PB2076 MOLECULAR CYTOGENETIC ANALYSIS OF CHROMOSOME 7 ABERRATIONS IN MYELOID DISEASES

• Published in: HemaSphere 2019-06, Vol.3 (S1), p.936-n/a
• Main Authors: Ransdorfova, S., Onderkova, M., Brezinova, J., Sarova, I., Valerianova, M., Svobodova, K., Lhotska, H., Pavlistova, L., Lizcova, L., Michalova, K., Zemanova, Z., Jonasova, A., Stopka, T., Cermak, J.
• Format: Article
• Language: English
• ISSN: 2572-9241; 2572-9241
• DOI: 10.1097/01.HS9.0000566788.92867.0c

Background: Complete or partial loss of chromosome 7 is a recurrent chromosomal aberration frequently found in myeloid disorders such as myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). This finding is an important prognostic indicator associated with poor response to the treatment and faster disease progression. Aims: (1) to determine the breakpoints on the long and short arm of chromosome 7 using FISH with locus‐specific probes; (2) to specify the frequency of these rearrangement; and (3) to evaluate overall survival [OS] of patients with chromosome 7 alteration. Methods: Diagnostic bone‐marrow samples of 46 adults with AML/MDS and with chromosome 7 aberration were examined. Karyotypes were analyzed using conventional and molecular cytogenetic techniques: FISH (Abbott, Kreatech), mFISH/mBAND (MetaSystems) and array CGH/SNP (Illumina, Agilent). Results: Monosomy 7 as a sole chromosomal abnormality was found in seven patients. Isolated deletion 7q was proved in one case only. In 38 cases, chromosome 7 aberrations were detected in combination with other changes (n = 16) or as a part of complex karyotype (n = 22). The most frequently altered regions on the long arm were identified in bands 7q22, 7q31 and 7q33‐7q36. In 17 patients (37%), deletion of the EZH2 tumor suppressor gene located in band 7q36.1 was found. The most frequently altered regions on the short arm were identified in bands 7p11‐p12. Rearrangements of 7p were always associated with other chromosomal alterations, the isolated 7p aberration was not proved. In 14 patients (30%), structural aberrations of both short and long arm 7p/7q were detected. In two cases, acquisition of additional clonal aberrations was observed during the disease. OS of the whole group was 6.45 months. Summary/Conclusion: In our cohort, the rearrangement of 7p as a sole aberration was not observed. A large heterogeneity of breakpoints was confirmed on the long arm 7q. High instability of chromosome 7 together with other chromosomal changes represent a marker of poor prognosis and is associated with rapid disease progression. In patients with myeloid malignancies, early detection of 7p/7q aberrations is important to precise prognostication and treatment decision. Supported by MH CZ‐DRO (IHBT, 00023736), RVO‐VFN64165, GACR P302/12/G157, Progres Q28/LF1.