Abstract 3108: Combined cfDNA and cfRNA NGS testing for cancer patient care

Background: NGS based liquid biopsy has its unique advantage in cancer patient care/monitoring as it allows repeated testing of a spectrum of target sites at multiple time points. However, cfDNA assays usually can only cover focused genomic regions. In order to monitor dynamic fusion and alternative splicing variants, we developed and validated a cfRNA assay which can be used in combination with cfDNA assays to get clear snapshots of mutation landscapes in cancer patients. Here we introduce our application of the combined cfDNA and cfRNA approach to cancer patient care. Method: A single tube of blood is taken from cancer patients, which is used to extract both cfDNA and cfRNA. Predicine proprietary cfDNA and cfRNA NGS assays and analysis pipelines are used to detect SNV/INDEL, CNV as well as fusion and alternative RNA splicing variants from cancer samples, collected at multiple time points from patients during or after treatment. Results: The cfDNA+cfRNA combined approach allows the cross-validation of results from both methods, which greatly elevated the confidence level of our testing results. For example, a case in which EML4-ALK fusion was detected at cfDNA level but only with fairly low allele frequency was confidently confirmed, as EML4-ALK fusion was also detected at cfRNA level. On the other hand, the cfDNA+cfRNA combined approach allows us to study the broad mutation landscape from both cfDNA and cfRNA levels. For example, for a cohort of prostate samples, the changes of AR alternative splicing forms and the cfDNA mutation landscape can be observed from the same tube of blood samples. In general, the cfDNA+cfRNA combined approach provides a more complete molecular biomarker profiles and extract more information that can be used to instruct cancer patient care. Citation Format: Yong Huang, Yue Zhang, Binggang Xiang, Zhixin Zhao, Xiaohong Wang, Feng Xie, Reza Moktari, Kemin Zhou, Pan Du, Shidong Jia, Jianjun Yu. Combined cfDNA and cfRNA NGS testing for cancer patient care [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3108.