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Turkish Journal of Medical Sciences

Abstract

Background/aim: Chronic myeloid leukemia (CML) is characterized by the Philadelphia chromosome (Ph), which occurs as a result of t(9;22). In 5%–10% of CML cases, variant t(9;22)s are observed. Additionally, while t(9;22) is formed, deletions can be observed in chromosomes 9 and 22. These deletions are observed more frequently in variant t(9;22). There is conflicting information in the literature about the prognostic effects of variant t(9;22) and deletions of 9q and 22q. There is also limited information about the frequency and breakpoints of other chromosomes involved in the variant t(9;22). Signal patterns other than the classical signal pattern of FISH analysis indicate deletions and variant translocations. In this study, we aimed to investigate the clinical significance of nonclassical FISH signal patterns and to determine the frequency of variant translocations.

Materials and methods: Bone marrow samples from 231 newly diagnosed CML patients were analyzed by conventional cytogenetics and FISH.

Results: As a result of FISH analysis, nonclassical FISH signal patterns were detected in 49/231 cases, and variant t(9;22) was detected in seven cases by conventional cytogenetics. It was determined that chromosomes 1, 3, 5, 7, 8, and 21 were involved in variant t(9;22). When cases with classical and nonclassical signal patterns were compared in terms of 6th- and 12th-month treatment responses, survival times, and treatment changes, it was found that cases with classical signal patterns had significantly higher treatment responses at the 6th month (p < 0.001).

Conclusion: Because variant translocations are extremely rare and involve many different chromosomal breaks, a large number of cases are needed to clearly understand their prognostic implications. Due to the limitations of conventional cytogenetic analyses, it should be considered in patient follow-up that nonclassical FISH signal patterns indicating deletions and/or variant translocations may cause a delay in obtaining a complete cytogenetic response at the 6th month.

Author ORCID Identifier

SEVGİ IŞIK: 0000-0003-0243-784X

OĞUZ ÇİLİNGİR: 0000-0003-1984-1494

GÜLÇİN GÜNDEN: 0000-0003-1707-1764

FİLİZ YAVAŞOĞLU: 0000-0002-4017-4668

HÜLYA ÖZEN: 0000-0003-4144-3732

MERT BURAK RAŞAN: 0000-0002-1418-8732

BEYHAN DURAK ARAS: 0000-0003-1881-1912

DOI

10.55730/1300-0144.6171

Keywords

22), Chronic myeloid leukemia, conventional cytogenetics, fluorescence in situ hybridization, variant t(9

First Page

377

Last Page

385

Publisher

The Scientific and Technological Research Council of Türkiye (TÜBİTAK)

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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