TRANSLOCATION T(12-16)(Q13-P11) IN MYXOID LIPOSARCOMA AND ROUND-CELL LIPOSARCOMA - MOLECULAR AND CYTOGENETIC ANALYSIS

Translocation t(12;16)(q13;p11) is regarded as a diagnostic marker for myxoid liposarcoma. Cytogenetic data on round cell liposarcomas and c ombined myxoid and round cell tumors is scarce, and the genetic basis of progression of myxoid tumors to high grade, round cell lesions is u nknown. We have accumulated six round cell, four combined myxoid and r ound cell, and three myxoid liposarcomas for analysis, t(12;16)(q13;p1 1) was present in three round cell lesions and was detectable in all o f the tumors by DNA analysis. In each tumor type, the CHOP gene in 12q 13 was rearranged and fused to the TLS gene in 16p11. A variant TLS-CH OP RNA transcript was detected by polymerase chain reaction but did no t correlate with clinicopathological data. No distinguishing cytogenet ic or molecular markers for round cell or mixed lesions were found, Th e histogenic and genetic relatedness of myxoid and round cell liposarc omas is apparent from these data.