Hey Nicolas, Thanks for the reply. I have already used MSIsensor for 3 tumor samples. But I get 0 for "Number of sites with enough coverage" and "Number of somatic sites". How should I work further with MSIsensor?
Hi,
Could anyone suggest me free tools for calculating MSI for tumor samples alone?
TIA
2 answers
You can use MSIsensor
- tool : https://github.com/ding-lab/msisensor
- article : https://academic.oup.com/bioinformatics/article-lookup/doi/10.1093/bioinformatics/btt755
Tumor only mode :
# first scan genome of interest
msisensor scan -d reference.fa -o microsatellites.list
# Then use tumor bam file to detect MSI
msisensor msi -d microsatellites.list -t tumor.bam -e bed.file -o output.tumor.prefix
You should edit your question to add more informations regarding your data (which type : WGS, WES, targeted, etc... ). Without that I (and the community) would not be able to help you more.
Yeah, sorry about that. I have used MSIsensor for 3 different tumor exome samples without matched normal and getting 0 as the value for "Number of sites with enough coverage" and "number of somatic sites (%)" for all the 3 samples. I need to know whether the value I'm getting is correct or am I missing out on something.
Maybe check some sites in IGV to look if coverage is really low .. You could also reduce coverage thresold in msisensor mis with -c <int> coverage threshold for msi analysis, WXS: 20; WGS: 15, default=20
I had set the coverage threshold to -c 20 but I still get the output as 0. Below is the code I've used, kindly let me know if I've done it the right way:
msisensor msi -d microsatellites.list -c 20 -i 1 -t tumor.bam -e bed.file -o output.tumor.prefix
And. I'll also check some sites with IGV.
Hi, Output of a tumor only case, is 2144 3491 15.01. I have a few queries regarding it.
1.From the sample output given on the github page, I understand that 15.01 is the % of "Number of somatic sites" and is the msi score as well. Is it msi-high or msi-low? 2. What is the cutoff score? Because it is mentioned that the cutoff values are calculated for various cancer types. 3.How do I get the MSI status?
TIA
Figure 1 of the missensor paper seems explicit : https://academic.oup.com/bioinformatics/article/30/7/1015/236553 . As you have 15.01 % of somatic sites your sample should be MSI-H. The best would be to test on other samples ; and maybe on control samples (non-tumor) of the same tissue.
Hey, Thanks for the article. I have read it. Let me explain from what I understood from the graph is, <10% would be msi-low and >10% is msi-high. Did I get it right?
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