN2A. Despite their high frequency of smoking-associated mutational signatures, these tumors are characterized by low TMB and are more common in early-stage disease. They also associate more commonly with KRAS G12D. Our observations suggest a discrete KRASm subset that may have implications for stratification in trials of immune checkpoint inhibitors and/or targeted therapeutics of KRASm tumors. Citation Format: Colin R. Lindsay, Pantelis Nicola, Mariam Jamal-Hanjani, Andrew Wallace, Gareth Wilson, George Burghel, Helene Schlecht, Katie Baker, Eleanour Baker, Lynsey Priest, Jane Rogan, Sharzad Moghadam, Mathew Carter, Caroline Dive, Robert G. Bristow, Charles Swanton, William Newman, Fiona Blackhall. “Triple wild-type” co-mutational profile in early-stage KRAS-mutant lung cancer [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr B49.

Cancer is an evolutionary process. Recent advances in sequencing technologies have allowed us to investigate intratumor heterogeneity at the single nucleotide level. Here, we describe computational methods that use sequencing data to identify genetically distinct tumor subclones and reconstruct tumor evolutionary histories.

Cancer is an evolutionary process. Recent advances in sequencing technologies have allowed us to investigate intratumor heterogeneity at the single nucleotide level. Here, we describe computational methods that use sequencing data to identify genetically distinct tumor subclones and reconstruct tumor evolutionary histories.

The evolutionary features of clear-cell renal cell carcinoma (ccRCC) have not been systematically studied to date. We analyzed 1,206 primary tumor regions from 101 patients recruited into the multi-center prospective study, TRACERx Renal. We observe up to 30 driver events per tumor and show that subclonal diversification is associated with known prognostic parameters. By resolving the patterns of driver event ordering, co-occurrence, and mutual exclusivity at clone level, we show the deterministic nature of clonal evolution. ccRCC can be grouped into seven evolutionary subtypes, ranging from tumors characterized by early fixation of multiple mutational and copy number drivers and rapid metastases to highly branched tumors with > 10 subclonal drivers and extensive parallel evolution associated with attenuated progression. We identify genetic diversity and chromosomal complexity as determinants of patient outcome. Our insights reconcile the variable clinical behavior of ccRCC and suggest evolutionary potential as a biomarker for both intervention and surveillance. We thank Aida Murra, Naheed Shaikh, Justine Korteweg, Jeremy Tai, Eleanor Carlyle, Leonora Conneely, KimEdmonds, Karla Lingard, Karen O'Meara, Helen Breeze, Sarah Sarker, Lesley Cooper, Linda Shephard, Susie Slater, and Catherine Rogers for study support. We thank the patients and their families. S.T. and H.X. are funded by Cancer Research UK (CRUK) (C50947/A18176). S.T., T.C., J.L., and M.G. are funded by the National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) at the Royal Marsden Hospital and Institute of Cancer Research (A109). J.I.L. is funded by the Ministerio de Economia y Competitividad (MINECO, SAF2016-79847-R). M.S., A.S., J. Lynch, R.F., L.A., and L.S. are funded by the Royal Marsden Cancer Charity. K.L. is funded by UK Medical Research Council (MR/P014712/1). T.B.K.W. is funded by the European Union Seventh Framework Programme (FP7-People-2013-ITN). M.J.-H. is funded by the NIHR. N.M.L. is a Winton Group Leader in recognition of the Winton Charitable Foundation's support towards the establishment of The Francis Crick Institute. N.M.L. is additionally funded by a Wellcome Trust Joint Investigator Award (103760/Z/14/Z) and the MRC eMedLab Medical Bioinformatics Infrastructure Award (MR/L016311/1). M.K. is funded by the Danish Cancer Society grant (R90-A6213). P.C. is funded by the Wellcome Trust (WT088340MA). N.M. receives funding from CRUK, Rosetrees, and the NIHR BRC at University College London Hospitals. C.S. is a Royal Society Napier Research Professor. C.S. is funded by Cancer Research UK (TRACERx and CRUK Cancer Immunotherapy Catalyst Network), the CRUK Lung Cancer Centre of Excellence, Stand Up 2 Cancer (SU2C), the Rosetrees and Stoneygate Trusts, NovoNordisk Foundation (THESEUS), Marie Curie Network PloidyNet, the NIHR BRC at University College London Hospitals, and the CRUK University College London Experimental Cancer Medicine Centre. C.S., O.P., D.R., I.C., and Z.S. are funded by NovoNordisk Foundation (16584). O.P., D.R., and I.C. are funded by the National Research, Development and Innovation Office of Hungary (NVKP_16-1-20160004). This work was supported by CRUK (Clinical Scientist Fellowship to S.T., C50947/A18176), The Francis Crick Institute, which receives its core funding from Cancer Reseach UK (FC010110), the UK Medical Research Council (FC010110), the Wellcome Trust (FC010110), and NIHR BRC at the Royal Marsden Hospital and Institute of Cancer Research (A109). High-performance computing was supported by eMedLab. The results published here are in whole or part based upon data generated by the TCGA Research Network: http://cancergenome.nih.gov/.

