The Chinese University of Hong Kong

Grail, Inc.

Sequenom, Inc.

Centre for Novostics

Kwan Chee Chan

Rossa Wai Kwun Chiu

Yuk-Ming Dennis Lo

Peiyong Jiang

Yuk Ming Dennis Lo

Wai Kwun Rossa Chiu

Wenli Zheng

Kun Sun

Wai Kei Lam

Jiawei Liao

Suk Hang Cheng

Wenlei Peng

Wai Man Chan

Miu Fan Lun

Charles Cantor

Cheuk Yin Jandy Yu

Ka Chun Chong

Chunming Ding

Stephen Siu Chung Chim

Bo Yin Tsui

Lu Ji

Cheuk Yin Yu

Yee Ting Cheung

Benny Chung Ying Zee

Hing Nam Ivy Wong

Ka Chun Ryan Yuen

On Yee Tse

Haiqiang Zhang

Eugeni A Namsaraev

Benny Chung-Ying Zee

Tak Yeung Leung

Rossa Wai Kun Chiu

Jiaen Deng

Qing Zhou

Rong Qiao

Weng In Chu

Guannan Kang

Tsz Kwan Sin

Wanxia Gai

Hua Tse Timothy Cheng

Zhang Chen

Hao Sun

Wai Kwon Rossa Chiu

Wai Kwun Rossa Chu

Wing Yan Chan

Rossa Wai Chiu

Ka Chun Yuen

Hing Nam Wong

Stephen Siu Chim

Yuk Ming Lo

Systems, methods, and apparatuses can determine and use methylation profiles of various tissues and samples. Examples are provided. A methylation profile can be deduced for fetal/tumor tissue based on a comparison of plasma methylation (or other sample with cell-free DNA) to a methylation profile of the mother/patient. A methylation profile can be determined for fetal/tumor tissue using tissue-specific alleles to identify DNA from the fetus/tumor when the sample has a mixture of DNA. A methylation profile can be used to determine copy number variations in genome of a fetus/tumor. Methylation markers for a fetus have been identified via various techniques. The methylation profile can be determined by determining a size parameter of a size distribution of DNA fragments, where reference values for the size parameter can be used to determine methylation levels. Additionally, a methylation level can be used to determine a level of cancer.

Non-invasive detection of tissue abnormality using methylation

Provided herein are methods, systems, and computer readable medium for detecting nucleic acid from a pathogen, e.g., virus, e.g., Epstein-Barr virus (EBV), in a cell-free nucleic sample from an individual at risk of a condition, e.g., nasopharyngeal carcinoma (NPC). The methods, systems, and computer readable medium can be used to screen for the presence of the condition, e.g., NPC, using thresholds adjusted based on sample attributes.

Methods for analyzing viral nucleic acid

Systems, apparatuses, and method are provided for determining the contributions of different tissues to a biological sample that includes a mixture of cell-free DNA molecules from various tissues types, e.g., as occurs in plasma or serum and other body fluids. Embodiments can analyze the methylation patterns of the DNA mixture (e.g., methylation levels at particular loci) for a particular haplotype and determine fractional contributions of various tissue types to the DNA mixture, e.g., of fetal tissue types or tissue types of specific organs that might have a tumor. Such fractional contributions determined for a haplotype can be used in a variety of ways.

Methylation pattern analysis of haplotypes in tissues in a DNA mixture

Fragmentation of cell-free DNA molecules is measured and used for various purposes, including determining methylation, e.g., at a particular site of a DNA molecule, at a particular genomic site in a reference genome for a biological sample (e.g., plasma, serum, urine, saliva) of cell-free DNA of a subject, or for a particular region in the reference genome for the biological sample (also just referred to as a sample). Various types of fragmentation measurements can be used, e.g., end motifs and cleavage profiles. Another purpose is determining a fractional concentration of DNA of a particular tissue type (e.g., clinically-relevant DNA). Another purpose is determining a pathology of a subject using a biological sample including cell-free DNA. The cell-free DNA can be of the subject or of a pathogen (e.g., a virus) in the subject's sample. Sites/regions that are hypermethylated, hypomethylated, 5hmC-enriched, and 5hmC-depleted for a particular tissue type can be used.

Fragmentation for measuring methylation and disease

Size-band analysis is used to determine whether a chromosomal region exhibits a copy number aberration or an epigenetic alteration. Multiple size ranges may be analyzed instead of focusing on specific sizes. By using multiple size ranges instead of specific sizes, methods may analyze more sequence reads and may be able to determine whether a chromosomal region exhibits a copy number aberration even when clinically-relevant DNA may be a low fraction of the biological sample. Using multiple ranges may allow for the use of all sequence reads from a genomic region, rather than a selected subset of reads in the genomic region. The accuracy of analysis may be increased with higher sensitivity at similar or higher specificity. Analysis may include fewer sequencing reads to achieve the same accuracy, resulting in a more efficient process.

Using nucleic acid size range for noninvasive cancer detection

Cell-free DNA molecules in a mixture of a biological sample can be analyzed to detect viral DNA. Methylation of viral DNA molecules at one or more sites in the viral genome can be determined. Mixture methylation level(s) can be measured based on one or more amounts of the plurality of cell-free DNA molecules methylated at a set of site(s) of the particular viral genome. The mixture methylation level(s) can be determined in various ways, e.g., as a density of cell-free DNA molecules that are methylated at a site or across multiple sites or regions. The mixture methylation level(s) can be compared to reference methylation level(s), e.g., determined from at least two cohorts of other subjects. The cohorts can have different classifications (including the first condition) associated with the particular viral genome. A first classification of whether the subject has the first condition can be determined based on the comparing.

