Project description:Set of 19 patients afflicted with colorectal cancer with matching preoperative and postoperative blood plasma, PBMC, and tumor biopsy sequencing data. Originally referenced by Genome-wide cell-free DNA mutational integration enables ultra-sensitive cancer monitoring. Nat Med. 2020, Zviran et. al.
Project description:In many areas of oncology, we lack sensitive tools to track low burden disease. While cell-free DNA (cfDNA) shows promise in detecting cancer mutations, we found that the combination of low tumor fraction (TF) and limited number of DNA fragments restricts low disease burden monitoring through the prevailing deep targeted sequencing paradigm. We reasoned that breadth may supplant depth of sequencing to overcome the barrier of cfDNA abundance. Whole genome sequencing (WGS) of cfDNA allowed ultra-sensitive detection, capitalizing on the cumulative signal of thousands of somatic mutations observed in solid malignancies, with TF detection sensitivity as low as 10-5. The WGS approach enabled dynamic tumor burden tracking and post-operative residual disease detection, associated with adverse outcome. Thus, we present an orthogonal framework for cfDNA cancer monitoring via genome wide mutational integration, enabling ultra-sensitive detection, overcoming the limitation of cfDNA abundance, and empowering treatment optimization in low-disease burden oncology care
Project description:Regenerative cell therapies and stem-based in vitro models all aspire the approximation of a given start cell to an alternate (often more mature) cell state. However, ‘monitoring’, hence controlling, such a dynamic process requires disruption of the precious sample, destroying architecture and introducing variation. Here, we establish real time-compatible, fully non-invasive monitoring of cell fates through simple cell-free DNA medium sampling. We demonstrate that cell-free DNA methylation non-disruptively reveals genome-wide DNA methylation transitions during epigenetic drug treatment in stem cells, and reports the gradual maturation of 3D hepatocytes grown in bioreactors. Our cell-free DNA methylation platform enables monitoring a broad variety of in vitro systems, has implications for the real-time evaluation human therapeutic cells, and the potential to be readily integrated into large-scale bioreactor workflows.
Project description:Mapping genome-wide 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) at single-base resolution is important to understand their biological functions. We present a cost-efficient mapping method that combines 5hmC-specific restriction enzyme PvuRts1I with a 5hmC enrichment method. The sensitive method enables detection of low abundant 5hmC sites, providing a more complete 5hmC landscape than available bisulfite-based methods. This method generated the first genome-wide 5fC map at single-base resolution. Parallel analyses revealed that 5hmC and 5fC existed with lower abundance and more dynamically in non-CpG context than in CpG context. In the genic region, distribution of 5hmCpG and 5fCpG differed from 5hmCH and 5fCH (H=A, T, C). 5hmC and 5fC were distributed distinctly at regulatory protein-DNA binding sites, depleted in permissive transcription factor binding sites, and enriched at active and poised enhancers. This sensitive bisulfite-conversion free method can be applied to biological samples with limited starting material or low abundance of cytosine modifications. Sensitive mapping of genome-wide 5-hydroxymethylcytosine and 5-formylcytosine in mouse embryonic stem cell at single-base resolution by combining 5-hydroxymethylcytosine specific restriction enzyme PvuRts1I and 5-hydroxymethylcytosine enrichment method (selective chemical labeling or SEAL)
Project description:Cerebrospinal fluid (CSF) liquid biopsies serve as a rich source of tumor-derived cell-free DNA (cfDNA) for evaluating patients with central nervous system (CNS) tumors. However, challenges stemming from trace cfDNA yields and low mutational burden have hindered sensitivity, whereas first-generation clinical assays have relied on genetic alterations as biomarkers. Leveraging the diagnostic utility of DNA methylation classification in CNS tumors, we developed M-PACT (Methylation-based Predictive Algorithm for CNS Tumors), a robust deep neural network that accurately classifies tumors from sub-nanogram input cfDNA methylomes acquired through enzymatic methylation sequencing. In addition to tumor classification, this workflow enables methylation-based cellular deconvolution and sensitive copy number variation (CNV) detection. We benchmark our methodology in pediatric CNS embryonal tumors and further demonstrate accurate classification of intra-operative CSF, balanced tumor genomes, and secondary malignancies. Altogether, we provide a blueprint for CNS tumor classification from low input cfDNA methylomes, motivating prospective validation for future clinical implementation.
Project description:Genome-wide analysis of cell-free DNA (cfDNA) methylation profile has been recognized as a promising approach for sensitive and specific detection of many cancers. However, scaling such genome-wide assays for clinical translation is impractical due to the high cost of whole genome bisulfite sequencing. We have shown that the small fraction of GC-rich genome is highly enriched in CpG sites and disproportionately harbors the majority of cancer-specific methylation signature. Here, we report on the simple but effective Heat enrichment of CpG-rich regions for Bisulfite Sequencing (Heatrich-BS) platform that allows for focused methylation profiling in these highly informative regions. Our novel method and bioinformatics algorithm enable accurate tumor burden estimation with high sensitivity and quantitative tracking of colorectal cancer patient’s response to treatment, at much reduced sequencing cost suitable for frequent monitoring. We also show, for the first time, tumor epigenetic subtyping from cfDNA using Heatrich-BS, which could enable patient stratification from non-invasive liquid biopsy. As such, Heatrich-BS holds great potential for highly scalable screening and regular monitoring of cancer using liquid biopsy.
Project description:Genome-wide analysis of cell-free DNA (cfDNA) methylation profile has been recognized as a promising approach for sensitive and specific detection of many cancers. However, scaling such genome-wide assays for clinical translation is impractical due to the high cost of whole genome bisulfite sequencing. We have shown that the small fraction of GC-rich genome is highly enriched in CpG sites and disproportionately harbors the majority of cancer-specific methylation signature. Here, we report on the simple but effective Heat enrichment of CpG-rich regions for Bisulfite Sequencing (Heatrich-BS) platform that allows for focused methylation profiling in these highly informative regions. Our novel method and bioinformatics algorithm enable accurate tumor burden estimation with high sensitivity and quantitative tracking of colorectal cancer patient’s response to treatment, at much reduced sequencing cost suitable for frequent monitoring. We also show, for the first time, tumor epigenetic subtyping from cfDNA using Heatrich-BS, which could enable patient stratification from non-invasive liquid biopsy. As such, Heatrich-BS holds great potential for highly scalable screening and regular monitoring of cancer using liquid biopsy.