Skip Navigation
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

National Institute of Environmental Health Sciences

Use this QR code to view the newest version of this document
Use this QR code to view the newest version of this document

Your Environment. Your Health.

Publication Detail

Title: Longitudinal Relationship between Idylla Plasma ctBRAF V600 Mutation Detection and Tumor Burden in Patients with Metastatic Melanoma.

Authors: Linder, Mark William; Egger, Michael E; Van Meter, Tracy; Rai, Shesh N; Valdes Jr, Roland; Hall, Melissa Barousse; Wu, Xiaoyong; Alghamdi, Norah; Chesney, Jason A

Published In Mol Diagn Ther, (2021 05)

Abstract: BACKGROUND: Circulating tumor DNA (ctDNA) may complement radiography for interim assessment of patients with cancer. OBJECTIVE: Our objective was to explore the relationship between changes in plasma ctDNA versus radiographic imaging among patients with metastatic melanoma. METHODS: Using the Idylla system, we measured B-Raf proto-oncogene (BRAF) V600 ctDNA in plasma from 15 patients with BRAF V600E/K-positive primary tumors undergoing standard-of-care monitoring, including cross-sectional computed tomography (CT) imaging. BRAF V600 mutant allele frequency (%MAF) was calculated from the Idylla Cq values and directly measured using droplet digital polymerase chain reaction (ddPCR). RESULTS: The Idylla ctDNA assay demonstrated 91% sensitivity, 96% specificity, 91% positive predictive value, and 96% negative predictive value for the presence of > 93 mm metastatic disease. Qualitative ctDNA results corresponded to changes in RECIST (Response Evaluation Criteria in Solid Tumors) 1.1 status determined by CT imaging in 11 of 15 subjects (73%). Calculated %MAF results correlated with ddPCR (R2 = 0.94) and provided evidence of progressive disease 55 and 97 days in advance of CT imaging for two subjects with persistently positive qualitative results. CONCLUSIONS: Overall, interim ctDNA results provided evidence of partial response or progressive disease an average of 82 days before radiography. This pilot study supports the feasibility of using the Idylla plasma BRAF V600 ctDNA assay as a complement to CT scanning for routine monitoring of therapeutic response. Somatic mutation quantification based on Cq values shows promise for identifying disease progression and warrants further validation.

PubMed ID: 33970440 Exiting the NIEHS site

MeSH Terms: Circulating Tumor DNA/genetics; Cross-Sectional Studies; Feasibility Studies; Humans; Longitudinal Studies; Male; Melanoma/blood; Melanoma/diagnostic imaging*; Melanoma/genetics; Melanoma/pathology*; Mutation*; Neoplasm Metastasis; Pilot Projects; Proto-Oncogene Proteins B-raf/blood*; Proto-Oncogene Proteins B-raf/genetics; Sensitivity and Specificity; Standard of Care; Tomography, X-Ray Computed; Tumor Burden

Back
to Top