ERG and glioblastoma: This is supported by our observation that some cancer types, such as GBM, have a low burden of SNAs (Fig. 2E) and CNAs (Fig. 2F) in ERGs, in line with a low within-tumor variation in ERG expression (Fig. 3A), but a high number of ERGs with deregulated expression in tumor samples relative to adjacent normal tissue (Fig. 3E–G) and vice versa (e.g., STAD).