Abstract A10: Glioma cell-free DNA methylation marker for diagnosis and monitoring

e14537 Background: Nasopharyngeal carcinoma (NPC) is one of the most prevalent malignancies among populations native to Southeast Asia, the Mediterranean Basin and the Arctic. Early diagnosis of NPC is predicted to improve survival. The identification of cancer-specific DNA methylation patterns of cell-free DNA (cfDNA) isolated from blood samples is an established approach for detecting various cancers. In the present study, we evaluated the performance characteristics of a previously identified NPC methylation marker panel for the diagnosis of nasopharyngeal carcinoma. Methods: Retrospective samples were obtained for 168 subjects, including: 59 subjects diagnosed with NPC (Stage I to IV), 14 subjects diagnosed with benign nasopharyngeal disease and 43 healthy subjects. In addition, sample were obtained for 52 subjects diagnosed with breast, colorectal, liver or lung cancer. Samples were provided to the laboratory blinded for DNA methylation analysis by using the IvyGene Platform. Results: A total of 57 of the 59 samples drawn from subjects with NPC were correctly identified for an overall sensitivity of 97%, with little difference between the sensitivity of detecting Stage I to Stage IV nasopharyngeal carcinoma (range 92% to 100%). For subjects diagnosed with other cancers, 85% of colorectal cancer samples, 82% of lung cancer samples, 93% of both breast cancer and liver cancer samples, were correctly identified as negative for NPC, for a total calculated analytical specificity of 86%. Additionally, all 43 samples drawn from healthy donors and 14 samples drawn from subjects diagnosed with benign nasopharyngeal disease were correctly identified as negative for nasopharyngeal carcinoma for a combined specificity of 100%. Conclusions: The NPC methylation panel was demonstrated to be both sensitive and specific for the detection of nasopharyngeal carcinoma. The potential of cfDNA methylation markers for the early detection of nasopharyngeal carcinoma is predicted to improve patient outcomes through earlier detection of the disease.

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Aging-associated distinctive DNA methylation changes of LINE-1 retrotransposons in pure cell-free DNA from human blood

Scientific Reports ◽

10.1038/s41598-020-79126-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Wardah Mahmood ◽

Lars Erichsen ◽

Pauline Ott ◽

Wolfgang A. Schulz ◽

Johannes C. Fischer ◽

...

Keyword(s):

Dna Methylation ◽

Cell Free Dna ◽

The Past ◽

Free Dna ◽

Genome Wide ◽

Cancerous Cell ◽

Pure Cell ◽

Epigenetic Biomarker ◽

Methylation Patterns ◽

Cancerous Cells

AbstractLINE-1 hypomethylation of cell-free DNA has been described as an epigenetic biomarker of human aging. However, in the past, insufficient differentiation between cellular and cell-free DNA may have confounded analyses of genome-wide methylation levels in aging cells. Here we present a new methodological strategy to properly and unambiguously extract DNA methylation patterns of repetitive, as well as single genetic loci from pure cell-free DNA from peripheral blood. Since this nucleic acid fraction originates mainly in apoptotic, senescent and cancerous cells, this approach allows efficient analysis of aged and cancerous cell-specific DNA methylation patterns for diagnostic and prognostic purposes. Using this methodology, we observe a significant age-associated erosion of LINE-1 methylation in cfDNA suggesting that the threshold of hypomethylation sufficient for relevant LINE-1 activation and consequential harmful retrotransposition might be reached at higher age. We speculate that this process might contribute to making aging the main risk factor for many cancers.

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