How are Horizon cfDNA Reference Standards different from other circulating tumor DNA controls?

In molecular biology, plasmid DNA has proved to be a vital tool for many applications. However, when developing or validating circulating tumor DNA assays (also known as ctDNA assays) which will ultimately measure fragmented human genomic DNA samples, plasmid and synthetic DNA are not ideal control samples. Laboratories should be cautious in adopting plasmids as controls for such assays, as plasmids do not represent the true genomic complexity of human tumor samples. Therefore, the results achieved with controls derived from plasmids may not be robust. By contrast, Horizon cfDNA and ctDNA Reference Standards are made with genomic DNA extracted from engineered cell lines, which is fragmented to mimic circulating tumor DNA in clinical samples.