MRC1 and pleomorphic rhabdomyosarcoma: In another recent NGS study, MMR deficiency was identified in 2.3% (7/304) of sarcomas (4 unclassified sarcomas, 1 pleomorphic rhabdomyosarcoma, 1 epithelioid leiomyosarcoma, and 1 malignant perivascular epithelioid cell neoplasm).