calculatePowerDetectSomatic {PureCN} | R Documentation

## Power calculation for detecting somatic mutations

### Description

This function calculates the probability of correctly rejecting the null hypothesis that an alt allele is a sequencing error rather than a true (mono-)clonal mutation.

### Usage

    calculatePowerDetectSomatic(coverage, f = NULL, purity = NULL,
      ploidy = NULL, cell.fraction = 1, error = 0.001, fpr = 5e-07,
      verbose = TRUE)

### Arguments

`coverage` | Mean sequencing coverage.
`f` | Mean expected allelic fraction. If `NULL`, requires purity and ploidy and then calculates the expected fraction.
`purity` | Purity of sample. Only required when `f` is `NULL`.
`ploidy` | Ploidy of sample. Only required when `f` is `NULL`.
`cell.fraction` | Fraction of cells harboring mutation. Ignored if `f` is not `NULL`.
`error` | Estimated sequencing error rate.
`fpr` | Required false positive rate for mutation vs. sequencing error.
`verbose` | Verbose output.

### Value

A list with elements

`power` | Power to detect somatic mutations.
`k` | Minimum number of supporting reads.
`f` | Expected allelic fraction.

### Author(s)

Markus Riester

### References

Carter et al. (2012), Absolute quantification of somatic DNA alterations in human cancer. Nature Biotechnology.

### Examples

    purity <- c(0.1,0.15,0.2,0.25,0.4,0.6,1)
    coverage <- seq(5,35,1)
    power <- lapply(purity, function(p) sapply(coverage, function(cv)
        calculatePowerDetectSomatic(coverage=cv, purity=p, ploidy=2,
        verbose=FALSE)$power))

    # Figure S7b in Carter et al.
    plot(coverage, power[[1]], col=1, xlab="Sequence coverage",
        ylab="Detection power", ylim=c(0,1), type="l")

    for (i in 2:length(power)) lines(coverage, power[[i]], col=i)
    abline(h=0.8, lty=2, col="grey")
    legend("bottomright", legend=paste("Purity", purity), fill=seq_along(purity))

    # Figure S7c in Carter et al.
    coverage <- seq(5,350,1)
    power <- lapply(purity, function(p) sapply(coverage, function(cv)
        calculatePowerDetectSomatic(coverage=cv, purity=p, ploidy=2,
            cell.fraction=0.2, verbose=FALSE)$power))
    plot(coverage, power[[1]], col=1, xlab="Sequence coverage",
        ylab="Detection power", ylim=c(0,1), type="l")

    for (i in 2:length(power)) lines(coverage, power[[i]], col=i)
    abline(h=0.8, lty=2, col="grey")
    legend("bottomright", legend=paste("Purity", purity), fill=seq_along(purity))

[Package PureCN version 1.18.1 Index]