Genomic DNA sequences derived from t(12;16) and t(12;22) were amplified by long-distance polymerase chain reaction (PCR) in six cases of MLS, and the DNA sequences around the breakpoints were analysed.
The third case of t(12;16) MLS had a break upstream and near a TC-dinucleotide repeat region and a sequence similar to the chi bacterial recombination element was found to flank the breakpoint.
We have analyzed peripheral blood samples obtained during a 10-year period at diagnosis of primary and/or recurrent disease in 19 MLS patients with t(12;16) and in one MLS patient with t(12;22;20), resulting in the fusion of the CHOP and EWS genes.
The FUS gene, which maps to 16p11, is fused to the CHOP gene in the t(12;16) (q13;p11) that characterizes myxoid liposarcomas (MLS) and to the ERG gene in acute myeloid leukemia (AML) with t(16;21) (p11;q22).
In another patient the karyotypes obtained in the 26th and 28th yr of his disease were similar and included the t(12;16) (q13;p11), characteristic of MLS.