EWSR1 and neoplasm: One study used indirect immunofluorescence to detect 8H9 (a monoclonal antibody targeting tumor-associated B7-H3) immunoreactivity in Ewing/primitive neuroectodermal tumor cell lines, in which two-third of samples were strongly positive and the rest were weakly positive, strongly supporting the presence of B7-H3 expression in EWS (71).