Abstract LB-246: Detection of circulating tumor DNA in early stage cancers

Abstract

Early detection is a major goal for reducing mortality of human cancer. However, non-invasive detection of early stage tumors has remained a challenge. We have developed an approach called Targeted Error Correction Sequencing (TEC-Seq) for ultra-sensitive analyses of circulating cell-free tumor DNA (ctDNA). This methodology involves in-solution targeted capture of multiple regions of the genome and deep sequencing (~30,000x) of cell-free DNA fragments. Laboratory and bioinformatic methods were optimized to enrich for rare ctDNA molecules and to reduce potential amplification, sequencing, and contamination errors. We have used this approach to examine 58 cancer related genes, and demonstrated a limit of detection of mutant to wild-type DNA of 0.05% and a specificity >99.999% across targeted regions of interest. We applied this method to analyze plasma from healthy individuals as well as over 200 individuals with breast, lung, colorectal and ovarian cancers. Analysis of plasma from 44 healthy individuals revealed no tumor-related somatic mutations and identified alterations in genes related to myelodysplasia in a subset of cases. Among patients with cancer, we detected measurable ctDNA in 56%, 71%, 57%, and 56% of patients with early stage (I and II) breast, colorectal, lung and ovarian cancer. Over three quarters of patients with late stage (III and IV) disease had detectable ctDNA among all cases analyzed. Analyses of mutations in the circulation revealed a high concordance with alterations in the independently analyzed tumors of these patients. These analyses provide a widely applicable, ultra-sensitive, and non-invasive method for detection of ctDNA, and have important implications for detection of early stage disease and management of patients with cancer. Citation Format: Jillian A. Phallen, Mark Sausen, Vilmos Adleff, Alessandro Leal, Jacob Fiksel, Carolyn Hruban, Savannah Speir, Eniko Papp, Valsamo Anagnostou, Mai-Britt W. Orntoft, Thomas Reinert, Brian D. Woodward, Derek Murphy, Sonya Parpart-Li, David Riley, Monica Nesselbush, Naomi Sengamalay, Andrew Georgiadis, Rob Scharpf, Qing K. Li, Sian Jones, Samuel Angiuoli, Joost Huiskens, Cornelis Punt, Nicole van Grieken, Remond Fijneman, Gerrit Meijer, Hatim Husain, Luis Diaz, Torben Ørntoft, Hans J. Nielsen, Claus L. Anderson, Victor E. Velculescu. Detection of circulating tumor DNA in early stage cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-246. doi:10.1158/1538-7445.AM2017-LB-246