Professional
Technical
IVT
allelic fraction
The proportion of sequencing reads containing a specific variant compared to total reads at that genomic position.
Full Definition
In precision oncology, allelic fraction represents the percentage of DNA molecules that carry a particular mutation at a given genomic locus. This metric is crucial for determining the clonality of mutations, assessing tumor purity, and monitoring treatment response. Low allelic fractions may indicate subclonal mutations or contamination with normal tissue, while high frelic fractions suggest dominant clones or high tumor purity.
Usage
Usage note: Often abbreviated as VAF in clinical reports; ensure consistency with institutional preferences.
In Context
- "The allelic fraction of the EGFR L858R mutation was 42%, indicating a dominant clone." — Genomic sequencing report
- "Serial monitoring showed decreasing allelic fractions of driver mutations following targeted therapy." — Treatment response assessment
Also known as
variant allele fraction
VAF
mutant allele frequency
Don't confuse with
allelic imbalance
loss of heterozygosity