PAX3 and synovial sarcoma: It is important to note that aberrant expression or overexpression of MUC4 has also been reported in various carcinomas, including pancreas, ovary, lung, breast, colon, prostate, and myoepithelial carcinoma, and in mesenchymal tumors, including SEF, synovial sarcoma, ossifying fibromyxoid tumor, epithelioid gastrointestinal stromal tumors, and PAX3/7::FOXO1 fusion‐positive rhabdomyosarcomas.25, 27, 29, 30, 31, 32