Objective: To explore genes involved in chronic myeloid leukemia (CML) with t (3; 21) (q26; q22) chromosome translocation in blastic crisis.
Methods: A case of CML patient with t (3; 21) (q26; q22) in blastic crisis was reported. AML1 and bcr/abl genes were detected by FISH in interphase and metaphase cells. Genes involved in t (3; 21) (q26; q22) were analysed by RT-PCR and sequencing.
Results: AML1 gene hybridization signal was detected in der (3) and der (21) chromosomes. AML1-Evi1, AML1-MDS1-Evi1, AML1-EAP fusion transcripts and Evi1 gene were detected in mRNA level, but no AML1-Evi1 fusion transcript. The mRNA expression level of AML1-MDS1-Evi1 fusion gene was 1.58 and 1.54 times higher than that of AML1-MDS1 and AML1-EAP, respectively. The mRNA expression level of Evi1 gene of the patient was 2.71 times higher than that of HEL cell line.
Conclusion: t (3; 21) (q26; q22) resulted in the AML1-MDS1-Evi1, AML1-MDS1, AML1-EAP fusion transcripts, and Evi1 gene was also activated by the translocation. These secondary aberrations should be the molecular basis of CML patient with t (3; 21) (q26; q22) in blastic crisis.