Finally, cytogenetic studies can look for the characteristic translocation t (11; 22) (q 24;12) that causes mutation of EWS gene resulting in EWS-FLI1 fusion protein identified in 85%–90% of peripheral PNET neuroepithelioma and Ewing's sarcoma [2, 4, 8]. This evidence concerns the gene EWSR1 and primitive neuroectodermal tumor.