Development of a breast and lung cancer research panel to target therapeutically relevant copy number and gene fusion variants from blood.

Abstract

e12518 Background: With recent advances in next-generation sequencing (NGS) technologies, it is now possible to detect somatic mutations with allele frequencies in blood samples as low as 0.1% from circulating tumor DNA. A natural extension to this achievement is adding the ability to simultaneously detect copy number variants and gene fusions. A panel such as this addresses a full repertoire of variant classes found to be linked with certain tumors and would enable researchers additional tools to profile cancer samples more dynamically thus enriching current diagnostic tool sets. Here, we present progress on such an approach and apply current NGS technology to achieve our goals. Methods: Samples were sequecned using the Ion S5™ system. Results: Using control samples, we can reproducibly demonstrate detection of ERBB2 (HER2/neu) gene amplifications with high statistical significance and as low as a 2 fold difference versus non-amplified loci in titration experiments. In addition, this ERBB2 gene amplification was detected in the context of a validated breast cancer somatic mutation panel in which no negative impact was exhibited and mutation detection specificity and sensitivity were both greater than 90%. Lastly, we developed an additional panel to detect gene fusions relevant to lung cancer. Using the titration approach above, the EML4-ALK fusion variant was shown to have a limit of detection near 1% with no negative impact on detection sensitivity and specificity when combined with the validated lung cfDNA somatic mutation panel. Conclusions: From the outcomes of these experiments, we have shown the ability to reproducibly and simultaneously detect copy number and gene fusion variants as well as somatic mutations at very low limits of detection in a cell free DNA background derived from blood samples.