Analysis of the predicted absolute allelic copy-number profiles across human cancers produced by ABSOLUTE shed new light on cancer genome evolution. The observed SCNA profiles (Supplementary Fig. 9) were consistent with a common trajectory consisting of an early period of chromosomal instability followed by the emergence of a stable aneuploid clone, as previously described 11. Our data further indicate that genome doublings occur in a subset of cancer cells already harboring arm-level SCNAs characteristic of the corresponding tumor type. The genomes of these cancers were therefore shaped by selection at chromosomal arm-level resolution prior to doubling and further clonal outgrowth (Fig. 6d, Supplementary Fig. 10).
