Trisomy 22 as the sole abnormality is an important marker for the diagnosis of acute myeloid leukemia with inversion 16

Background: The inversion of chromosome 16 (inv(16) (p13q22)) and the related t(16; 16)(p13; q22) are chromosomal aberrations observed in approximately 10% of de novo acute myeloid leukemia (AML), mostly classified as M4Eo subtype, and associated with a relatively favorable outcome. However, it is a cryptic rearrangement and often difficult to recognize in conventional cytogenetics (CC). Trisomy 22 is an uncommon karyotypic aberration in AML and is often associated with inv(16)( p13q22). The aim of this study was to explore the value of trisomy 22 in the diagnosis of AML with inv(16). Patients and Methods: Dual-color interphase fluorescence in situ hybridization (FISH) was performed in 19 AML cases with trisomy 22 abnormality shown by R-banding CC. The probe was a two-color break-apart probe for CBF beta on the centromeric side and the telomeric side. Results: R-banding CC did not reveal inv(16) in any of the 19 AML with trisomy 22, but FISH analysis showed inv(16) in 11 cases and del(16)(q22) in 1 case. Among the 11 cases with inv(16), 9 showed trisomy 22 as the sole abnormality, 1 was complicated by trisomy 8, and 1 was del(16)(q22). Conclusion: This study further confirmed that trisomy 22 as the sole abnormality can be regarded as an important marker for inv(16) in AML.