Immune evasion is a hallmark of cancer. Losing the ability to present neoantigens through human leukocyte antigen (HLA) loss may facilitate immune evasion. However, the polymorphic nature of the locus has precluded accurate HLA copy-number analysis. Here, we present loss of heterozygosity in human leukocyte antigen (LOHHLA), a computational tool to determine HLA allele-specific copy number from sequencing data. Using LOHHLA, we find that HLA LOH occurs in 40% of non-small-cell lung cancers (NSCLCs) and is associated with a high subclonal neoantigen burden, APOBEC-mediated mutagenesis, upregulation of cytolytic activity, and PD-L1 positivity. The focal nature of HLA LOH alterations, their subclonal frequencies, enrichment in metastatic sites, and occurrence as parallel events suggests that HLA LOH is an immune escape mechanism that is subject to strong microenvironmental selection pressures later in tumor evolution. Characterizing HLA LOH with LOHHLA refines neoantigen prediction and may have implications for our understanding of resistance mechanisms and immunotherapeutic approaches targeting neoantigens. VIDEO ABSTRACT.

The current understanding of tumorigenesis is largely centered on a monogenic driver oncogene model. This paradigm is incompatible with the prevailing clinical experience in most solid malignancies: monotherapy with a drug directed against an individual oncogenic driver typically results in incomplete clinical responses and eventual tumor progression1-7. By profiling the somatic genetic alterations present in over 2,000 cases of lung cancer, the leading cause of cancer mortality worldwide8,9, we show that combinations of functional genetic alterations, i.e. genetic collectives dominate the landscape of advanced-stage disease. We highlight this polygenic landscape and evolution of advanced-stage non-small cell lung cancer (NSCLC) through the spatial-temporal genomic profiling of 7 distinct tumor biopsy specimens and 6 plasma specimens obtained from an EGFR-mutant NSCLC patient at (1) initial diagnosis of early-stage disease, (2) metastatic progression, (3) sequential treatment and resistance to 2 EGFR inhibitors, (4) death. The comprehensive genomic analysis of this case, coupled with circulating free (cf) tumor DNA profiling of additional advanced-stage EGFR-mutant NSCLC clinical cohorts with associated treatment responses uncovered features of evolutionary selection for multiple concurrent gene alterations: including the presence of EGFR inhibitor-sensitive (EGFRL858R;EGFRexon19del) or inhibitor-resistant (EGFRT790M;EGFRC797S) forms of oncogenic EGFR along with cell cycle gene alterations (e.g. in CDK4/6, CCNE1, RB1) and activating alterations in WNT/β-catenin and PI3K pathway genes, which our data suggest can cooperatively impart non-redundant functions to limit EGFR targeted therapy response and/or promote tumor progression. Moreover, evidence of an unanticipated parallel evolution of both EGFRT790M and two distinct forms of oncogenic PIK3CA was observed. Our study provides a large-scale clinical and genetic dataset of advanced-stage EGFR-mutant NSCLC, a rationale for specific polytherapy strategies such as EGFR and CDK4/6 inhibitor co-treatment to potentially enhance clinical outcomes, and prompts a re-evaluation of the prevailing paradigm of monogenic-based molecular stratification for targeted therapy. Instead, our findings highlight an alternative model of genetic collectives that operate through epistasis to drive lung cancer progression and therapy resistance.

