EWSR1 is a gene located on chromosome 22 in humans. It encodes a protein that plays a crucial role in various cellular processes, including gene regulation and RNA processing. Mutations or alterations in the EWSR1 gene can lead to the development of certain types of tumors, particularly in soft tissues. One of the most notable associations of EWSR1 is with Ewing sarcoma, a rare and aggressive cancer that primarily affects children and young adults. In many cases, EWSR1 fusions with other genes, such as FLI1, contribute to the formation of this cancer, highlighting the gene's significance in oncogenesis.