In a study published in PLOS One in April 2018, Ionescu-Zanetti and his colleagues compared the abilities of ERASE-Seq and those of current molecular barcoding methods. Using spiked human DNA mixed with clinically realistic DNA input quantities, the researchers sought to detect single nucleotide variants and indels between 0.05 percent and 1 percent allele frequency. They found that the tool could detect variants with greater than 90 percent sensitivity and a false positive rate below 0.1 calls per 10,000 possible variants. Jensen explained that Fluxion previously looked at other mutation caller techniques to integrate with its IsoFlux CTC isolation kits and Spotlight liquid biopsy panels, but the firm found their performance "unacceptable." He argued that the lack of high-quality callers led the group to develop and eventually release Erase-Seq in 2018, which is more of a statistical approach to identifying the true positives in a sample.
According to Jensen, Fluxion can validate a lab's panel using the Erase-Seq variant caller approach. The validation involves running a set of reference healthy samples through the firm's algorithm to develop a background model. Afterwards, the researchers run a few analytical samples to adjust the sequencing parameters, such as the depth of coverage. As part of the ongoing study, Cleveland Clinic assistant professor of radiation oncology Omar Mian and his colleagues are applying Erase-Seq to track tumor growth in a group of 30 hepatocellular cancer patients. The team is attempting to see whether the circulating tumor burden of disease and the amount of ctDNA changes before, during, or after ablative therapies (such as stereotactic radiation), surgical management like mastectomy, or tumor removal.
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