Background Intratumoural heterogeneity (ITH) is well recognised in prostate cancer (PC), but its role in high-risk disease is uncertain. A prospective, single-arm, translational study using targeted multiregion prostate biopsies was carried out to study genomic and T-cell ITH in clinically high-risk PC aiming to identify drivers and potential therapeutic strategies. Patients and methods Forty-nine men with elevated prostate-specific antigen and multiparametric-magnetic resonance imaging detected PC underwent image-guided multiregion transperineal biopsy. Seventy-nine tumour regions from 25 patients with PC underwent sequencing, analysis of mutations, copy number and neoepitopes combined with tumour infiltrating T-cell subset quantification. Results We demonstrated extensive somatic nucleotide variation and somatic copy number alteration heterogeneity in high-risk PC. Overall, the mutational burden was low (0.93/Megabase), but two patients had hypermutation, with loss of mismatch repair (MMR) proteins, MSH2 and MSH6. Somatic copy number alteration burden was higher in patients with metastatic hormone-naive PC (mHNPC) than in those with high-risk localised PC (hrlPC), independent of Gleason grade. Mutations were rarely ubiquitous and mutational frequencies were similar for mHNPC and hrlPC patients. Enrichment of focal 3q26.2 and 3q21.3, regions containing putative metastasis drivers, was seen in mHNPC patients. We found evidence of parallel evolution with three separate clones containing activating mutations of β-catenin in a single patient. We demonstrated extensive intratumoural and intertumoural T-cell heterogeneity and high inflammatory infiltrate in the MMR-deficient (MMRD) patients and the patient with parallel evolution of β-catenin. Analysis of all patients with activating Wnt/β-catenin mutations demonstrated a low CD8+/FOXP3+ ratio, a potential surrogate marker of immune evasion. Conclusions The PROGENY (PROstate cancer GENomic heterogeneitY) study provides a diagnostic platform suitable for studying tumour ITH. Genetic aberrations in clinically high-risk PC are associated with altered patterns of immune infiltrate in tumours. Activating mutations of Wnt/β-catenin signalling pathway or MMRD could be considered as potential biomarkers for immunomodulation therapies. Clinical Trials.gov Identifier NCT02022371

Stem cells have been found in most tissues/organs. These somatic stem cells produce replacements for lost and damaged cells, and it is not completely understood how this regenerative capacity becomes diminished during aging. To study the possible involvement of epigenetic changes in somatic stem cell aging, we used murine hematopoiesis as a model system. Hematopoietic stem cells (HSCs) were enriched for via Hoechst exclusion activity (SP-HSC) from young, medium-aged and old mice and subjected to comprehensive, global methylome (MeDIP-seq) analysis. With age, we observed a global loss of DNA methylation of approximately 5%, but an increase in methylation at some CpG islands. Just over 100 significant (FDR < 0.2) aging-specific differentially methylated regions (aDMRs) were identified, which are surprisingly few considering the profound age-based changes that occur in HSC biology. Interestingly, the polycomb repressive complex -2 (PCRC2) target genes Kiss1r, Nav2 and Hsf4 were hypermethylated with age. The promoter for the Sdpr gene was determined to be progressively hypomethylated with age. This occurred concurrently with an increase in gene expression with age. To explore this relationship further, we cultured isolated SP-HSC in the presence of 5-aza-deoxycytdine and demonstrated a negative correlation between Sdpr promoter methylation and gene expression. We report that DNA methylation patterns are well preserved during hematopoietic stem cell aging, confirm that PCRC2 targets are increasingly methylated with age, and suggest that SDPR expression changes with age in HSCs may be regulated via age-based alterations in DNA methylation.