Enhancement of cancer screening using cell-free viral nucleic acids

Methods, systems, and apparatus are provided for determining whether a nucleic acid sequence imbalance exists within a biological sample. One or more cutoff values for determining an imbalance of, for example, the ratio of the two sequences (or sets of sequences) are chosen. The cutoff value may be determined based at least in part on the percentage of fetal DNA in a sample, such as maternal plasma, containing a background of maternal nucleic acid sequences. The percentage of fetal DNA can be calculated from the same or different data used to determine the cutoff value, and can use a locus where the mother is homozygous and the fetus is heterozygous. The cutoff value may be determined using many different types of methods, such as sequential probability ratio testing (SPRT).

Determining a nucleic acid sequence imbalance associated with cancer using multiple markers

An aberration in a fetal genome can be identified by analyzing a sample of fetal and maternal DNA. Classifications of whether an aberration (amplification or deletion) exists in a subchromosomal region are determined using count-based and size-based methods. The count classification and the size classification can be used in combination to determine whether only the fetus or only the mother, or both, have the aberration in the subchromosomal region, thereby avoiding false positives when the mother has the aberration and the fetus does not.

Combined size- and count-based analysis of maternal plasma for detection of fetal subchromosomal aberrations

Embodiments of this invention provide methods, systems, and apparatus for determining whether a fetal chromosomal aneuploidy exists from a biological sample obtained from a pregnant female. Nucleic acid molecules of the biological sample are sequenced, such that a fraction of the genome is sequenced. Respective amounts of a clinically-relevant chromosome and of background chromosomes are determined from results of the sequencing. The determination of the relative amounts may count sequences of only certain length. A parameter derived from these amounts (e.g. a ratio) is compared to one or more cutoff values, thereby determining a classification of whether a fetal chromosomal aneuploidy exists. Prior to sequencing, the biological sample may be enriched for DNA fragments of a particular sizes.

Diagnosing fetal chromosomal aneuploidy using genomic sequencing

Methods and systems described herein involve using long cell-free DNA fragments to analyze a biological sample from a pregnant subject. The status of methylated CpG sites and single nucleotide polymorphisms (SNPs) is often used to analyze DNA fragments of a biological sample. A CpG site and a SNP are typically separated from the nearest CpG site or SNP by hundreds or thousands of base pairs. Finding two or more consecutive CpG sites or SNPs on most cell-free DNA fragments is improbable or impossible. Cell-free DNA fragments longer than 600 bp may include multiple CpG sites and/or SNPs. The presence of multiple CpG sites and/or SNPs on long cell-free DNA fragments may allow for analysis than with short cell-free DNA fragments alone. The long cell-free DNA fragments can be used to identify a tissue of origin and/or to provide information on a fetus in a pregnant female.

Molecular analyses using long cell-free fragments in pregnancy

Techniques are provided for analyzing circular DNA in a biological sample (e.g., including cell-free DNA, such as plasma). For example, to measure circular DNA, cleaving can be performed to linearize the circular DNA so that they may be sequenced. Example cleaving techniques include restriction enzymes and transposases. Then, one or more criteria can be used to identify linearized DNA molecules, e.g., so as to differentiate from linear DNA molecules. An example criterion is mapping a pair of reversed end sequences to a reference genome. Another example criterion is identification of a cutting tag, e.g., associated with a restriction enzyme or an adapter sequence added by a transposase. Once circular DNA molecules (e.g., eccDNA and circular mitochondrial DNA) are identified, they may be analyzed (e.g., to determine a count, size profile, and/or methylation) to measure a property of the biological sample, including genetic properties and level of a disease.

Determining linear and circular forms of circulating nucleic acids

Diagnosing fetal chromosomal aneuploidy using massively parallel genomic sequencing

Embodiments of the present invention provide methods, systems, and apparatus for deducing the fetal DNA fraction in maternal plasma without using paternal or fetal genotypes. Maternal genotype information may be obtained from a maternal-only DNA sample or may be assumed from shallow-depth sequencing of a biological sample having both maternal and fetal DNA molecules. Because sequencing may be at shallow depths, a locus may have only few reads and may fail to exhibit a non-maternal allele even if a non-maternal allele is present. However, normalized parameters that characterize non-maternal alleles sequenced can be used to provide an accurate estimate of the fetal DNA fraction, even if the amount of non-maternal alleles is in error. Methods described herein may not need high-depth sequencing or enrichment of specific regions. As a result, these methods can be integrated into widely used non-invasive prenatal testing and other diagnostics.

Accurate deduction of fetal DNA fraction with shallow-depth sequencing of maternal plasma

Embodiments of this invention provide methods, systems, and apparatus for determining whether a fetal chromosomal aneuploidy exists from a biological sample obtained from a pregnant female. Nucleic acid molecules of the biological sample are sequenced, such that a fraction of the genome is sequenced. Respective amounts of a clinically-relevant chromosome and of background chromosomes are determined from results of the sequencing. A parameter derived from these amounts (e.g. a ratio) is compared to one or more cutoff values, thereby determining a classification of whether a fetal chromosomal aneuploidy exists.

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Shatin, China

Kwan Chee Chan