title: Monitoring response to therapy in melanoma by quantifying circulating tumour DNA with droplet digital PCR for BRAF and NRAS mutations.
abstract: We assessed the utility of droplet digital PCR (ddPCR) to evaluate the potential of using circulating tumour DNA (ctDNA) as a post therapy monitoring tool in melanoma by comparing it to serum LDH levels and RECIST scores. ddPCR was shown to be reliable in distinguishing mutant from wild type alleles with no false positives. Subsequently, we quantified ctDNA ((V600E)BRAF,(V600K)BRAF or (Q61H)NRAS) in 6 stage IV melanoma patients across several time points during their treatment course. All tested patients had detectable ctDNA, which exhibited dynamic changes corresponding to the changes in their disease status. The ctDNA levels fell upon treatment response and rose with detectable disease progression. In our group of patients, ctDNA was more consistent and informative than LDH as a blood-based biomarker. In addition, BRAF mutant ctDNA as detected by ddPCR could be used diagnostically where the tumour block was unavailable. In conclusion, this study demonstrates the applicability of using ddPCR to detect and quantify ctDNA in the plasma of melanoma patients.
authors.affiliation: 1] Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia [2] Department of Surgery, University of Melbourne, Austin Health. Heidelberg, Victoria, Australia.
authors.forename: Simon Chang-Hao
authors.initials: SC
authors.lastname: Tsao
authors.affiliation: Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Weiss
authors.affiliation: 1] Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia [2] School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Hudson
authors.affiliation: Department of Surgery, University of Melbourne, Austin Health. Heidelberg, Victoria, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Christophi
authors.affiliation: 1] Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia [2] Department of Pathology, University of Melbourne, Parkville, Victoria, Australia [3] School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cebon
authors.affiliation: 1] Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia [2] Department of Pathology, University of Melbourne, Parkville, Victoria, Australia [3] School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia.
authors.forename: Andreas
authors.initials: A
authors.lastname: Behren
authors.affiliation: 1] Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia [2] Department of Pathology, University of Melbourne, Parkville, Victoria, Australia [3] School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Dobrovic
mesh_terms: D045744:Cell Line, Tumor; D004273:DNA, Neoplasm / Q000097:blood / Q000235:genetics*; D005260:Female; D011905:Genes, ras; D006801:Humans; D045022:Lactate Dehydrogenases / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D008545:Melanoma / Q000097:blood / Q000175:diagnosis / Q000235:genetics* / Q000628:therapy; D009154:Mutation; D009362:Neoplasm Metastasis; D016133:Polymerase Chain Reaction; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D004273:DNA, Neoplasm; D045022:Lactate Dehydrogenases; D048493:Proto-Oncogene Proteins B-raf