At the point of cancer diagnosis, molecular biomarkers aim to stratify patients into precise disease subtypes predictive of outcome independent of standard clinical parameters such as tumour stage. Although prognostic gene expression signatures have been derived for many cancer types, seldom have they been shown to improve therapeutic decision making, limiting their clinical use. While intra-tumour transcriptomic heterogeneity (RNA-ITH) has been shown to bias existing biomarkers, efforts to control for this biological parameter have not been considered in biomarker development. Here, we analyse multi-region RNA-seq and whole-exome data for 156 tumour regions from 48 TRACERx patients to explore RNA-ITH in NSCLC. We show that chromosomal instability is a major driver of RNA-ITH, through the generation of heterogeneous copy number events within tumours, and that existing prognostic gene expression signatures are vulnerable to sampling bias. To address this issue, we develop the Outcome Risk Associated Clonal Lung Expression (ORACLE) assay, comprised of genes expressed homogeneously within individual tumours but heterogeneously between patients. These genes are enriched in modules associated with cell proliferation, such as mitosis and nucleosome assembly, that are often selected for through copy number gain events occurring early in tumour evolution. Our approach to identify “clonal” transcriptomic biomarkers in NSCLC overcomes tumour sampling bias, improves survival risk forecasting over current clinicopathological risk factors, and may be generalised to other cancer types, whilst revealing the early evolutionary selection of high risk DNA copy number events driving poor clinical outcome. Citation Format: Dhruva Biswas, Nicolai J. Birkbak, Rachel Rosenthal, Crispin T. Hiley, Emilia L. Lim, Krisztian Papp, Marcin Krzystanek, Dijana Djureinovic, Yin Wu, David A. Moore, Marcin Skrypski, Christopher Abbosh, Maise Al Bakir, Thomas B. Watkins, Selvaraju Veeriah, Gareth A. Wilson, Mariam Jamal-Hanjani, Arul M. Chinnaiyan, Patrick Micke, Jiri Bartek, Istvan Csabai, Zoltan Szallasi, Javier Herrero, Nicholas McGranahan, Charles Swanton. A clonal expression biomarker improves prognostic accuracy: TRACERx lung [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2678.

2590 Background: CD4 T helper cells are key orchestrators of immunity in states of persistent antigen exposure. In chronic viral infection, loss of immune control is associated with CD4 differentiation skewing (CD4ds) resulting from decline of early progenitors and gain in abundance of exhausted and terminally differentiated subsets. Here, we set out to identify whether a similar process occurs within the tumour microenvironment, contributing to immune dysfunction. Methods: Multiregional samples of tumour and non-tumour lung tissue from patients with untreated, surgically resected non-small cell lung cancer (NSCLC) within the first 100 recruited to the prospective lung TRACERx study were analysed by high dimensional flow cytometry of tumour infiltrating lymphocytes (TILs) and paired bulk tumour exome and RNA sequencing. We additionally reanalysed publically available single T cell and bulk tumour RNA sequencing from patients with NSCLC. Results: Unsupervised clustering and dimension reduction revealed a heterogenous landscape of CD4 TILs, with evidence of CD4ds in association with tumour mutational burden. Loss of PD1-CCR7+ T central memory enriched early differentiated cells was accompanied by gain in abundance of PD1+ populations with exhausted (CD57-ICOShiCTLA4hi) and terminally differentiated effector (CD57+Eomes+) phenotypes. Further characterisation of these populations by single cell RNA sequencing revealed differential expression of key genes involved in transcriptional regulation, co-inhibition and co-stimulatory pathways. A validated gene signature of CD4ds was associated with worse outcomes in TRACERx and TCGA cohorts. Conclusions: Our findings reveal remodelling of the CD4 differentiation landscape in association with tumour genomic characteristics, underscoring how mutational burden in the context of chronic stimulation may lead to loss of immune fitness and elucidating key regulatory pathways in potentially clinically relevant CD4 subsets.

