Chronic myeloid leukemia (CML) is a hematopoietic stem cell disease with distinct biological and clinical features. The Philadelphia (Ph) chromosome and BCR/ABL fusion gene is the major cytogenetic and molecular marker of CML chronic phase. However, the molecular mechanisms of disease progression are not well known. Recent studies have shown that a several of transcription factors such as AML1, C/EBPalpha, HOX and GATA family play important role in hematopoiesis. In addition, the aberrations of these transcription factors including mutations or translocations have also been found to contribute the disease progression. Hence, BCR/ABL and aberrant transcription factors may result in the phenotype of CML blast crisis together.