ERG and metastatic neoplasm: Analysis of published RNA-Seq tumor data sets from 21 patients with EwS (29) confirmed the expression of HSAT2,3 RNAs in primary and metastatic tumors, including cases with EWS:FLI1 (n = 16) and EWS:ERG (n = 5) fusions, and their origins from the 4p11, 10q11.21, and 16q11.2 HSAT2,3 loci (Figure 3, C and D).