Clinical validation of Whole Genome Sequencing for cancer diagnostics

Abstract

Whole genome sequencing (WGS) using fresh frozen tissue and matched blood samples from cancer patients is becoming in reach as the most complete genetic tumor test. With a trend towards the availability of small biopsies and the need to screen an increasing number of (complex) biomarkers, the use of a single all-inclusive test is preferred over multiple consecutive assays. To meet high-quality diagnostics standards, we optimized and clinically validated WGS sample and data processing procedures resulting in a technical success rate of 95.6% for fresh-frozen samples with sufficient ([≥]20%) tumor content. Independent validation of identified biomarkers against commonly used diagnostic assays showed a high sensitivity (recall) (98.5%) and precision (positive predictive value) (97.8%) for detection of somatic SNV and indels (across 22 genes), and high concordance for detection of gene amplification (97.0%, EGRF and MET) as well as somatic complete loss (100%, CDKN2A/p16). Gene fusion analysis showed a concordance of 91.3% between DNA-based WGS and an orthogonal RNA-based gene fusion assay. Microsatellite (in)stability assessment showed a sensitivity of 100% with a precision of 94%, and virus detection (HPV) an accuracy of 100% compared to standard testing. In conclusion, whole genome sequencing has a >95% sensitivity and precision compared to routinely used DNA techniques in diagnostics and all relevant mutation types can be detected reliably in a single assay.