Blood cancers are together the 5th most common cancer and many patients are young adults. Besides, the most common cancers of childhood worldwide are acute lymphoblastic leukaemia and endemic Burkitt’s Lymphoma. Six of the 10 most lucrative cancer drugs are prescribed for haematological malignancies ($55.6billion by 2025). Their diagnosis requires a microscope and DNA-based precision diagnostics. But precision diagnostics is not always about identifying a simple base pair change, and requires the detection of all different types of mutations from one single (often small) patient sample. Examples of where DNA-based diagnostics are critical will be given and include all leukaemias and an increasing number of lymphomas. Their detection is recommended by the WHO classification of haematological malignancies. For example, the NHS test directory includes 177 different genetic aberrations.

The problem is that current multimodality testing in diagnostics laboratories is inadequate to deal with this demand on testing. Many of the conventional single gene assays lack sensitivity, speed and precision. Illumina whole genome sequencing (WGS) of tumour and paired germline has the potential to reveal all types of different mutations and global measures across the genome, but it is limited by the small fragment size and the need for large and expensive equipment. As part of the Genomics England Chronic Lymphocytic leukaemia Pilot have used information from Illumina WGS from 400 patients to develop an improved response prediction tool for chemoimmunotherapy that predicts patients who will be cured (manuscript in preparation). An alternative way specifically for diagnostics, is to combine targeted deep sequencing and error correction with shallow whole genome sequencing using the MinION. This method and variations of it can be applied globally in haematology. For example, the most common inherited anaemias, the haemoglobinopathies, are characterised by 1700 SNVs/indels and deletions across three genes. The most common of these, sickle cell disease, occurs in sub-Saharan Africa. About 10% of patients require confirmatory diagnosis by genetics. Life-saving therapies are available for this disease, and knowledge of the presence of the condition in the fetus could significantly streamline neonatal screening programmes around the world. We have clinically validated a proprietary method for non-invasive testing for sickle cell disease from maternal plasma (pre-published in BioRxiv) and have also developed a nanopore-based test for diagnosing haemoglobinopathies from germline DNA without the need for PCR amplification.

Finally, plasma-derived DNA can also be used in other clinical indications in sub-Saharan Africa. The most common childhood cancer in the region is endemic Burkitt’s lymphoma. This is caused by EBV infection in early childhood. With simple treatment, over 90% of patients can be cured. And treatment is free of charge in all African countries affected. Currently, over 90% of kids die. This is because children present late and are not diagnosed once in hospital because there is lack of trained surgeon and pathologists to establish the diagnosis from an invasive biopsy across the region. We are now clinically validating a non-invasive method to diagnose this type of lymphoma from the blood using a combination of tumour and virus sequencing.

In conclusion: haematological diseases have always spearheaded innovations and discoveries in medicine, in particular genetics. Precision medicine is a reality for an increasing number of patients with blood diseases from targeted small molecules in leukaemias and lymphomas to gene therapy in the inherited blood diseases. The next step is to leapfrog diagnostics technologies and to introduce these advances globally as expensive cancer therapies are coming off patent and are increasingly available and on the WHO list of essential medicines. Ultimately, this approach will achieve a huge impact for a large number of patients world-wide.
 

Epstein-Barr virus (EBV) infects the vast majority of the human population. In rare instances EBV is involved in the generation of lymphomas and other malignancies. The presence of elevated EBV levels in blood is currently used in the clinical diagnosis and subclassification of infectious disease and lymphoma; yet when patients present with detectible EBV in blood, it is uncertain if this represents an active infection or an evolving malignancy. Epigenetic changes occur as an essential component of the EBV life cycle, controlling the virus’s ability to infect, establish a chronic (latent) infected population of cells, and later reactivate to produce infectious virions. We have found that tumor-derived EBV DNA displays specific DNA methylation signatures and EBV virion-derived infectious particles or lytically-active (virus-replicating) cells contain largely unmethylated EBV DNA. Importantly, tumor-specific EBV methylation patterns are maintained in circulating plasma (cell-free) DNA. We have employed nanopore sequencing to interpret EBV DNA methylation signatures in patients. Analysis of tumor and plasma-derived EBV methylomes from lymphoma patients and donors with infectious EBV revealed highly discernable DNA methylation signatures, with higher levels of methylation in primary EBV+ lymphoma cases. In addition, we have uncovered an unexpectedly high complexity of EBV methylation patterns among tumors and evidence that epigenetic differences correlate with viral gene expression. These data may predict responses to combined antiviral and immunotherapeutic strategies in cancer patients. In summary, our work aims to develop approaches that harness a patient’s EBV epigenetic signature with the aid of nanopore sequencing to rapidly discern benign versus cancerous clinical scenarios and help direct the use of current and novel therapies.

