Patents by Inventor Kwan Chee Chan

Kwan Chee Chan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20170220736
    Abstract: Systems, apparatus, and methods are provided for determining aberrations in a biological sample from an organism. Biological samples including cell-free DNA fragments are analyzed to identify imbalances in chromosomal regions, e.g., due to deletions and/or amplifications in a tumor. Multiple loci are used for each chromosomal region. Imbalances can be used to diagnose a patient for cancer, prognosticate a patient with cancer, or to detect the presence or monitor progress of a premalignant condition. The severity of an imbalance as well as the number of regions exhibiting an imbalance can be used. A systematic analysis of non-overlapping segments of a genome can provide a general screening tool for a sample. Additionally, a patient can be tested over time to track severity of each of one or more chromosomal regions and a number of chromosomal regions to enable screening and prognosticating, as well as monitoring of progress (e.g. after treatment).
    Type: Application
    Filed: April 19, 2017
    Publication date: August 3, 2017
    Inventors: Yuk-Ming Dennis Lo, Kwan Chee Chan, Rossa Wai Kwun Chiu, Peiyong Jiang
  • Publication number: 20170218450
    Abstract: Methods, systems, and apparatus determine whether a first chromosomal region exhibits a deletion or an amplification associated with cancer in a sample from a subject (e.g., where the sample includes a mixture of cell-free DNA from tumor cells and non-malignant cells. Nucleic acid molecules of the biological sample are sequenced. Respective amounts of a clinically-relevant chromosomal region and of background chromosomal region(s) 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 first chromosomal region exhibits a deletion or an amplification associated with cancer.
    Type: Application
    Filed: March 30, 2017
    Publication date: August 3, 2017
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan
  • Publication number: 20170132363
    Abstract: A classification of a level of cancer in an organism is determined by analyzing a biological sample of the organism. The biological sample comprises clinically-relevant DNA and other DNA. At least some of the DNA is cell-free in the biological sample. An amount of a first set of DNA fragments from the biological sample corresponding to each of a plurality of sizes is measured. A first value of a first parameter is calculated based on the amounts of DNA fragments at the plurality of sizes. The first value is compared to a reference value. A classification of a level of cancer in the organism is determined based on the comparison.
    Type: Application
    Filed: January 20, 2017
    Publication date: May 11, 2017
    Inventors: Yuk Ming Dennis Lo, Wai Kwun Rossa Chiu, Kwan Chee Chan, Wenli Zheng, Peiyong Jiang, Jiawei Liao
  • Publication number: 20170081720
    Abstract: 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.
    Type: Application
    Filed: September 22, 2016
    Publication date: March 23, 2017
    Inventors: Yuk-Ming Dennis Lo, Peiyong Jiang, Kwan Chee Chan, Rossa Wai Kwun Chiu
  • Publication number: 20170073774
    Abstract: Embodiments are related to the accurate detection of somatic mutations in the plasma (or other samples containing cell-free DNA) of cancer patients and for subjects being screened for cancer. The detection of these molecular markers would be useful for the screening, detection, monitoring, management, and prognostication of cancer patients. For example, a mutational load can be determined from the identified somatic mutations, and the mutational load can be used to screen for any or various types of cancers, where no prior knowledge about a tumor or possible cancer of the subject may be required. Embodiments can be useful for guiding the use of therapies (e.g. targeted therapy, immunotherapy, genome editing, surgery, chemotherapy, embolization therapy, anti-angiogenesis therapy) for cancers. Embodiments are also directed to identifying de novo mutations in a fetus by analyzing a maternal sample having cell-free DNA from the fetus.
    Type: Application
    Filed: November 28, 2016
    Publication date: March 16, 2017
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan, Peiyong Jiang
  • Publication number: 20170029900
    Abstract: 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.
    Type: Application
    Filed: July 20, 2016
    Publication date: February 2, 2017
    Inventors: Yuk-Ming Dennis Lo, Kwan Chee Chan, Rossa Wai Kwun Chiu, Peiyong Jiang, Kun Sun
  • Publication number: 20170024513
    Abstract: Factors affecting the fragmentation pattern of cell-free DNA (e.g., plasma DNA) and the applications, including those in molecular diagnostics, of the analysis of cell-free DNA fragmentation patterns are described. Various applications can use a property of a fragmentation pattern to determine a proportional contribution of a particular tissue type, to determine a genotype of a particular tissue type (e.g., fetal tissue in a maternal sample or tumor tissue in a sample from a cancer patient), and/or to identify preferred ending positions for a particular tissue type, which may then be used to determine a proportional contribution of a particular tissue type.
