[A clinical and laboratory study of 11 cases of t(6;11)(q27;q23) acute leukemia].

Objective: To analyse the morphologic, immunophenotypic, cytogenetic and clinical features of acute leukemia with t(6;11)(q27;q23).

Methods: Cytogenetic examination of bone marrow cells was performed with direct method or 24 h culture method. R-bands by heating using Giemsa (RHG) banding technique was used for karyotype analysis. mixed lineage leukemia (MLL) rearrangement was detected by interphase fluorescence in situ hybridization (FISH) using dual-color MLL probe in 10 cases. Chromosome painting was performed by using whole chromosome paints 6 and 11 in 5 cases.

Results: t(6;11)(q27;q23) was predominantly found in acute myeloid leukemia (AML)-M(5) (8/11 cases). Increased WBC between 10 and 100 x 10(9)/L was found in 9 cases. Liver, spleen and/or lymph node infiltrations were found in 9 cases. t(6;11) as a sole abnormality was detected in 9 cases, However, additional aberrations besides t(6;11) were detected in the other two cases. Dual-color FISH analysis detected the MLL rearrangement in 10 cases. A reciprocal translocation between 6 and 11 was proved by chromosome painting technique in 5 cases. The immunophenotypical analysis of leukemia cells showed co-expressed myeloid and lymphocyte antigens in 4 cases. Blast cells were positive for CD(34) antigen in 8 patients except case 8. Median survival was 6 months in this series.

Conclusions: t(6;11) acute leukemia had unique clinical features and a poor prognosis. Chromosome painting technique and dual-color FISH are reliable tools for detecting this translocation and MLL rearrangement respectively.