[Conventional cytogenetics and fluorescence in situ hybridization as methods for detecting MLL gene rearrangements in...

This study was aimed to compare the values of conventional cytogenetics (CC), interphase FISH and sequential R-banding and FISH analysis as methods for detecting MLL gene rearrangements. 37 acute leukemia patients were studied by CC and interphase FISH. The results showed that among them, 10 cases were 11q23(+)/MLL(+), 2 cases were 11q23(-)/MLL(+) (5.4%), 3 cases were 111q23(+)/MLL(-) (8.1%) and 22 cases were 11q23(-)/MLL(-). For some patients, different results were obtained by using CC and interphase FISH for detecting 11q23/MLL gene rearrangements. After sequential R-banding and FISH analysis for 6 patients, the chromosome related to MLL gene translocation was seen clearly in karyotypes and FISH image. It is concluded that for accurate diagnosis both CC and FISH are needed for detecting 11q23/MLL gene rearrangements, and evaluation is needed in combination of these two results. When necessary, it needs to do sequential R-banding and FISH or molecular analysis.