From the battery of over 170 known RNA modifications, more than 70 have already been linked to human diseases, including neurological disorders and cancer, highlighting their importance in proper cellular functioning. Unfortunately, the limited availability of antibodies and chemicals selective to RNA modifications has so far limited our transcriptome-wide view to only a handful of RNA modifications. Consequently, the abundance, location, and function of the majority of RNA modifications remains unknown. To overcome these limitations, we have employed direct RNA sequencing from Oxford Nanopore Technologies, which allows direct sequencing of native RNA molecules, without any further amplification or reverse transcription step, thus potentially allowing for direct detection of RNA modifications in the full-length RNA transcripts. Using this technology, we have trained an algorithm that allows for the detection m6A RNA modifications in a quantitative manner and with single nucleotide resolution, finding that we can detect m6A RNA modifications with an overall accuracy of 90%. We then validate our findings in vivo, showing that our methodology can detect m6A modifications in yeast. As a control, we show that these modifications are not predicted by our algorithm in Ime4 knockout strains, which lack m6A. Our results open new avenues to investigate the universe of RNA modifications in full-length transcripts, with single molecule resolution. The establishment of the Oxford Nanopore platform as a tool to map virtually any given modification will allow us to query the epitranscriptome in ways that, until now, had not been possible. Future work can expand to other modifications like 5-methylcytosine (m5C), as well as provide additional thresholds for controlling specificity and sensitivity.

In many types of cancer, tumor cells shed small (~150bp) DNA molecules in the blood or other body fluids. Detecting mutations in the cell-free DNA (cfDNA) content of liquid biopsies in cancer patients thus offers a unique opportunity for non-invasive diagnostics for the purpose of e.g. treatment monitoring treatment response or detecting recurrent disease. Reliably detecting mutations from minute amounts of tumor derived cfDNA is, however, highly challenging. To address this, we developed CyclomicsSeq, a novel sequencing approach leveraging the long-read nanopore platform to achieve single molecule detection accuracy. We have demonstrated proof of concept on head and neck cancer (HNC) patient samples and found that CyclomicsSeq can detect mutations anywhere in the TP53 gene with single-molecule accuracy. CyclomicsSeq thus offers a reliable liquid biopsy diagnostic assay which can be cost-effectively implemented in routine clinical workflows. 

Release of the first human genome assembly was a landmark achievement, and after nearly two decades of improvements, the current human reference genome (GRCh38) is the most accurate and complete vertebrate genome ever produced. However, no one chromosome has yet been finished end to end, and hundreds of gaps persist across the genome. These unresolved regions include segmental duplications, ribosomal rRNA gene arrays, and satellite arrays that harbor unexplored variation of unknown consequence. We aim to finish these remaining regions and generate the first truly complete assembly of a human genome.

