Acute myeloid leukemia with inv(16)(p13.1q22) and deletion of the 5'MYH11/3'CBFB gene fusion: a report of two cases and literature review

Abnormalities of chromosome 16 are found in about 5-8% of acute myeloid leukemia (AML). The AML with inv(16)(p13.1q22) or t (16;16)(p13.1;q22) is associated with a high rate of complete remission (CR) and favorable overall survival (OS) when treated with high-dose Cytarabine. At the inversion breakpoints, deletion of 3' has been reported, but most of them were studied by chromosome and fluorescence in situ hybridization (FISH) analyses. The genomic characteristics of such deletions remain largely undefined, hindering further understanding of the clinical significance of the deletions. We report here two AML cases with inv(16) and deletion of the 5' /3' gene fusion, which were characterized by chromosome, FISH, and single nucleotide polymorphism (SNP) microarray analyses. Both cases have achieved CR for more than three years. Deletion of 3' in AML with inv(16) is also accompanied with deletion of 5' in all the cases studied by SNP microarray, suggesting that 3' and 5' were most likely deleted together as a fusion product of inv(16) instead of occurring separately. In concert with the findings of other published studies of similar patients, our study suggests that deletion of 5' /3' in AML with inv(16) may not have negative impact on the prognosis of the disease.