We then explored ERK5 protein expression in human tumors from patients diagnosed with different sarcoma subtypes obtained from our University Hospital: leiomyoma (n = 11), leiomyosarcoma (n = 12), lipoma (n = 5), liposarcoma (n = 12), rhabdomyosarcoma (n = 4), schwannoma (n = 1), malignant peripheral nerve sheath tumor (n = 4) and undifferentiated pleomorphic sarcoma (n = 10). This evidence concerns the gene MAPK7 and rhabdomyosarcoma.