A Molecular Cytogenetic Study On Acute Myeloid Leukemia With Inversion Of Chromosome 16

Objective: To explore the value of defferent FISH techniques in the detection of inv(16) in AML.Methods: Four kind of probes consisting of MYH11 single-color DNA probe, MYH11 dual-color DNA probe, 16q probe and chromosome 22 specific centromeric DNA probe and three kind of FISH techniques consisting of dual color-FISH, chromosome painting (CP) and single- color FISH to detect inv(16) and trisomy 22 in 50 AML patients(7M4Eo,11M4,9M5, 23M2).The results were associated or compared with those of cell morphology, conventional cytogenetics(CC) and RT-PCR.Results: RT-PCR was used in 46 patients. Among them, 7 were positive for CBFβ/MYH11 fusion gene transcripts. Single-color FISH was made in 20 patients. Of them, 11 cases comprising the 7 cases with positive RT-PCR as mentioned above were positive, 6 cases were negative and 3 cases were false posive because their mean positive cells ratio was slightly more than X+3SD of the control and their RT-PCR showed negative results. D-FISH was performed in 12 patients. Of them, 11 cases were positive(7M4Eo, 2M4, 2M2) and one case was negative. The latter has a positive cells ratio slightly more than X+3SD of the control on single-color FISH assay. Five cases were found havingdistinctive inv(16) on CP. 2 cases were positive for +22 by single color FISH with CEP22 probe and for inv(16) by dual- color FISH. G/R-banded karyotypic analysis detected only four with inv(16) and 2 with trisomy 22. Conclusion:(1)Comparing to CC, FISH can increase the detecting rate of inv(16) significantly. D-FISH has stronger specificity and better concordance with RT-PCR.(2)Trisomy 22 has the value of forecasting inv(16)AML for it's easy to be recognized. (3)In order to raise the detecting rate of inv(16), it is necessary to use FISH and/or RT-PCR to screen all of the AML patients whether or not they have bone marrow abnormal eosinophilia.