One in six cancers worldwide is caused by infection and human papillomavirus (HPV) is one of the main culprits. To better understand the dynamics of HPV integration and its effect on both the viral and host methylomes, we conducted whole-genome DNA methylation analysis using MeDIP-seq of HPV+ and HPV- head and neck squamous cell carcinoma (HNSCC). We determined the viral subtype to be HPV-16 in all cases and show that HPV-16 integrates into the host genome at multiple random sites and that this process predominantly involves the transcriptional repressor gene (E2) in the viral genome. Comparative analysis identified 453 (FDR ≤ 0.01) differentially methylated regions (DMRs) in the HPV+ host methylome. Bioinformatics characterization of these DMRs confirmed the previously reported cadherin genes to be affected but also revealed new targets for HPV-mediated methylation changes at regions not covered by array-based platforms, including the recently identified super-enhancers.

The combinatorial number of possible methylomes in biological time and space is astronomical. Consequently, the computational analysis of methylomes needs to cater for a variety of data, throughput and resolution. Here, we review recent advances in 2nd generation sequencing (2GS) with a focus on the different methods used for the analysis of MeDIP-seq data. The challenges and opportunities presented by the integration of methylation data with other genomic data types are discussed as is the potential impact of emerging 3rd generation sequencing (3GS) based technologies on methylation analysis.

Regulatory change has long been hypothesized to drive the delineation of the human phenotype from other closely related primates. Here we provide evidence that CpG dinucleotides play a special role in this process. CpGs enable epigenome variability via DNA methylation, and this epigenetic mark functions as a regulatory mechanism. Therefore, species-specific CpGs may influence species-specific regulation. We report non-polymorphic species-specific CpG dinucleotides (termed "CpG beacons") as a distinct genomic feature associated with CpG island (CGI) evolution, human traits and disease. Using an inter-primate comparison, we identified 21 extreme CpG beacon clusters (≥ 20/kb peaks, empirical p < 1.0 × 10(-3)) in humans, which include associations with four monogenic developmental and neurological disease related genes (Benjamini-Hochberg corrected p = 6.03 × 10(-3)). We also demonstrate that beacon-mediated CpG density gain in CGIs correlates with reduced methylation in these species in orthologous CGIs over time, via human, chimpanzee and macaque MeDIP-seq. Therefore mapping into both the genomic and epigenomic space the identified CpG beacon clusters define points of intersection where a substantial two-way interaction between genetic sequence and epigenetic state has occurred. Taken together, our data support a model for CpG beacons to contribute to CGI evolution from genesis to tissue-specific to constitutively active CGIs. peerReviewed

The etiology of inflammatory bowel diseases is only partially explained by the current genetic risk map. It is hypothesized that environmental factors modulate the epigenetic landscape and thus contribute to disease susceptibility, manifestation, and progression. To test this, we analyzed DNA methylation (DNAm), a fundamental mechanism of epigenetic long-term modulation of gene expression. We report a three-layer epigenome-wide association study (EWAS) using intestinal biopsies from 10 monozygotic twin pairs (n = 20 individuals) discordant for manifestation of ulcerative colitis (UC). Genome-wide expression scans were generated using Affymetrix UG 133 Plus 2.0 arrays (layer 1). Genome-wide DNAm scans were carried out using Illumina 27k Infinium Bead Arrays to identify methylation variable positions (MVPs, layer 2), and MeDIP-chip on Nimblegen custom 385k Tiling Arrays to identify differentially methylated regions (DMRs, layer 3). Identified MVPs and DMRs were validated in two independent patient populations by quantitative real-time PCR and bisulfite-pyrosequencing (n = 185). The EWAS identified 61 disease-associated loci harboring differential DNAm in cis of a differentially expressed transcript. All constitute novel candidate risk loci for UC not previously identified by GWAS. Among them are several that have been functionally implicated in inflammatory processes, e.g., complement factor CFI, the serine protease inhibitor SPINK4, and the adhesion molecule THY1 (also known as CD90). Our study design excludes nondisease inflammation as a cause of the identified changes in DNAm. This study represents the first replicated EWAS of UC integrated with transcriptional signatures in the affected tissue and demonstrates the power of EWAS to uncover unexplained disease risk and molecular events of disease manifestation.