Here we announce a whole-genome de novo assembly that surpasses the continuity of GRCh38, along with the first complete, telomere-to-telomere assembly of a human X chromosome. In total, we collected 40X coverage of ultra-long Oxford Nanopore sequencing for the CHM13hTERT cell line, including 44 Gb of sequence in reads >100 kb and a maximum read length exceeding 1 Mb. This unprecedented coverage of ultra-long reads enabled the resolution of most repeats in the genome, including large fractions of the centromeric satellite arrays and short arms of the acrocentrics. A de novo assembly combining this nanopore data with 70X of existing PacBio data achieved an NG50 contig size of 75 Mb (compared to 56 Mb for GRCh38), with some chromosomes broken only at the centromere. Using this assembly as a basis, we chose to manually finish the X chromosome. The few unresolved segmental duplications were assembled using ultra-long reads spanning the individual copies, and the ~2.3 Mbp X centromere was assembled by identifying unique variants within the array and using these to anchor overlapping ultra-long reads. These results demonstrate that it is now possible to finish entire human chromosomes without gaps, and our future work will focus on completing and validating the remainder of the genome.

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Third generation DNA sequencing technologies have been transforming genome medicine and cancer research, producing evidences for structural variations (SV’s) being the common and major driver of complex diseases and tumorigenesis. By taking advantage of the un-parallelled power of long-read and high-throughput capability of the Oxford Nanopore PromethION platform, we investigated the role of SV’s in cancer development. We sequenced DNA obtained from colorectal cancer biopsy and corresponding normal tissue-samples of Han Chinese. Using a comprehensive SV-calling pipeline that consists of ngmlr-sniffle, dynamic filtering, database search and comparison, manual curation, and break point mapping, we obtained high quality SV call sets. By using PCA, population structure, and frequency spectrum analyses, we identified a set of SV’s that are tumor specific. In addition to somatic point mutations in mismatch repair genes that are well known for causing colorectal cancers, we observed complex somatic SV’s that show evidence of chromothriptic rearrangements, the hallmark of the late stage tumors, that were focally localized to a terminal region of a chromosome in colorectal cancer samples. One of the complex somatic rearrangements was linked to the amplification of the gene that is essential for DNA recombination. Furthermore, we also observed a direct link between the expansion of microsatellites and SV’s, suggesting the microsatellite instability might drive the formation of SV’s and cause genome instability in colorectal cancers. Collectively, our results present the power of the Oxford Nanopore PromethION platform for high resolution analysis of SV’s in the human genome, which can lead to a better understanding of the molecular, biochemical, and cellular events that govern tumor progression. 

Identifying the cellular pathways underlying psychiatric disorders has great potential to improve patient lives. Voltage-gated calcium channels (VGCCs), including CACNA1C, have been linked to the risk of bipolar disorder and schizophrenia, so are promising targets for new treatments. VGCCs are also important in the cardiovascular system, meaning treatments must be tissue-selective. We aim to identify brain-enriched CACNA1C isoforms as novel targets for new treatments. We used targeted long-range nanopore sequencing to characterise full length transcripts of CACNA1C in human brain and mouse brain, heart and aorta. In human we identified >250, and in mouse >190, mRNA isoforms, exons and splice junctions; including many predicted to modulate protein function. In mice, splicing was clearly tissue-specific, and we expect that this underlying principle of tissue-specific splicing will be conserved between mice and humans. Our data show that splicing of CACNA1C in human brain is far more diverse than is currently appreciated. This information will be critical to reveal pathophysiological mechanisms, and to identify brain-enriched VGCC isoforms that may be novel targets for new psychiatric treatments.

Retroviruses can integrate themselves into their host’s genome and become inherited, with about 8% of the human genome consisting of pieces of ancient retroviruses. Koala retrovirus (KoRV) is unusual for an inherited (endogenous) virus in that it is currently still undergoing the process of entering the genome and exists in both infectious and inherited forms. The virus has a major disease impact with up to 40% of captive animals dying from retroviral induced cancers. Animals in the north of Australia have a 100% prevalence of KoRV and all have the inherited form of the virus, those in the south of the country (a genetically distinct population) have a variable prevalence of the virus, a much lower rate of disease and some of them may have only the infectious form of the virus. Work we’ve done recently demonstrated that things are even more complicated than we thought with some animals having truncated forms of the virus that may be protective against the infectious forms. We’ve been unable to resolve the structure of these truncated forms with other methods so are using a combination of CRISPR and nanopore technologies to sequence these virus variants so that we can move on to working out if these can be used to protect these vulnerable wildlife populations from disease.