What causes Ewings sarcoma?
The majority of Ewing’s sarcomas result from a chromosome rearrangement between chromosomes #11 and #22. This rearrangement changes the position and function of genes, causing a fusion of genes referred to as a “fusion transcript.” Over 90 percent of individuals have an abnormal fusion transcript, involving two genes known as EWS and FLI1. This important discovery has led to improvements in diagnosing Ewing’s sarcoma. Similar to osteosarcoma, trauma or injury is sometimes involved with the site at the time of diagnosis. However, this trauma is thought to bring the condition to attention rather than to have any causal relationship. Some physicians classify Ewing’s sarcoma as a primitive neuroectodermal tumor (PNET). This means the tumor may have started in fetal, or embryonic, tissue that has developed into nerve tissue.
