Diagnostic value of fluorescence in situ hybridization for the detection of genomic aberrations in older patients with acute myeloid leukemia.

Background And Objectives: Karyotype is one of the most important prognostic factors in acute myeloid leukemia (AML).

Design And Methods: To assess the diagnostic value of molecular cytogenetics in AML patients older than 60 years, we compared the results of chromosome banding with those of fluorescence in situ hybridization (FISH) applying a comprehensive DNA-probe set for the detection of the most relevant AML-associated chromosome aberrations in a prospective series of 283 patients registered for the multicenter treatment trial AML HD98-B.

Results: Four cases of inv(16)/t(16;16) and 2 cases of t(11q23) were only detected by FISH. Molecular cytogenetic analysis was also more sensitive for the detection of genomic imbalances, in particular 7q-, +11q, 17p-, and 20q-, but virtually all cases of aneuploidy or deletions that were missed on banding analysis were identified in patients without assessable metaphases, in patients with normal karyotypes but poor chromosome morphology, in patients with a leukemia-specific balanced rearrangement, or in patients with complex karyotypes.

Interpretation And Conclusions: Our results support the use of FISH as a complementary method for the detection of inv(16)/t(16;16) and t(11q23) in all older AML patients eligible for intensive therapy. Molecular cytogenetics should also be considered in cases with insufficient yields of metaphase cells, poor chromosome morphology, or both. Routine screening for chromosomal imbalances by FISH does not improve cytogenetic risk assessment in patients with adequate pretreatment karyotype information.