Objective: To study the gene expression profile of chronic myeloid leukemia (CML) in chronic and blast phases for providing information about the potential mechanisms of blastic crisis.

Methods: The gene expression difference of bone marrow mononuclear cells between CML in chronic and in blastic phases was examined with DNA array.

Results: In the blastic phase, 68 genes were obviously up-regulated in the 1176 tested genes. Among the 68 genes, the transcription factors accounted for 23.5%, cell surface antigens 22.1%, regulation proteins 19.1% and others 35.3%. There were 17 genes expressed only in the blastic phase and 11 (16.2%) genes related to G protein.

Conclusions: Obvious difference of gene expression profile existed between chronic and blastic phases of CML. Up-regulation of gene expression is one of the characteristics of CML in blastic phase. The genes related to G protein may play an important role in the blastic transformation of CML.