Methods for detecting mutations using primer extension for detecting disease
First Claim
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1. A method for diagnosing colorectal cancer or precancer, the method comprising the steps of:
- performing an assay to detect, in a stool sample from a patient, a nucleic acid mutation indicative of a colorectal lesion;
performing a sigmoidoscopy on said patient; and
diagnosing colorectal cancer or precancer in said patient if at least one of said assay step and said sigmoidoscopy step is positive, wherein said nucleic acid mutation is a nucleic acid insertion or deletion, and wherein said assay comprises the steps of;
(a) selecting a nucleic acid having a known wild-type sequence and having a target region comprising a repeat sequence having at most three different types of nucleotide bases selected from the group consisting of dGTP, dATP, dTTP, and dCTP;
(b) contacting a sample with an oligonucleotide primer that is complementary to a portion of said nucleic acid immediately upstream of said target region;
(c) extending said primer in the presence of nucleotide bases that are complementary to the nucleotide bases of the target region, thereby to form a primer extension product;
(d) extending the primer extension product in the presence of a labeled nucleotide complementary to a nucleotide base downstream from the target region in said nucleic acid, wherein said labeled nucleotide is not complementary to any of the nucleotide bases of the target region selected in step (a), thereby to produce a labeled extension product comprising a sequence that is complementary to the entire target region;
(e) terminating the primer extension product by incorporating a terminator nucleotide in said product that is complementary to a nucleotide downstream from the target region in a wild type nucleic acid, wherein said terminator nucleotide is not complementary to any of the nucleotides of the target region selected in step (a), said step of terminating the primer extension product being performed simultaneously with or immediately after step (d);
(f) detecting the labeled extension product; and
(g) comparing the size of the labeled extension product detected in step (f) to a standard, wherein a labeled extension product smaller than the standard is indicative of the presence of a deletion in the target region and a labeled extension product larger than the standard is indicative of the presence of an insertion in the target region.
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Abstract
Methods of the invention comprise assays for markers indicative of cancer, precancer, and other diseases or disorders. Assays of the invention are preformed on heterogeneous samples obtained from patients by non-invasive or minimally-invasive methods. Such assays may be employed alone or in combination with other disease screening techniques
184 Citations
19 Claims
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1. A method for diagnosing colorectal cancer or precancer, the method comprising the steps of:
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performing an assay to detect, in a stool sample from a patient, a nucleic acid mutation indicative of a colorectal lesion;
performing a sigmoidoscopy on said patient; and
diagnosing colorectal cancer or precancer in said patient if at least one of said assay step and said sigmoidoscopy step is positive, wherein said nucleic acid mutation is a nucleic acid insertion or deletion, and wherein said assay comprises the steps of;
(a) selecting a nucleic acid having a known wild-type sequence and having a target region comprising a repeat sequence having at most three different types of nucleotide bases selected from the group consisting of dGTP, dATP, dTTP, and dCTP;
(b) contacting a sample with an oligonucleotide primer that is complementary to a portion of said nucleic acid immediately upstream of said target region;
(c) extending said primer in the presence of nucleotide bases that are complementary to the nucleotide bases of the target region, thereby to form a primer extension product;
(d) extending the primer extension product in the presence of a labeled nucleotide complementary to a nucleotide base downstream from the target region in said nucleic acid, wherein said labeled nucleotide is not complementary to any of the nucleotide bases of the target region selected in step (a), thereby to produce a labeled extension product comprising a sequence that is complementary to the entire target region;
(e) terminating the primer extension product by incorporating a terminator nucleotide in said product that is complementary to a nucleotide downstream from the target region in a wild type nucleic acid, wherein said terminator nucleotide is not complementary to any of the nucleotides of the target region selected in step (a), said step of terminating the primer extension product being performed simultaneously with or immediately after step (d);
(f) detecting the labeled extension product; and
