RB1 and sarcoma: Using extensive multiplatform profiling, we confirmed that PRMS is highly rearranged with multiple copy-number gains and losses, and a large majority of samples harbor losses and rearrangements in TP53 and RB1. These features in PRMS are similar to those of other complex sarcoma subtypes such as UPS, LMS, and OS and are in contrast to the simple genomes found in ARMS and ERMS.51