Racial Differences in the Incidence of Mesenchymal Tumors Associated with EWSR1 Translocation

BACKGROUND: The incidence of Ewing sarcoma varies by race, with very low rates among persons of African and East Asian ancestry. The incidence by race of other mesenchymal tumors that also harbor EWSR1 translocations has not been studied. METHODS: The SEER database was queried to find cases of mesenchymal tumors associated with EWSR1 translocations: Ewing sarcoma; clear cell sarcoma; extraskeletal myxoid chondrosarcoma; myxoid liposarcoma; desmoplastic small round cell tumor; and myoepithelial tumor. Age-adjusted incidence rates were calculated for white, African American, and Asian/Native American populations and compared statistically. RESULTS: Ewing sarcoma was significantly less common in the African American and Asian/Native American populations compared with the white population, with incidence rate ratios of 0.12 (95% CI, 0.08-0.20; P<0.001) and 0.54 (95% CI, 0.41-0.69; P<0.001), respectively. Desmoplastic small round cell tumor was significantly more common in the African American population compared with the white population (incidence rate ratio=3.0; 95% CI, 1.62-5.49; P<0.001). Myxoid liposarcoma was significantly less common in the Asian/Native American population compared with the white population (incidence rate ratio=0.72; 95% CI, 0.56-0.92; P=0.006). The incidence rates for extraskeletal myxoid chondrosarcoma, myoepithelial tumors, and clear cell sarcoma did not differ significantly by race. CONCLUSIONS: Tumors associated with EWSR1 translocation are not uniformly more common in people of European ancestry. IMPACT: The relationship between race and EWSR1 somatic translocation is complex. Future studies investigating the genetic epidemiology of EWSR1 translocated tumors are required.