this chromosomal anomaly results following the fusion of a gene from the 16th chromosome, called FUS/TLS (fused in sarcoma / translocated in liposarcoma) with a gene from the 12th chromosome, called CHOP, that codifies a nuclear protein that is an inhibitor transcription factor, dominantly negative, from the factor class C/EBP – enhancer binding protein and LAP (latency associated peptide) – see translocation EWS – CHOP t(12, 22) (q13; q12). This evidence concerns the gene EWSR1 and sarcoma.