We then describe how estimates of tumor purity and absolute copy-number allow us to analyze sequencing data to distinguish clonal and subclonal point-mutations, and to detect macroscopic subclonal structure in an ovarian cancer sample. Clonal events may be classified as homozygous or heterozygous in the cancer cells, guiding interpretation of their function. In addition, the ability to quantify integer multiplicity of point mutations distinguishes events occurring prior to DNA gains including the mutated locus from those occurring later.
