TMAs with the successive tumour passages that grew in nude mice (XT/OT and XT/CC) were analyzed by morphologic pattern (Hematoxilin/eosin), immunohistochemical staining (CD99, FLI1, p16, p53, ki-67), fluorescent in situ hybridization-FISH-(EWSR1 break apart, p16 and p53 status) and gene fusion types. The gene discussed is CD99; the disease is neoplasm.