Using ABSOLUTE's estimates of purity and genome-wide integer copy-numbers, we can calculate the required coverage for powered detection of mutations present at specified allelic multiplicity per cancer cell. Similar considerations apply to detecting subclonal mutations, present in a fraction of cancer cells, by using fractional multiplicities (Supplementary Fig. 7c). We note that consideration of tumor purity in units of cells, rather than DNA fraction, is preferred for devising power calculations for sequencing experiments, since many somatic alterations of interest are expected to occur at a single copy per cancer cell.
