SS18 and neoplasm: When SMARCB1 fl mice were crossbred with hSS2 mice expressing the SS18-SSX fusion gene, sarcomagenesis was significantly enhanced with 100% penetrance and shorter tumor latency, however, tumor histology and molecular profile were more similar to epithelioid sarcomas or malignant rhabdoid tumors (MRTs), two tumor histotypes both characterized in patients by homozygous loss of function of SMARCB1.