Of non-gastrointestinal mesenchymal tumors, alveolar rhabdomyosarcoma (50%, Figure 2A), nephroblastoma (38%, Figure 2B), angiosarcoma (36%), desmoplastic small round cell tumors (29%), alveolar soft part sarcoma (18%), PEComa (17%), and embryonal rhabdomyosarcoma (15%), showed CD171 positivity in >10% of cases. The gene discussed is L1CAM; the disease is mesenchymal cell neoplasm.