In GBM samples, LOH involving chromosomes 9 and 10, and gains of chromosome 7 occurred at equivalent frequencies (Fig. 6d), demonstrating that the most common broad SCNAs in GBM occur prior to genome doubling. Gain of chromosomes 19 and 20 was nearly exclusive to non-doubled samples, and several arms had greater LOH frequency in doubled samples (Fig. 6d), suggesting that additional biological differences underlie these samples.
