Question: Why there is a 50% variant allele frequency in TCGA NSCLC data?
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gravatar for sm.hashemin
5 months ago by
sm.hashemin90
sm.hashemin90 wrote:

Hi, I was taking a lot at the variant allele frequencies in TCGA NSCLC data (from the the MAF somatic SNV file). I have seen thet the highest VAF is 50% and it apears that they have a cutoff there. Does it mean that a SNV of 60% vaf can not be a homozygous mutations in 60% of cells (while tumor purity of 60%) or a subclonal snv at higher purities?

As well there is a lot of variants with 0% VAFs! which is also strange.

What I want to learn from this story is: what should I consider when facing a oncoplot? can a variant on oncoplot have only 3% vaf? specially in paired primary vs recurrent tumors, can it be that a variant is simply missing in one because it has a less than cutoff level vaf ?

Best

ADD COMMENTlink modified 25 days ago • written 5 months ago by sm.hashemin90
1
gravatar for sm.hashemin
25 days ago by
sm.hashemin90
sm.hashemin90 wrote:

Answering myself: because mutations are considered to happen in heterozygous state, therefore at 100% purity you will have a 50% VAF. VAF of more than 50% belongs to the LOHs.

ADD COMMENTlink written 25 days ago by sm.hashemin90
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