title: Digital PCR of Genomic Rearrangements for Monitoring Circulating Tumour DNA.
abstract: Identifying circulating tumour DNA (ctDNA) for monitoring of cancer therapy is dependent on the development of readily designed, sensitive cancer-specific DNA markers. Genomic rearrangements that are present in the vast majority of cancers provide such markers.Tumour DNA isolated from two fresh-frozen lung tumours underwent whole genome sequencing. Genomic rearrangements were detected using a new computational algorithm, GRIDSS. Four genomic rearrangements from each tumour were chosen for further study using rearrangement-specific primers. Six of the eight rearrangements tested were identified as tumour-specific, the remaining two were present in the germline. ctDNA was quantified using digital PCR for the tumour genomic rearrangements in patient blood. Interestingly, one of the patients had no detectable ctDNA either prior to or post surgery although the rearrangements were readily detectable in the tumour DNA.This study demonstrates the feasibility of using digital PCR based on genomic rearrangements for the monitoring of minimal residual disease. In addition, whole genome sequencing provided further information enabling therapeutic choices including the identification of a cryptic EGFR exon 19 deletion in one patient and the identification of a high somatic mutation load in the other patient. This approach can be used as a model for all cancers with rearranged genomes.
authors.affiliation: Translational Genomics and Epigenomics Laboratory, Olivia Newton-John Cancer Research Institute, Melbourne, VIC, 3084, Australia. hongdo.do@onjcri.org.au.|School of Cancer Medicine, La Trobe University, Bundoora, VIC, 3084, Australia. hongdo.do@onjcri.org.au.|Department of Pathology, University of Melbourne, Parkville, VIC, 3010, Australia. hongdo.do@onjcri.org.au.
authors.forename: Hongdo
authors.initials: H
authors.lastname: Do
authors.affiliation: Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.|Department of Medical Biology, University of Melbourne, Parkville, VIC, 3010, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Cameron
authors.affiliation: Translational Genomics and Epigenomics Laboratory, Olivia Newton-John Cancer Research Institute, Melbourne, VIC, 3084, Australia.|Department of Medicine, University of Melbourne, Heidelberg, VIC, 3084, Australia.
authors.forename: Ramyar
authors.initials: R
authors.lastname: Molania
authors.affiliation: Department of Medicine, University of Melbourne, Heidelberg, VIC, 3084, Australia.|Medical Oncology, Olivia Newton-John Cancer Research Institute, Austin Health, Heidelberg, VIC, 3084, Australia.
authors.forename: Bibhusal
authors.initials: B
authors.lastname: Thapa
authors.affiliation: Medical Oncology, Olivia Newton-John Cancer Research Institute, Austin Health, Heidelberg, VIC, 3084, Australia.
authors.forename: Gareth
authors.initials: G
authors.lastname: Rivalland
authors.affiliation: Medical Oncology, Olivia Newton-John Cancer Research Institute, Austin Health, Heidelberg, VIC, 3084, Australia.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Mitchell
authors.affiliation: Tumour Targeting Laboratory, Olivia Newton-John Cancer Research Institute, Melbourne, Australia.
authors.forename: Carmel
authors.initials: C
authors.lastname: Murone
authors.affiliation: School of Cancer Medicine, La Trobe University, Bundoora, VIC, 3084, Australia.|Medical Oncology, Olivia Newton-John Cancer Research Institute, Austin Health, Heidelberg, VIC, 3084, Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: John
authors.affiliation: Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.|Department of Medical Biology, University of Melbourne, Parkville, VIC, 3010, Australia.
authors.forename: Anthony
authors.initials: A
authors.lastname: Papenfuss
authors.affiliation: Translational Genomics and Epigenomics Laboratory, Olivia Newton-John Cancer Research Institute, Melbourne, VIC, 3084, Australia. alex.dobrovic@onjcri.org.au.|School of Cancer Medicine, La Trobe University, Bundoora, VIC, 3084, Australia. alex.dobrovic@onjcri.org.au.|Department of Pathology, University of Melbourne, Parkville, VIC, 3010, Australia. alex.dobrovic@onjcri.org.au.
authors.forename: Alexander
authors.initials: A
authors.lastname: Dobrovic
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood / Q000235:genetics; D004273:DNA, Neoplasm / Q000097:blood / Q000235:genetics*; D066246:ErbB Receptors / Q000235:genetics; D005240:Feasibility Studies; D015321:Gene Rearrangement; D015894:Genome, Human / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood / Q000175:diagnosis / Q000235:genetics*; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D017422:Sequence Analysis, DNA / Q000379:methods
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: Droplet digital PCR; Genomic rearrangement; Liquid biopsy; Lung cancer; Whole genome sequencing