DNA methylation is an epigenetic mark that has a crucial role in many biological processes. To understand the functional consequences of DNA methylation on phenotypic plasticity, a genome-wide analysis should be embraced. This in turn requires a technique that balances accuracy, genome coverage, resolution and cost, yet is low in DNA input in order to minimize the drain on precious samples. Methylated DNA immunoprecipitation-sequencing (MeDIP-seq) fulfils these criteria, combining MeDIP with massively parallel DNA sequencing. Here we report an improved protocol using 100-fold less genomic DNA than that commonly used. We show comparable results for specificity (>97%) and enrichment (>100-fold) over a wide range of DNA concentrations (5,000-50 ng) and demonstrate the utility of the protocol for the generation of methylomes from rare bone marrow cells using 160-300 ng of starting DNA. The protocol described here, i.e., DNA extraction to generation of MeDIP-seq library, can be completed within 3-5 d.

As tumors grow, they acquire mutations, some of which create neoantigens that influence the response of patients to immune checkpoint inhibitors. We explored the impact of neoantigen intratumor heterogeneity (ITH) on antitumor immunity. Through integrated analysis of ITH and neoantigen burden, we demonstrate a relationship between clonal neoantigen burden and overall survival in primary lung adenocarcinomas. CD8(+)tumor-infiltrating lymphocytes reactive to clonal neoantigens were identified in early-stage non-small cell lung cancer and expressed high levels of PD-1. Sensitivity to PD-1 and CTLA-4 blockade in patients with advanced NSCLC and melanoma was enhanced in tumors enriched for clonal neoantigens. T cells recognizing clonal neoantigens were detectable in patients with durable clinical benefit. Cytotoxic chemotherapy-induced subclonal neoantigens, contributing to an increased mutational load, were enriched in certain poor responders. These data suggest that neoantigen heterogeneity may influence immune surveillance and support therapeutic developments targeting clonal neoantigens.

In order to avoid immune predation, particularly in response to immunotherapy, tumors must acquire mechanisms to evade immune detection or withstand its activity. Disruption of human leukocyte antigen (HLA), which may lead to reduced neoantigen presentation, has been proposed as an immune escape strategy in many cancers, including lung cancer. A high proportion of cancer types have been found to downregulate HLA expression, potentially leading to the evasion of T cell-mediated destruction (Hicklin, 1999; Garrido, 2017) with reduced HLA expression associating with decreased overall survival and tumor progression (Mehta, 2008). Another irreversible means of HLA disruption is via loss of heterozygosity (LOH) at the HLA locus (Koopman, 2000). However, to date, the diversity of the HLA locus has impeded copy number analysis and determination of HLA loss. To investigate the prevalence, timing, and importance of HLA disruption, we developed LOHHLA (Loss Of Heterozygosity in Human Leukocyte Antigen), a computational tool to determine HLA allele-specific copy number from sequencing data. Supporting the notion that loss of antigen presentation may play an important role in immune evasion during tumor evolution, HLA LOH was identified in 40% of the NSCLC samples analyzed, frequently as a late event in tumor evolution and associated with a high subclonal neoantigen burden, increase in immune infiltration, and PD-L1 positivity. Characterizing HLA haplotype specific copy number with LOHHLA refines neoantigen prediction and may have implications for immunotherapeutic approaches targeting neoantigens. Citation Format: Nicholas McGranahan, Rachel Rosenthal, Crispin T. Hiley, Andrew J. Rowan, Thomas B.K. Watkins, Gareth A. Wilson, Nicolai J. Birkbak, Selvaraju Veeriah, Peter Van Loo, Javier Herrero, Charles Swanton. Allele-specific HLA loss and immune escape in lung cancer evolution [abstract]. In: Proceedings of the Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; Jan 8-11, 2018; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(17_Suppl):Abstract nr IA23.

