Examination of Plasma Cell-Free DNA of Glioma Patients by Whole Exome Sequencing

Abstract

Objectives: To analyze the plasma cell-free DNA (Cf-DNA) in glioma patients with high throughout sequencing for a novel non-invasive method for the early diagnosis and management of glioma.

Methods: Six patients with glioma were recruited from the Affiliated Hospital of Nantong University from June 2015 to September 2016. Their plasma samples were tested for Cf-DNA by whole exon sequencing and mutations were analyzed by bioinformatics.

Results: After filtering the raw sequencing data of Cf-DNA, 33,173 mutations were obtained from 12,462 genes of which 442 genes and 655 mutation sites were identical to that in the Catalogue of Somatic Mutations in Cancer database. However, when we compared the Cf-DNA data with the glioma mutated loci in the Cancer Genome Alta database, only 4 mutations matched with the glioma sequences in the Cancer Genome Alta and did not correspond to that of the paired-tumor tissues.

Conclusions: There were some cancer-related somatic mutations in the Cf-DNA of glioma patients, but no identical mutations were found in the paired solid tumors. Therefore, plasma Cf-DNA mutations may not be a suitable marker for the detection of glioma.

Keywords: Cell-free DNA; Glioma; Liquid biopsy; Whole exome sequencing.