Identifying somatic variants within a tumor sample can be accomplished by performing whole-genome sequencing (WGS) of DNA extracted from a cancer sample and DNA from a matching normal sample. Cancer-specific variants are those observed in the tumor sample but absent from the normal sample. The ability of this approach to detect somatic variants depends, in part, upon the variant frequency within the tumor sample as well as the total sequence depth. The purity and heterogeneity of the tumor sample
strongly impact the allele frequencies of the somatic mutations present and thus also impact the ability to detect these variants.
This white paper quantitates the ability to detect somatic variants in samples of variable purity at various sequencing depths using a HiSeq(r) System and the Illumina tumor/normal data analysis workflow.
