A patient’s surgically resected tumor or biopsy sample undergoes whole-exome sequencing (WES) to identify tumor-specific variants.
A group of up to 48 variants are then selected using optimized algorithms. An assay targeting these mutations is customized to generate a personalized RaDaR panel.
Using the InVision® platform and the personalized assay, partition-based multiplex PCR (polymerase chain reaction) is performed. This generates sequencing libraries from the patient’s plasma cell-free DNA (cfDNA), tumor DNA and leukocyte DNA for the targeted regions.
The patient’s plasma cfDNA and leukocyte DNA (from blood buffy coat) are now sequenced at a high depth. Tumor DNA is also sequenced to confirm the variants are tumor-specific. Leukocyte DNA high-depth sequencing allows for the identification and removal of germline changes and confounding signals derived from clonal hematopoiesis of indeterminate potential (CHIP) (which may be present in the blood at low levels) from the analysis. This final process reduces false-positive results and contributes to high specificity and a high positive predictive value (PPV).
NGS data are analyzed by combining results across all tumor-specific variants to determine the patient’s MRD status. A report is then generated indicating whether tumor DNA was “Detected” or “Not Detected” in the patient’s blood samples.
