GCparagon: Evaluation and correction of GC biases in cell-free DNA at the fragment level

We present GCparagon, a two-stage algorithm for computing and correcting GC biases in cell-free DNA (cfDNA) samples. The length of the highly fragmented cfDNAs and the number of GC bases are essential parameters in the calculations. Regions of low mappability, known reference genome assembly errors and regions surrounding assembly gaps are excluded from the bias computation. GCparagon outputs a bias matrix and an optional tagged BAM file with GC bias balance weights as alignment tags. Parallelization allows calculation of a GC bias estimate in less than 2 minutes per sample with between 99.0% and 99.9% of fragments already corrected. We propose that GCparagon can help standardize cfDNA applications and evaluate the impact of GC bias on algorithms used in the analysis of liquid biopsy data.

Type: Other
Archiver: European Genome-Phenome Archive (EGA)

1 Dataset 1 Publication

Click on a Dataset ID in the table below to learn more, and to find out who to contact about access to these data

Dataset ID	Description	Technology	Samples
EGAD00001010100	These are aligned paired-end reads from Illumina NovaSeq 6000 whole-genome sequencing of 4 cfDNA samples extracted from blood plasma (plasma-Seq). Three samples from patients with breast cancer, prostate cancer, or colorectal cancer and one sample from a healthy individual were aligned to GRCh38 (GCA_000001405.15_GRCh38_no_alt_plus_hs38d1_analysis_set). The observed GC bias is different in each of these cfDNA samples which leads to different average GC content per sample. This bias is corrected using the GCparagon commandline tool.	Illumina NovaSeq 6000	2

Publications	Citations
GCparagon: evaluating and correcting GC biases in cell-free DNA at the fragment level. Spiegl B, Kapidzic F, Röner S, Kircher M, Speicher MR. NAR Genom Bioinform 5: 2023 lqad102	0