AXL and sarcoma: In sarcomas specifically, AXL messenger RNA (mRNA) expression levels are significantly elevated in comparison with levels in other cancer types and in normal tissue.5 Among sarcomas, AXL mRNA expression is highest in MFS.5 Accordingly, a patient-derived xenograft study demonstrated that MFS showed the highest and most stable expression of AXL protein compared with other sarcoma types.6 Nevertheless, the pathogenic significance of these findings remains unknown.