What type of cancer is primarily associated with the EWSR1 gene fusion?

The EWSR1 gene fusion is primarily associated with Ewing Sarcoma, a type of bone cancer that typically affects children and young adults. This fusion involves the EWSR1 gene, which may combine with various partners, most commonly the FLI1 gene, leading to the formation of a fusion protein that disrupts normal cellular functions and promotes tumor development. The presence of the EWSR1 gene fusion is a critical diagnostic marker for Ewing Sarcoma, thereby aiding in the identification and confirmation of this specific cancer type. Given the strong association between this gene alteration and Ewing Sarcoma, it serves as a key element in both understanding the pathology of the disease and guiding treatment options.