PAX7 and embryonal rhabdomyosarcoma: In juvenile cases, reports indicate that MEM, similar to ERMS, exhibits trisomy of chromosomes 2, 8, and 11.[13] MEM containing ERMS components exhibits high-frequency HRAS mutations consistent with ERMS,[14] while MEM with ARMS components demonstrates corresponding abnormal fusions such as PAX3-FOXO1/PAX7-FOXO1.