Characterization of Synthetic Reference Material for ctDNA Detection Assays

Abstract

Precision medicine is a fast-growing field within the cancer biotechnology industry that tailors a patient’s treatment to their specific biological makeup. Liquid biopsy offers a noninvasive, more heterogenous look into a patient’s cancer compared to solid tissue biopsies. Liquid biopsy circulating tumor DNA (ctDNA) detection assays allow each patient’s treatment to be informed by their individual cancer mutational status. The development and validation of these diagnostic tests are essential for them to be a clinically relevant tool - a tool that doctors and patients can use. Validation provides analytical accuracy and is what is used to build a case for clinical utility. A key part to validating a diagnostic test is to have a reliable reference material to which you can assess the diagnostic test against. Finding or making the correct reference material is difficult, and there are particular hurdles to overcome when designing a biologically similar reference material for ctDNA. There are preanalytical variables that can affect ctDNA measurements, from the way the DNA is fragmented to the background DNA that is incorporated and to the matrix it is suspended in. This thesis evaluates off-the-shelf reference materials for their suitability to be used for ctDNA assay validation. Reference material from 3 different vendors; Anchor Molecular, Horizon, and SeraCare, are evaluated. Each vendor is assessed on accuracy, precision, and ctDNA concordance. Overall Seracare has the best performance, next is Anchor Molecular and then Horizon. Choosing the correct reference material is imperative to validating a ctDNA detection assay and comparisons like these can aid in such imperative choices.