Tempus Labs, Inc.

Wei Zhu

Robert Tell

Terri M Driessen

Christine Lo

Justin David Finkle

Methods, systems, and software are provided for validating a somatic sequence variant in a subject having a cancer condition. Sequence reads are obtained from sequencing cell-free DNA fragments in a liquid biopsy sample of the subject. Sequence reads are aligned to a reference sequence. A variant allele fragment count and locus fragment count are identified for a candidate variant that maps to a locus in the reference sequence. The variant allele fragment count is compared against a dynamic variant count threshold for the locus. The threshold is based on a pre-test odds of a positive variant call for the locus, based on the prevalence of variants in a genomic region including the locus in a cohort of subjects having the cancer condition. The somatic sequence variant in the subject is validated, or rejected, when the variant allele fragment count for the candidate variant satisfies, or does not satisfy, the threshold.

Methods and systems for dynamic variant thresholding in a liquid biopsy assay

Methods, systems, and software are provided for estimating a circulating tumor fraction for a test subject. Sequence reads are obtained from a panel-enriched sequencing reaction, including sequences for a first plurality of cfDNA fragments corresponding to probe sequences and a second plurality of cfDNA fragments not corresponding to probe sequences. Bin-level coverage ratios are determined from the sequences. Segments are formed by grouping adjacent bins based on similar coverage ratios and segment-level coverage ratios are determined based on bin-level coverage ratios for bins in the segment. For each simulated circulating tumor fraction in a plurality of circulating tumor fractions, segments are fitted to an integer copy state by identifying the integer copy state that best matches the segment-level coverage ratio. The circulating tumor fraction for the test subject is determined using error optimization between segment-level coverage ratios and integer copy states across the simulated circulated tumor fractions.

Estimation of circulating tumor fraction using off-target reads of targeted-panel sequencing

Methods, systems, and software are provided for validating a copy number variation in a test subject. A first dataset is obtained comprising bin-level sequence ratios, segment-level sequence ratios and segment-level measures of dispersion. Bins representing regions of a human reference genome are determined from sequencing cell-free nucleic acids in a liquid biopsy sample and reference samples. Segments encompass subsets of adjacent bins, where segment-level sequence ratios and measures of dispersion are determined using bin-level sequence ratios. A copy number status annotation for a segment is validated by applying the first dataset to a plurality of filters comprising a measure of central tendency bin-level sequence ratio filter, a confidence filter, and a measure of central tendency-plus-deviation bin-level sequence ratio filter. When a filter is fired, the copy number status annotation of the segment is rejected; and when no filter is fired, the copy number status annotation of the segment is validated.

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Naperville, IL, United States of America

Wei Zhu