Which biomarker is widely used in the diagnosis of Ewing sarcoma?
["half of B-LBL patients are negative for CD45 (leucocyte common antigen, LCA), a widely used marker for the diagnosis of lymphoma, and a significant portion express CD99, a marker for Ewing's sarcoma (ES) or primitive neuroectodermal tumor (PNET)", "Moreover, half of B-LBL patients are negative for CD45 (leucocyte common antigen, LCA), a widely used marker for the diagnosis of lymphoma, and a significant portion express CD99, a marker for Ewing's sarcoma (ES) or primitive neuroectodermal tumor (PNET)"]
['CD99 is a hallmark marker for Ewing sarcoma and primitive neuroectodermal tumors.']
['CD99']