Introduction: For early stage NSCLC, surgery with curative intent is the most common therapeutic option; however, tumour recurrence occurs in approximately 50% of cases and most commonly at distant sites. Analysis of CTCs represents a potential means of tracking cancer cells from the primary tumour and has the potential to provide insights into the metastatic process and mechanisms of resistance to therapy linking cell phenotype and genotype. Within the TRACERx study, we are carrying out whole genome analysis of single CTCs obtained from NSCLC patients undergoing surgery in order to examine the relationship between CTCs, the primary tumour and metastatic relapse. Methods: Blood from 163 patients was collected at surgery from the tumour draining pulmonary vein and from peripheral vein in longitudinal samples. CTCs were enriched based on their EpCAM expression using CellSearch® and then enumerated according to their positivity for epithelial markers (Cytokeratins) and lack of detectable blood markers (CD45). Samples containing at least five CellSearch® CTCs (CS-CTCs) were processed through DEPArray™ for single cell isolation followed by whole genome amplification (WGA) using the Ampli1™ WGA kit. Genome wide copy number alterations (CNA) were detected through low-depth whole genome sequencing (WGS) and mutational analysis of individual CTCs was carried out using whole exome sequencing (WES). CTC genomic profiles were compared to the corresponding spatially separated tumour sections obtained at surgery. Results: In a pilot study of 30 patients undergoing tumour resection, the presence of pulmonary vein CS-CTCs has been linked to poor clinical outcome (Crosbie et al, J Thorac Oncol, 2016). Here we extended the evaluation of pulmonary vein CS-CTCs to a further 122 patients and confirmed the initial observation that the presence of pulmonary vein CS-CTCs is a poor prognostic indicator. CNA analysis of 100 single CTCs from the first 12 patients revealed heterogeneous patterns between patients and within individual patients. Three types of pulmonary CS-CTC candidates were observed: Type 1, which share clear copy number changes with both tumour and other CS-CTCs; Type 2, where copy number changes were detected but were not shared with the tumour; Type 3, where no copy number changes were detected. Using WES of both CTCs and matching excised tumour regions, we identified common genetic alterations shared by CTCs and the tumour, as well as private genetic changes detected only in CTCs. We are currently evaluating metastatic biopsies from relapsing patients and comparing their molecular profiles to those seen in CS-CTCs obtained at surgery. Conclusion: The combined tumour and CTC data show that single CTC analysis provides an additional layer of complexity with a valuable new perspective on tumour heterogeneity and early dissemination in NSCLC. Citation Format: Francesca Chemi, Sakshi Gulati, Dominic G. Rothwell, Debbie Burt, Daniel Slan-Tan, Barbara Mesquita, Chris Wirth, Gareth Wilson, Jackie Pierce, Ged Brady, Charles Swanton, Caroline Dive. Single-cell molecular profiling of circulating tumor cells (CTCs) within the TRACERx study reveals heterogeneous patterns in early non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5601.