    Type: Application
    Filed: July 25, 2016
    Publication date: January 26, 2017
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan, Peiyong Jiang
  • Patent number: 9512480
    Abstract: Systems, methods, and apparatus for determining at least a portion of fetal genome are provided. DNA fragments from a maternal sample (maternal and fetal DNA) can be analyzed to identify alleles at certain loci. The amounts of DNA fragments of the respective alleles at these loci can be analyzed together to determine relative amounts of the haplotypes for these loci and determine which haplotypes have been inherited from the parental genomes. Loci where the parents are a specific combination of homozygous and heterozygous can be analyzed to determine regions of the fetal genome. Reference haplotypes common in the population can be used along with the analysis of the DNA fragments of the maternal sample to determine the maternal and paternal genomes. Determination of mutations, a fractional fetal DNA concentration in a maternal sample, and a proportion of coverage of a sequencing of the maternal sample can also be provided.
    Type: Grant
    Filed: May 15, 2013
    Date of Patent: December 6, 2016
    Assignees: The Chinese University of Hong Kong, Sequenom Inc.
    Inventors: Yuk Ming Dennis Lo, Kwan Chee Chan, Wai Kwun Rossa Chiu, Charles Cantor
  • Publication number: 20160217251
    Abstract: 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.
    Type: Application
    Filed: January 12, 2016
    Publication date: July 28, 2016
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan, Peiyong Jiang, Cheuk Yin Jandy Yu
  • Publication number: 20160203260
    Abstract: An amount of mitochondrial DNA molecules relative to an amount of nuclear DNA molecules is determined in a biological sample, and the relative amount is used for various purposes, e.g., screening, detection, prognostication or monitoring of various physiological and pathological conditions. As examples, an amount of mitochondrial DNA can be used to estimate a concentration of DNA of a tissue type, such as a fetal DNA concentration, tumor DNA concentration, or a concentration of DNA in the biological sample derived from a non-hematopoietic tissue source. Sequencing techniques can be used to determine a mitochondrial DNA concentration in a sample for an accurate detection of a level of cancer. A level of an auto-immune disease is also determined using a relative amount of mitochondrial DNA molecules compared nuclear DNA molecules.
    Type: Application
    Filed: January 12, 2016
    Publication date: July 14, 2016
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan, Peiyong Jiang
  • Publication number: 20160201142
    Abstract: Analysis of tumor-derived circulating cell-free DNA opens up new possibilities for performing liquid biopsies for solid tumor assessment or cancer screening. However, many aspects of the biological characteristics of tumor-derived cell-free DNA remain unclear. Regarding the size profile of plasma DNA molecules, some studies reported increased integrity of tumor-derived plasma DNA while others reported shorter tumor-derived plasma DNA molecules. We performed an analysis of the size profiles of plasma DNA in patients with cancer using massively parallel sequencing at single base resolution and in a genomewide manner. Tumor-derived plasma DNA molecules were further identified using chromosome arm-level z-score analysis (CAZA). We showed that populations of aberrantly short and long DNA molecules co-existed in the plasma of patients with cancer. The short ones preferentially carried the tumor-associated copy number aberrations. These results show the ability to use plasma DNA as a molecular diagnostic tool.
    Type: Application
    Filed: January 12, 2016
    Publication date: July 14, 2016
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan, Peiyong Jiang
  • Publication number: 20160201134
    Abstract: Whether a fetus has an aneuploidy associated with a first chromosome is detected using ratios of alleles detected in a maternal sample having a mixture of maternal and fetal DNA. DNA from the sample is enriched for target regions associated with polymorphic loci and then sequenced. Polymorphic loci (e.g., single nucleotide polymorphisms) in the target regions with fetal-specific alleles are identified on a first chromosome and on one or more reference chromosomes. A first ratio of the fetal-specific alleles and shared alleles is determined for the loci on the first chromosome. A second ratio of the fetal-specific alleles and shared alleles is determined for the loci on the reference chromosome(s). A third ratio of the first and second ratio can be compared to a cutoff to determine whether an aneuploidy is present, and whether the aneuploidy is maternally-derived or paternally-derived.
