EWSR1 and Ewing sarcoma: Due to its unique expression in Ewing tumors, several studies have shown that NKX2.2 is a valuable immunohistochemical marker for EwS detection, with higher sensitivity and specificity than other EWSR1-FLI1-induced genes, including NR0B1, E2F3, and EZH2 [96,97,98,99,100].