Limit of detection. A and B: Selected sample-specific variants of single nucleotide variant (SNV) and insertion/deletion (indel) (A) and copy number variant (CNV) (B) at 30%, 20%, and 10% tumor content in two samples, respectively. A: Variant allele frequencies in two samples [frozen and formalin-fixed, paraffin-embedded (FFPE)] with original tumor content of 91% and 65%, respectively, are shown with decreasing tumor content. B: Copy number log2(tumor/normal; T/N) of one focal amplification (EGFR, FFPE sample) and three deletions [two whole arm (1p, 19q, frozen sample) and one focal deletion (CDKN2A, FFPE sample)]. Inset shows 19q and 1p CNV log2(T/N) values at 30% to 10% tumor content for better resolution.