Introduction The cancer epigenome is a subject of intense research to identify new therapeutic targets and markers for diagnosis. Independent reports have showed that the cancer methylome is heterogeneous and that high levels of intra-tumour heterogeneity (ITH) correlate with poor prognosis. In this project, we aim to perform copy number profiling from bisulfite sequencing data and integrate allele specific copy number and purity estimates to deconvolve the pure tumour methylome and better our understanding of ITH and tumour evolution. Material and methods As part of the TRACERx study (TRAcking Cancer Evolution through therapy (Rx)), we analyse 38 cases of non-small cell lung cancer (NSCLC) with multi-region whole exome (WES) and reduced-representation bisulfite (RRBS) sequencing of the primary tumour for a total of 169 samples. We developed a novel bisulfite sequencing module for ASCAT (allele-specific copy number analysis of tumours), a method originally designed for SNP array data which computes the copy number profile of tumour cells, accounting for normal cell admixture and tumour aneuploidy. Results and discussions Tumour purity and copy number estimates were obtained using RRBS and validated using WES. We show that local copy number affects methylation rates extracted from the RRBS data in a way that can be modelled. If we have a CpG that is methylated in the tumour and unmethylated in the normal contaminating cells, the observed fraction of methylated reads in the bulk increases as a function of copy number given sample purity. Vice versa, the observed methylation rate will decrease with increasing tumour copy number when the tumour is unmethylated but the normal is methylated. Leveraging the observed relationship between methylation rate, copy number and tumour purity, we can extract the pure tumour methylation profiles from the RRBS data. The pure profiles allow for identification of differentially methylated regions (DMRs) between cancer and normal cells as well as between cancer subclones. We then reconstruct the evolutionary history of the tumour by hierarchal clustering of the DMRs. The obtained phylogenetic trees are validated by performing SNV clustering on the WES data. Conclusion We show that epigenetic ITH is present in NSCLC and integrate the cancer epigenome with other layers of ‘omics data to deepen our understanding of tumour evolution. Next, we aim to provide timing estimates for DMRs and identify potential drivers based on event recurrence and impact on gene expression from RNA-Seq data.

Cancer cells adopt a variety of mechanisms to evade the immune system and avoid T-cell recognition. Disruption of human leukocyte antigen (HLA), which may lead to reduced neoantigen presentation, has been proposed as an immune escape strategy in many cancers, including lung cancer. Mutations in HLA class I genes are infrequent in early stage non-small cell lung cancers (NSCLC), suggesting alternative mechanisms of HLA disruption may be common. To date, the polymorphic nature of the locus has precluded copy number analysis and exploration of HLA loss. To investigate the prevalence and importance of HLA disruption, we present LOHHLA (Loss Of Heterozygosity in Human Leukocyte Antigen), a computational tool to determine HLA allele-specific copy number from sequencing data. Building upon previous work imputing HLA haplotypes from sequencing data (Shukla, 2015; Szolek, 2014) and utilizing previously published datasets (Jamal-Hanjani, 2017; Brastianos, 2015), we endeavored to address the prevalence and timing of HLA LOH in lung cancer and its impact on tumor evolution and neoantigen presentation. Using LOHHLA, we find HLA LOH occurs in 40% of NSCLCs and is associated with a high subclonal neoantigen burden, APOBEC mediated-mutagenesis, upregulation of cytolytic activity and PD-L1 positivity. The focal nature of these alterations, their subclonal frequencies, enrichment in metastatic sites, and occurrence as parallel events suggest that HLA LOH is an immune escape mechanism, selected later in NSCLC tumor evolution. Characterizing HLA LOH with LOHHLA refines neoantigen prediction and may have implications for immunotherapeutic approaches targeting neoantigens. Citation Format: Nicholas McGranahan, Rachel Rosenthal, Crispin T. Hiley, Andrew J. Rowan, Thomas B.K. Watkins, Gareth A. Wilson, Nicolai J. Birkbak, Selvaraju Veeriah, Peter Van Loo, Javier Herrero, Charles Swanton. Allele specific HLA loss and immune escape in lung cancer evolution [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr LB-A03.

Nature 545, 446–451 (2017); doi:10.1038/nature22364 For 6 of the 96 patients included in this Article (patients CRUK0014, CRUK0030, CRUK0048, CRUK0059, CRUK0096 and CRUK0097) incorrect tumour volumetric data and positron emission tomography (PET) tumour background ratio (TBR) data were analysed. This error occurred because of the incorrect assignment of patient identifiers during the anonymization mandated by the independent review board of pre-operative computed tomography (CT) scans belonging to these patients.