OBJECTIVETo investigate the characteristics of the abnormalities of chromosome 17 in myeloid malignancies with complex chromosomal abnormalities (CCAs).

METHODSAbnormalities of chromosome 17 were analyzed in 73 patients with myeloid malignancies with CCAs showed by R banding and conventional karyotyping, including 21 acute myeloid leukemia (AML), 36 chronic myeloid leukemia (CML) and 16 myelodysplastic syndrome (MDS). All CCAs were further analyzed by multiplex fluorescence in situ hybridization (M-FISH).

RESULTSAmong the 73 myeloid malignancies with CCAs, chromosome 17 was the most frequently involved chromosome. It was found in 46.5% (34/73) of all cases, including 12 AML, 13 CML in blast crisis (BC) and 9 MDS. However, it was not found in the 9 CML cases in chronic phase (CP). The majority of changes were structural rearrangements which were identified in 43.8%(32/73)of all cases, among them the frequency was 52.4% (11/21), 33.3% (12/36) and 56.3% (9/16) in AML, CML and MDS, respectively. Numerical abnormalities were detected in 15.1% (11/73) cases, all were monosomy 17, and the frequency was 25.0% (3/12), 38.5% (5/13) and 33.3% (3/9) in AML, CML and MDS, respectively. Both numerical and structural abnormalities of chromosome 17 were found in 9 cases. Unbalanced translocations involving chromosome 17 were much more frequent than balanced ones. In the 3 groups, 16, 15 and 8 unbalanced translocations were found respectively. Only two kind of balanced translocations including t(15;17) in AML and t(15;17;22) in CML were found. All chromosomes were involved except chromosomes 5, 6 and 22 as partner chromosomes, the most common one was chromosome 15 (8.2%), followed by chromosome 2 (5.4%). Five of the 6 cases with translocation of chromosomes 15 and 17 were acute promyelocytic leukemia, the other case was CML-BC.

CONCLUSIONAbnormalities of chromosome 17 were the most frequently involved chromosomal aberrations in myeloid malignancies, and structural rearrangements were more common. All the numerical abnormalities were monosomy 17, unbalanced translocations were much more frequent than balanced ones.