A viral etiology for Ewing's sarcoma.

Despite the finding of characteristic somatic mutations in the tumor tissue and efforts to identify risk factors, the etiology of Ewing's sarcoma (ES) is still unknown. ES is very different from other childhood bone cancers. It rarely occurs in the black population and has no animal model. Recently studies indicate that ES may have a neural, not mesenchymal, origin. It has a distinctive unimodal age-incidence peak at adolescence. Because its incidence curve pattern has a striking resemblance to that of DES-related clear cell adenocarcinoma of the vagina, an in utero exposure might be considered. Although in utero chemical and hormonal exposures have not been found to be associated with ES in epidemiologic studies, we suggest that its etiology could be an in utero viral infection. We hypothesize that the epidemiological characteristics of ES suggest an association with cytomegalovirus (CMV).