Johns Hopkins University

Isaac A Kinde

Bert Vogelstein

Kenneth W Kinzler

Nickolas Papadopoulos

Luis Diaz

Ralph Hruban

George J Netto

Chetan Bettegowda

Yuxuan Wang

The identification of mutations that are present in a small fraction of DNA templates is essential for progress in several areas of biomedical research. Though massively parallel sequencing instruments are in principle well-suited to this task, the error rates in such instruments are generally too high to allow confident identification of rare variants. We here describe an approach that can substantially increase the sensitivity of massively parallel sequencing instruments for this purpose. One example of this approach, called 'Safe-SeqS' for (Safe-Sequencing System) includes (i) assignment of a unique identifier (UID) to each template molecule; (ii) amplification of each uniquely tagged template molecule to create UID-families; and (iii) redundant sequencing of the amplification products. PCR fragments with the same UID are truly mutant (“super-mutants”) if ≥95% of them contain the identical mutation. We illustrate the utility of this approach for determining the fidelity of a polymerase, the accuracy of oligonucleotides synthesized in vitro, and the prevalence of mutations in the nuclear and mitochondrial genomes of normal cells.

Safe sequencing system

Massively parallel sequencing of cell-free, maternal plasma DNA was recently demonstrated to be a safe and effective screening method for fetal chromosomal aneuploidies. Here, we report an improved sequencing method achieving significantly increased throughput and decreased cost by replacing laborious sequencing library preparation steps with PCR employing a single primer pair. Using this approach, samples containing as little as 4% trisomy 21 DNA could be readily distinguished from euploid samples.

Rapid aneuploidy detection

The identification of mutations that are present in a small fraction of DNA templates is essential for progress in several areas of biomedical research. Though massively parallel sequencing instruments are in principle well-suited to this task, the error rates in such instruments are generally too high to allow confident identification of rare variants. We here describe an approach that can substantially increase the sensitivity of massively parallel sequencing instruments for this purpose. One example of this approach, called 'Safe-SeqS' for (Safe-Sequencing System) includes (i) assignment of a unique identifier (UID) to each template molecule; (ii) amplification of each uniquely tagged template molecule to create UID-families; and (iii) redundant sequencing of the amplification products. PCR fragments with the same UID are truly mutant ('super-mutants') if &#x2265;95% of them contain the identical mutation. We illustrate the utility of this approach for determining the fidelity of a polymerase, the accuracy of oligonucleotides synthesized in vitro, and the prevalence of mutations in the nuclear and mitochondrial genomes of normal cells.

TERT promoter mutations occur in both papillary and flat lesion bladder cancers, are the most frequent genetic alterations identified to date in noninvasive precursor lesions of the bladder, are detectable in urine, and appear to be strongly associated with bladder cancer recurrence. The TERT promoter mutations are useful urinary biomarker for both the early detection and monitoring of bladder neoplasia.

TERT promoter mutations in urothelial neoplasia

The recently developed liquid-based Papanicolaou (Pap) smear allows not only cytologic evaluation but also collection of DNA for detection of HPV, the causative agent of cervical cancer. We tested these samples to detect somatic mutations present in rare tumor cells that might accumulate in the cervix once shed from endometrial and ovarian cancers. A panel of commonly mutated genes in endometrial and ovarian cancers was assembled and used to identify mutations in all 46 endometrial or cervical cancer tissue samples. We were able also able to identify the same mutations in the DNA from liquid Pap smears in 100% of endometrial cancers (24 of 24) and in 41% of ovarian cancers (9 of 22). We developed a sequence-based method to query mutations in 12 genes in a single liquid Pap smear without prior knowledge of the tumor's genotype.

Papanicolaou test for ovarian and endometrial cancers

Though massively parallel sequencing instruments are in principle well-suited to the task of identification of mutations present in a small fraction of DNA templates, the error rates in such instruments are generally too high to allow confident identification of rare variants. An approach that can substantially increase the sensitivity of massively parallel sequencing instruments for this purpose is called 'Safe-SeqS' for (Safe-Sequencing System) and includes (i) assignment of a unique identifier (UID) to each template molecule; (ii) amplification of each uniquely tagged template molecule to create UID-families; and (iii) redundant sequencing of the amplification products. PCR fragments with the same UID are truly mutant ('super-mutants') if &#x2265;95% of them contain the identical mutation.

The present disclosure relates to methods for testing a human for aneuploidy. In some aspects, a plurality of chromosomal sequences in a DNA sample from a human are amplified with a single pair of primers complementary to said chromosomal sequences to form a plurality of amplicons, wherein the plurality of amplicons are not identical, and wherein the plurality of amplicons include sequences on a query chromosome and sequences on a plurality of reference chromosomes. In some aspects, reactions are performed to determine the nucleotide sequence of at least 3 nucleotides of the plurality of amplicons. In some aspects, amplicon nucleotide sequences are matched in silico to genomic sequences at genomic loci. In some aspects, numbers of matching amplicons at individual genomic loci are counted. In some aspects, numbers of amplicons matched to genomic loci on the query chromosome are compared to numbers of amplicons matched to genomic loci on the reference chromosomes.

Error rates in massively parallel sequencing instruments are generally too high to allow confident identification of rare variants. An approach that can substantially increase the sensitivity of massively parallel sequencing instruments for this purpose, called 'Safe-SeqS' for (Safe-Sequencing System) includes (i) assignment of a unique identifier (UID) to each template molecule; (ii) amplification of each uniquely tagged template molecule to create UID-families; and (iii) redundant sequencing of the amplification products. PCR fragments with the same UID are truly mutant ('super-mutants') if &#x2267;95% of them contain the identical mutation. We illustrate the utility of this approach for determining the fidelity of a polymerase, the accuracy of oligonucleotides synthesized in vitro, and the prevalence of mutations in the nuclear and mitochondrial genomes of normal cells.

The identification of mutations that are present in a small fraction of DNA templates is essential for progress in several areas of biomedical research. Though massively parallel sequencing instruments are in principle well-suited to this task, the error rates in such instruments are generally too high to allow confident identification of rare variants. We here describe an approach that can substantially increase the sensitivity of massively parallel sequencing instruments for this purpose. One example of this approach, called 'Safe-SeqS' for (Safe-Sequencing System) includes (i) assignment of a unique identifier (UID) to each template molecule; (ii) amplification of each uniquely tagged template molecule to create UID-families; and (iii) redundant sequencing of the amplification products. PCR fragments with the same UID are truly mutant ('super-mutants') if &#x2267;95% of them contain the identical mutation. We illustrate the utility of this approach for determining the fidelity of a polymerase, the accuracy of oligonucleotides synthesized in vitro, and the prevalence of mutations in the nuclear and mitochondrial genomes of normal cells.

Growing community of inventors

Beaumont, CA, United States of America

Isaac A Kinde