SENSITIVITY OF TUMOR-INFORMED MINIMAL RESIDUAL DISEASE PANELS
Described herein are methods for improving sensitivity of tumor-informed MRD assays and panels by prioritizing sites to generate patient-specific panel of somatic variants based on expected variant allele frequency such that tumor somatic variants are overrepresented in cfDNA. Machine learning models trained with genomic data are also utilized to select the subset of somatic variants alone or in combination with an expected variant allele frequency.
1 . A method of preparing a probe set for enriching circulating tumor DNA (ctDNA) from a sample, comprising:
sequencing DNA obtained from a tumor sample from a cancer patient and sequencing DNA obtained from a non-tumor sample from the cancer patient, thereby obtaining sequences of DNA from the tumor sample and sequences of DNA from the non-tumor sample;
determining somatic variants based on differences between sequences of DNA from the tumor sample and sequences of DNA from the non-tumor sample;
calculating, using a computer processor, an expected variant allele frequency based on copy number and allele balance of each of the somatic variants;
selecting a subset of somatic variants for which the expected variant allele frequency is above a reference threshold; and
preparing a probe set comprising a plurality of oligonucleotides, wherein each oligonucleotide in the plurality of oligonucleotides comprises a nucleic acid sequence that is capable of hybridizing to a DNA fragment comprising one of the subset of somatic variants for which the expected variant allele frequency is above a reference threshold.
2 . The method of claim 2 further comprising:
sequencing cell-free DNA (cfDNA) extracted from at least one further sample of blood, plasma, or serums from the cancer patient, thereby obtaining a plurality of sequence reads; and
detecting in the plurality of sequence reads a sequence read comprising any one of the subset of somatic variants, thereby detecting the presence of ctDNA in the at least one further sample.
3 . (canceled)
4 . A method comprising:
(a) retrieving, by a processor, data associated with a tumor sample and a non-tumor sample from a cancer patient;
(b) generating, by the processor, a training data set comprising sequenced DNA from the tumor sample, sequenced DNA from the non-tumor sample, and somatic variants based on differences between sequences of DNA from the tumor sample and sequences of DNA from the non-tumor sample; and
(c) training, by the processor, a machine learning model using the training dataset, such that the machine learning model is configured to ingest data associated with a second tumor sample and a second non-tumor sample from a patient and predict a subset of somatic variants that are suitable for isolating ctDNA for the patient.
5 . (canceled)
6 . A method of detecting circulating tumor DNA (ctDNA) in a sample, comprising:
sequencing DNA obtained from a tumor sample from a cancer patient and sequencing DNA obtained from a non-tumor sample from the cancer patient, thereby obtaining sequences of DNA from the tumor sample and sequences of DNA from the non-tumor sample;
determining a set of somatic variants based on differences between sequences of DNA from the tumor sample and sequences of DNA from the non-tumor sample;
selecting a subset of somatic variants that are suitable for enriching ctDNA by:
(i) calculating, using a computer processor, an expected variant allele frequency based on copy number and allele balance of each of the somatic variants in the set of somatic variants, and selecting somatic variants for which the expected variant allele frequency is above a reference threshold,
(ii) determining, based on a plurality of features of the set of somatic variants, a subset of somatic variants that are suitable for enriching ctDNA, wherein the plurality of features are selected by a machine learning model trained with genomic data, or
(iii) a combination of (i) and (ii); and
sequencing cell-free DNA (cfDNA) extracted from at least one further sample of blood, plasma, or serums from the cancer patient, thereby obtaining a plurality of sequence reads; and
detecting in the plurality of sequence read a sequence read comprising any one of the subset of somatic variants, thereby detecting the presence of ctDNA in the at least one further sample.
7 .- 8 . (canceled)
9 . The method of claim 2 , further comprising enriching the extracted cfDNA prior to sequencing by contacting the extracted cfDNA with a plurality of oligonucleotides, wherein each oligonucleotide in the plurality of oligonucleotides comprises a nucleic acid sequence that is capable of hybridizing to a DNA fragment comprising one of the somatic variants, thereby obtaining a ctDNA-enriched fraction;
optionally wherein the enriching comprises (i) hybrid capture-based enrichment, (ii) PCR-target enrichment, or (iii) on-sequencer enrichment.
10 . The method of claim 2 , wherein the sequencing comprises whole genome sequencing or targeted sequencing.
11 . The method of claim 10 , wherein the targeted sequencing comprises sequencing of introns, exons, intergenic regions, or a combination thereof.
