Using a rule-based algorithm to define minimal common regions (MCRs) of CNAs based on amplitude, width, and recurrence of CNAs (Aguirre et al., 2004; Carrasco et al., 2006; Tonon et al., 2005), we readily identified the signature genomic events known previously for GBM (e.g., EGFR amplification or CDKN2A deletion) as well as many previously uncharacterized alterations (Table S2). The gene discussed is CDKN2A; the disease is glioblastoma.