Estimating tumor fraction by exploiting the off-target reads in targeted DNA sequencing.
The ichorCNA_offtarget.snakefile workflow will run the ichorCNA off-target pipeline, starting from bam files and generating files and plots documenting copy number alterations across the genome.
The plotCNAzoom_offtarget.snakefile workflow will use the results of ichorCNA_offtarget.snakefile and zoom in on particular regions of interest, producing plots that provide a closer look at copy number alterations in those regions.
- R-3.3 or above
- ichorCNA
- HMMcopy
- optparse
- Python-3.4 or above
- snakemake-3.12.0 or above
- PyYAML-3.12 or above
- HMMcopy Suite (http://compbio.bccrc.ca/software/hmmcopy/)
- In particular, readCounter is used.
- ichorCNA repository (https://github.com/broadinstitute/ichorCNA)
Please specify the samples to be analyzed in config/samples.yaml, following the format explained therein.
There are a number of parameters to adjust in config/config.yaml. Filepaths to where your ichorCNA repository (https://github.com/broadinstitute/ichorCNA) clone was downloaded to must be inserted in a few places, as well as the filepath to your readCounter binary. A nice description of some of the other parameters that can be adjusted, such as bin size and segmentation settings, can be found in the README.md for the snakemake workflow of regular (not off-target) ichorCNA, at https://github.com/broadinstitute/ichorCNA/wiki/SnakeMake-pipeline-for-ichorCNA.
Currently, this code handles .bed files of targeted regions with no headers and at least 5 columns. Please ensure your .bed file follows this formatting, or change the following code in code/ichorCNA_offtarget.R to fit your purposes:
baits <- fread(baitFile.tum, skip=0)
colnames(baits) <- c("chr", "start", "end", "name", "strands")
To invoke the snakemake workflows locally, use
snakemake -s ichorCNA_offtarget.snakefile
and
snakemake -s plotCNAzoom_offtarget.snakefile
To run the snakemake workflows on a slurm cluster, use
snakemake -s ichorCNA_offtarget.snakefile --latency-wait 60 --cluster-config config/cluster_slurm.yaml --cluster "sbatch -p {cluster.partition} --mem={cluster.mem} -t {cluster.time} -c {cluster.ncpus} -n {cluster.ntasks} -o {cluster.output}" -j 50
and
snakemake -s plotCNAzoom_offtarget.snakefile --latency-wait 60 --keep-going --cluster-config config/cluster_slurm.yaml --cluster "sbatch -p {cluster.partition} --mem={cluster.mem} -t {cluster.time} -c {cluster.ncpus} -n {cluster.ntasks} -o {cluster.output}" -j 50
To perform a dry run, where the commands to be executed will be printed, but the snakefile will not actually be run, add -np at the end of these commands. This helps to verify the workflow will run as expected.