Fig. 1.

Temporal dissection of mutations and mutational processes in TCGA samples. Integration of copy number, purity estimates, and VAF of each somatic mutation permits calculation of the cancer cell fraction, describing the fraction of cancer cells with an alteration. The mutation copy number can also be estimated, allowing further timing of mutations in the case of a genome-doubling or amplification event. These data can reveal the clonality of driver events and shifts in mutational spectra and mutational signatures over time, as well as permitting identification of driver genes using subclonal mutations. a.u., arbitrary unit.