Indeed, infrequent but focal CNAs can be highly informative as they may point to genes that are activated or silenced by other means, such as deletions of APAF1 and FBXW7. APAF1 maps to 12q22-23, a region associated with common LOH in GBM (Watanabe et al., 2003). Here, FBXW7 is linked to glioblastoma.