12 . The method of claim 2 , wherein the subset of somatic variants comprises at least 10, at least 50, at least 100, at least 150, at least 200, at least 250, or at least 500 tumor-specific somatic mutations.
13 . The method of claim 12 , wherein the subset of somatic variants comprises one or more somatic mutations selected from SNVs, insertions, deletions, and translocations.
14 . The method of claim 2 further comprising determining a tumor fraction.
15 . (canceled)
16 . The method of claim 2 , wherein the tumor sample comprises a solid tumor biopsy or a fluid sample.
17 . The method of claim 16 , wherein the fluid sample is selected from blood, blood plasma, blood serum, urine, saliva, and cerebral spinal fluid (CSF).
18 . The method of claim 2 , wherein the non-tumor sample comprises a tissue sample matched to a tissue of origin of the tumor sample.
19 . (canceled)
20 . The method of claim 2 , wherein the patient has completed at least one cancer treatment prior to obtaining the tumor sample and the non-tumor sample.
21 . (canceled)
22 . The method of claim 2 further comprising repeating (f)-(i) with a second, third, fourth, fifth, sixth, seventh, eight, ninth, or tenth further sample of blood, plasma, or serum at successive time points.
23 . The method of claim 22 , wherein (f)-(i) are repeated one or more times while the patient is in remission or is undergoing treatment for the cancer.
24 . (canceled)
25 . The method of claim 22 , wherein (f)-(i) are repeated one or more times coinciding with or prior to surgery; following, during, or prior to administration of chemotherapy; following, during, or prior to radiation therapy; following, during, or prior to administration of an immunotherapy; following, during, or prior to administration of a cell therapy; or following, during, or prior to administration of a biologic therapy.
26 .- 29 . (canceled)
30 . The method of claim 2 , wherein the tumor is selected from adrenal cancer, anal cancer, bile duct cancer, bladder cancer, bone cancer, a brain/CNS tumor, breast cancer, Castleman disease, cervical cancer, colon or rectum cancer, endometrial cancer, esophagus cancer, a Ewing tumor, eye cancer, gallbladder cancer, a gastrointestinal carcinoid tumor, a gastrointestinal stromal tumor (GIST), gestational trophoblastic disease, Hodgkin disease, Kaposi sarcoma, kidney cancer, laryngeal and hypopharyngeal cancer, leukemia, liver cancer, lung cancer, lymphoma, malignant mesothelioma, multiple myeloma, myelodysplastic Syndrome, nasal cavity or paranasal sinus cancer, nasopharyngeal cancer, neuroblastoma, oral cavity or oropharyngeal cancer, osteosarcoma, ovarian cancer, pancreatic cancer, penile cancer, a pituitary tumor, prostate cancer, retinoblastoma, rhabdomyosarcoma, salivary gland cancer, skin cancer, small intestine cancer, stomach cancer, testicular cancer, thymus cancer, thyroid cancer, uterine sarcoma, vaginal cancer, vulvar cancer, Waldenstrom macroglobulinemia, and Wilms tumor.
31 . The method of claim 2 , wherein selecting a subset of somatic variants comprises subtracting an expected error rate from the expected variant allele frequency.
32 . The method of claim 33 , wherein the genomic data comprises DNA sequencing data, whole genome sequencing data, whole exome sequencing data, targeted genomic sequencing data, cfDNA sequencing data, chromatin immunoprecipitation sequencing data, reference genome data, transcriptomics data, epigenomics data, or proteomics data.
33 . A method of selecting tumor-specific somatic mutations for preparing a probe set for enriching circulating tumor DNA (ctDNA) from a sample, comprising:
sequencing DNA obtained from a tumor sample from a cancer patient and sequencing DNA obtained from a non-tumor sample from the cancer patient, thereby obtaining sequences of DNA from the tumor sample and sequences of DNA from the non-tumor sample;
determining a set of somatic variants based on differences between sequences of DNA from the tumor sample and sequences of DNA from the non-tumor sample; and
selecting a subset of tumor-specific somatic variants that are suitable for enriching ctDNA by:
(i) calculating, using a computer processor, an expected variant allele frequency based on copy number and allele balance of each of the somatic variants in the set of somatic variants, and selecting tumor-specific somatic variants for which the expected variant allele frequency is above a reference threshold,
(ii) determining, based on a plurality of features of the set of somatic variants, a subset of tumor-specific somatic variants, wherein the plurality of features are selected by a machine learning model trained with genomic data, or
(iii) a combination of (i) and (ii).