Abstract 232: Fully automated comprehensive genomic profiling for detection of cancer variants, gene fusions, and complex oncology endpoints
Authors: Lowman Geoffrey Marc , Cyanam Dinesh , Norris Emily , Toro Michelle , Nemes Coleen , Puranik Tanaya , Zhu Yan , Phan Alex , Wong Derek , Bernado Portia , Kralcheva Anelia , Nallandhighal Srinivas , Pickle Loni , Bigley April , Gupta Mohit , Jin Ying , El-Difrawy Sameh , Marcovitz Amir , Zare Fatima , Scafe Charles , Tseng Yu-Ting , Guo Jianjun , Mittal Vinay , Myrand Scott , Bandla Santhoshi , Williams Paul , Ingerman Eugene , Wong-Ho Elaine , Sadis Seth , Andersen Mark , Bennett Rob 
Published: April 2023

Introduction: We present the comprehensive genomic profiling performance of the Ion Torrent Genexus system using the Oncomine Comprehensive Assay Plus (OCA Plus), a 500+ gene targeted AmpliSeq-based oncology research panel that evaluates DNA variants (including copy number alterations), RNA fusions, and key oncology research endpoints including tumor mutational burden (TMB), microsatellite instability (MSI), and homologous recombination repair deficiency (HRD) via characterization of genomic instability by the newly introduced Genomic Instability Metric (GIM).

Methods: The Ion Torrent Genexus System provides comprehensive genomic profiling via automated sample-to-report workflow with next day results. The Genexus System supports oncology research panels such as OCA Plus, which is comprised of over 13,000 amplicons, and enables low input requirements of just 20ng of FFPE DNA and RNA. This study utilized cell lines, reference controls, and orthogonally tested FFPE research samples to evaluate detection of DNA variants, copy number alterations, RNA fusions, and key research endpoints, including MSI, TMB, and HRD. The OCA Plus panel was also evaluated for the ability to detect arm-level copy number changes in orthogonally validated FFPE samples.

Results: Commercial reference controls and FFPE research samples were sequenced using OCA Plus on the Genexus System to an average depth of ≥24 million reads per sample, with four DNA and RNA samples supported per run. SNV and MNV calling performance was assessed using the AcroMetrix Oncology Hotspot Control which has 377 variants covered by OCA Plus and delivered SNV sensitivity and PPV &gt;99% and MNV sensitivity of &gt;99% and PPV &gt;95%. MSI status was assessed using orthogonally tested FFPE samples from various tumor tissues (stomach, endometrial, colorectal) and returned status concordance of 99.4% with sensitivity and PPV &gt;99%. The TMB endpoint was tested using commercial controls and FFPE samples with a correlation of r2 &gt; 0.90 to orthogonal measurements. RNA Fusion reference controls showed 100% positive correlation. Copy number gain detection shows sensitivity of 99% and PPV &gt;95%, while homologous copy loss gives 100% PPV and sensitivity of &gt;90%. We also demonstrate high concordance to orthogonal methods in detection of HER2 amplifications, and the ability to detect arm-level copy number alterations such as 1p/19q co-deletions in IDH1 positive glioma samples.

Conclusion: The Genexus System combines minimal touch points and a rapid turnaround time to enable comprehensive genomic profiling for research assays such as OCA Plus for detection of rare variants and low-level fusion transcripts. Further, by providing accurate characterization of key oncology research endpoints, the Genexus System can accelerate research in oncology. For research use only. Not for use in diagnostic procedures.

Citation Format: Geoffrey Marc Lowman, Dinesh Cyanam, Emily Norris, Michelle Toro, Coleen Nemes, Tanaya Puranik, Yan Zhu, Alex Phan, Derek Wong, Portia Bernado, Anelia Kralcheva, Srinivas Nallandhighal, Loni Pickle, April Bigley, Mohit Gupta, Ying Jin, Sameh El-Difrawy, Amir Marcovitz, Fatima Zare, Charles Scafe, Yu-Ting Tseng, Jianjun Guo, Vinay Mittal, Scott Myrand, Santhoshi Bandla, Paul Williams, Eugene Ingerman, Elaine Wong-Ho, Seth Sadis, Mark Andersen, Rob Bennett. Fully automated comprehensive genomic profiling for detection of cancer variants, gene fusions, and complex oncology endpoints [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 232.