A study on cytogenetics and molecular genetics in chronic myeloid leukemia blast crisis

Objective To study the changes of cytogenetics and molecular genetics in chronic myeloid leukemia blast crisis(CML-BC).Methods Cytogenetic preparantions from 25 cases in CML-BC selected randomly were assayed with conventional cytogenetic analysis and dual color dual fusion fluorescence in situ hybridization(FISH) technique.If there was only one fusion signal detected by FISH technique in interphase cells,metaphase cells were simultaneously observed to determine if there were the deletions on the der(9).Results Of 25 cases selected randomly,5 with der(9) deletions were detected by FISH technique,while R banding revealed no der(9) deletions in all 25 cases.The cases with der(9) deletions were demonstrated no trend of instability in cytogenetics.Those with new cytogenetic abnormalities in CML-BC had shorter duration of CML-BC.There was no significant difference in the propability of the der(9) deletions between the cases transforming to acute lymphoid leukemia and those transforming to acute non-lymphoid leukemia.Conclusion FISH could effectively show the der(9) deletions,and the der(9) deletions might not lead to instability in cytogenetics of CML-BC and transformation to specific type in CML.