Causes

It's not clear what causes Ewing sarcoma.

Doctors know that Ewing sarcoma begins when a cell develops changes in its DNA. A cell's DNA contains the instructions that tell a cell what to do. The changes tell the cell to multiply quickly and to go on living when healthy cells would normally die. The result is a mass (tumor) of abnormal cells that can invade and destroy healthy body tissue. The abnormal cells can break away and spread (metastasize) throughout the body.

In Ewing sarcoma, the DNA changes most often affect a gene called EWSR1. If your doctor suspects that you have Ewing sarcoma, your cancer cells may be tested to look for changes in this gene.