Combinatorial DNA screening
The present disclosure relates to methods for detecting unique genetic signatures derived from markers such as, for example, mutations, somatic or germ-line, in nucleic acids obtained from biological samples. The sensitivity of the methods provides for detection of mutations associated with a disease, e.g., cancer mutations, or with inherited disease, e.g., an autosomal recessive disease, in a noninvasive manner at ultra-low proportions of sequences carrying mutations to sequences carrying normal, e.g., non-cancer sequences, or a reference sequence, e.g., a human reference genome.
1. A method for preparing a deoxyribonucleic acid (DNA)-enriched fraction from a cancer patient, comprising:
(a) obtaining a tumor sample and a non-tumor sample from the cancer patient;
(b) sequencing genomic DNA from the tumor sample and sequencing genomic DNA from the non-tumor sample, thereby obtaining sequences of genomic DNA from the tumor sample and sequences of genomic DNA from the non-tumor sample;
(c) aligning the sequences of genomic DNA from the tumor sample to a reference human genome that is not from the patient thereby obtaining a set of tumor-specific mutations and further obtaining from the set of tumor-specific mutations a set of tumor-specific somatic mutation sequences that are present in the sequences of genomic DNA from the tumor sample but not present in the sequences of genomic DNA from the non-tumor sample;
(d) extracting cell-free DNA fragments (cfDNA) from a substantially cell-free fluid sample of blood plasma or blood serum obtained from the cancer patient;
(e) contacting the extracted cfDNA fragments 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 set of tumor-specific somatic mutation sequences; and
(f) enriching a fraction of DNA corresponding to the set of tumor-specific somatic mutation sequences from the extracted cfDNA fragments by:
(i) hybrid capture-based enrichment;
(ii) PCR-target enrichment; or
(iii) on-sequencer enrichment.
2. The method of claim 1 , wherein the method comprises a detection sensitivity of about 20 to about 50 ctDNA fragments comprising one or more of the set of somatic mutations in the fluid sample per a total background of about 500,000 cfDNA fragments.
3. The method of claim 1 , wherein the plurality of oligonucleotides is capable of detecting at least 10 different tumor-specific somatic mutations.
4. The method of claim 1 further comprising sequencing one or more of the DNA fragments.
5. The method of claim 1 , wherein extracting cfDNA fragments from the substantially cell-free fluid sample of blood plasma or blood serum comprises separating cfDNA from the blood plasma or blood serum sample.
6. The method of claim 1 , wherein the cancer patient has a cancer 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.
7. The method of claim 1 , wherein the plurality of oligonucleotides is capable of detecting at least 50 different tumor-specific somatic mutations.
8. The method of claim 1 , wherein the plurality of oligonucleotides is capable of detecting at least 500 different tumor-specific somatic mutations.
9. The method of claim 1 , wherein sequencing genomic DNA from the tumor sample of the patient and sequencing genomic DNA from the non-tumor sample of the patient comprises whole genome sequencing.
10. The method of claim 1 , wherein sequencing genomic DNA from the tumor sample of the patient and sequencing genomic DNA from the non-tumor sample of the patient comprises targeted sequencing.
11. The method of claim 10 , wherein the targeted sequencing comprises sequencing introns, exons, or a combination thereof.
12. The method of claim 1 , wherein (d)-(f) are repeated one or more times following completion of a cancer treatment.
13. The method of claim 1 , where wherein (d)-(f) are repeated one or more times while the cancer patient is in remission.
14. The method of claim 1 , where wherein (d)-(f) are repeated one or more times coinciding with or prior to surgery; following, during, or prior to administration of chemotherapy; or following, during, or prior to radiation therapy.