Another complex genomic profile, called 'sawtooth,' was present in 5% of breast cancer samples. It was characterized by narrow, low-copy-number deletions and duplications that were evenly distributed across the chromosomes. The 'simplex' profile, affecting 60% of the tumor samples, exhibited broad genomic duplications and deletions that only affected a single chromosomal arm. The remaining 10% of the samples exhibited a 'flat' profile, reflecting normal levels of copy number variation in the genome (see http://www.cshl.edu/public/releases/genome.html).
In addition to potential clinical applications, the profiles described in this study will be useful for assessing the relationship between 'firestorms' and the locations of candidate oncogenes and tumor suppressors in the genome. It will assist the researchers in identifying genes that drive cancer progression, and help unravel the complex yet elusive genetic pathway that underlies tumor metastasis.