(g) comparing the size of the labeled extension product detected in step (f) to a standard, wherein a labeled extension product smaller than the standard is indicative of the presence of a deletion in the target region and a labeled extension product larger than the standard is indicative of the presence of an insertion in the target region. - View Dependent Claims (2, 3, 4, 5, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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6. A method for localizing a colorectal lesion in a patient, the method comprising the steps of:
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performing an assay to detect, in a stool sample from a patient, a nucleic acid mutation indicative of said colorectal lesion;
performing a sigmoidoscopy on said patient;
diagnosing a proximal colonic lesion if said assay is positive for the mutation and said sigmoidoscopy is negative; and
diagnosing a distal colonic lesion if said sigmoidoscopy is positive and said assay is negative for the mutation, wherein said nucleic acid mutation is a nucleic acid insertion or deletion, and wherein said assay comprises the steps of;
(a) selecting a nucleic acid having a known wild-type sequence and having a target region comprising a repeat sequence having at most three different types of nucleotide bases selected from the group consisting of dGTP, dATP, dTTP, and dCTP;
(b) contacting a sample with an oligonucleotide primer that is complementary to a portion of said nucleic acid immediately upstream of said target region;
(c) extending said primer in the presence of nucleotide bases that are complementary to the nucleotide bases of the target region, thereby to form a primer extension product;
(d) extending the primer extension product in the presence of a labeled nucleotide complementary to a nucleotide base downstream from the target region in said nucleic acid, wherein said labeled nucleotide is not complementary to any of the nucleotide bases of the target region selected in step (a), thereby to produce a labeled extension product comprising a sequence that is complementary to the entire target region;
(e) terminating the primer extension product by incorporating a terminator nucleotide in said product that is complementary to a nucleotide downstream from the target region in a wild type nucleic acid, wherein said terminator nucleotide is not complementary to any of the nucleotides of the target region selected in step (a), said step of terminating the primer extension product being performed simultaneously with or immediately after step (d). (f) detecting the labeled extension product; and
(g) comparing the size of the labeled extension product detected in step (f) to a standard, wherein a labeled extension product smaller than the standard is indicative of the presence of a deletion in the target region and a labeled extension product larger than the standard is indicative of the presence of an insertion in the target region.
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7. A method for diagnosing hereditary non-polyposis colorectal cancer, the method comprising the steps of:
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performing an assay to detect, in a stool sample from a patient, a nucleic acid mutation indicative of said hereditary non-polyposis colorectal cancer;
performing a colonoscopy on said patient; and
diagnosing hereditary non-polyposis colorectal cancer if said assay is positive and said colonoscopy reveals an adenoma, wherein said nucleic acid mutation is a nucleic acid insertion or deletion, and wherein said assay comprises the steps of;
(a) selecting a nucleic acid having a known wild-type sequence and having a target region comprising a repeat sequence having at most three different types of nucleotide bases selected from the group consisting of dGTP, dATP, dTTP, and dCTP;
(b) contacting a sample with an oligonucleotide primer that is complementary to a portion of said nucleic acid immediately upstream of said target region;
(c) extending said primer in the presence of nucleotide bases that are complementary to the nucleotide bases of the target region, thereby to form a primer extension product;
(d) extending the primer extension product in the presence of a labeled nucleotide complementary to a nucleotide base downstream from the target region in said nucleic acid, wherein said labeled nucleotide is not complementary to any of the nucleotide bases of the target region selected in step (a), thereby to produce a labeled extension product comprising a sequence that is complementary to the entire target region;
(e) terminating the primer extension product by incorporating a terminator nucleotide in said product that is complementary to a nucleotide downstream from the target region in a wild type nucleic acid, wherein said terminator nucleotide is not complementary to any of the nucleotides of the target region selected in step (a), said step of terminating the primer extension product being performed simultaneously with or immediately after step (d). (f) detecting the labeled extension product; and
(g) comparing the size of the labeled extension product detected in step (f) to a standard, wherein a labeled extension product smaller than the standard is indicative of the presence of a deletion in the target region and a labeled extension product larger than the standard is indicative of the presence of an insertion in the target region.
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Specification