    Type: Application
    Filed: March 21, 2016
    Publication date: July 14, 2016
    Inventors: Jiawei Liao, Kwan Chee Chan, Wai Kwun Rossa Chiu, Yuk Ming Dennis Lo
  • Publication number: 20160017419
    Abstract: The contributions of different tissues to a DNA mixture are determined using methylation levels at particular genomic sites. Tissue-specific methylation levels of M tissue types can be used to deconvolve mixture methylation levels measured in the DNA mixture, to determine fraction contributions of each of the M tissue types. Various types of genomic sites can be chosen to have particular properties across tissue types and across individuals, so as to provide increased accuracy in determining contributions of the various tissue types. The fractional contributions can be used to detect abnormal contributions of a particular tissue, indicating a disease state for the tissue. A differential in fractional contributions for different sizes of DNA fragments can also be used to identify a diseased state of a particular tissue. A sequence imbalance for a particular chromosomal region can be detected in a particular tissue, e.g., identifying a location of a tumor.
    Type: Application
    Filed: July 20, 2015
    Publication date: January 21, 2016
    Inventors: Rossa Wai Kwun Chiu, Kwan Chee Chan, Yuk-Ming Dennis Lo, Peiyong Jiang, Kun Sun
  • Patent number: 9218449
    Abstract: This invention provides several ways of managing GC bias that occurs during seequencing and analysis of genomic DNA. Maternal plasma can be used as a source of fetal DNA for analysis. DNA segments or tags obtained from the plasma can be aligned with a chromosomal region of interest and with an artificial reference chromosome assembled from regions of the genome having matching GC content. This technology can be used, for example, to detect and evaluate aneuploidy and other chromosomal abnormalities.
    Type: Grant
    Filed: March 13, 2013
    Date of Patent: December 22, 2015
    Assignee: The Chinese University of Hong Kong
    Inventors: Yuk Ming Dennis Lo, Wai Kwun Rossa Chiu, Kwan Chee Chan, Wenli Zheng, Hao Sun, Zhang Chen
  • Patent number: 9121069
    Abstract: Methods, systems, and apparatus determine whether a first chromosomal region exhibits a deletion or an amplification associated with cancer in a sample from a subject (e.g., where the sample includes a mixture of cell-free DNA from tumor cells and non-malignant cells. Nucleic acid molecules of the biological sample are sequenced. Respective amounts of a clinically-relevant chromosomal region and of background chromosomal region(s) 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 first chromosomal region exhibits a deletion or an amplification associated with cancer.
    Type: Grant
    Filed: July 8, 2013
    Date of Patent: September 1, 2015
    Assignee: The Chinese University of Hong Kong
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan
  • Patent number: 9051616
    Abstract: 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.
    Type: Grant
    Filed: July 18, 2014
    Date of Patent: June 9, 2015
    Assignee: The Chinese University of Hong Kong
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan
  • Patent number: 8972202
    Abstract: 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.
    Type: Grant
    Filed: July 18, 2014
    Date of Patent: March 3, 2015
    Assignee: The Chinese University of Hong Kong
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan
  • Publication number: 20150011403
    Abstract: 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.
    Type: Application
    Filed: September 24, 2014
    Publication date: January 8, 2015
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan, Miu Fan Lun, Wai Man Chan, Peiyong Jiang
  • Patent number: 8927216
    Abstract: This application describes the discovery that, in a pregnant woman, certain genes (such as RASSF1A, APC, CASP8, RARB, SCGB3A1, DAB2IP, PTPN6, THY1, TMEFF2, and PYCARD) originated from a fetus are highly methylated, whereas the same genes of maternal origin are unmethylated. This discovery allows the easy detection of one or more of these methylated fetal genes in a biological sample from a pregnant woman, serving as a universal indicator of the presence of fetal DNA in the sample. These fetal methylation markers are particularly useful as positive controls for a non-invasive analytical process during which the quality and quantity of fetal DNA are monitored. These newly identified fetal markers can also be measured directly for diagnosis of certain pregnancy-related conditions.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: January 6, 2015
    Assignee: The Chinese University of Hong Kong
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Stephen Siu Chung Chim, Chunming Ding, Kwan Chee Chan, Hing Nam Ivy Wong, Ka Chun Ryan Yuen
  • Publication number: 20140329695
    Abstract: 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.
    Type: Application
    Filed: July 18, 2014
    Publication date: November 6, 2014
    Applicant: The Chinese University of Hong Kong
    Inventors: Yuk-Ming Dennis Lo, Rossa Wai Kwun Chiu, Kwan Chee Chan