17q21→17qter jumping translocations in a 13-year-old girl with RUNX1–RUNX1T1- positive acute myeloid leukemia

Summary

Introduction

Jumping chromosomal translocation (JT) is a rare cytogenetic phenomenon, meaning a translocation of the same segment of a donor chromosome to various recipient chromosomes, creating multiple related clones in an individual. The JTs have been described as a constitutional abnormality in solid neoplasms and, rarely, in various hematological malignancies including acute myeloid leukemia (AML), acute lymphoblastic leukemia, primary myelofibrosis, chronic myeloid leukemia, lymphomas, and multiple myeloma [1, 2]. In these patients, JTs occurred as secondary genetic events associated with disease progression. They are also detectable in secondary AML evolving from a preceding myeloproliferative neoplasm or myelodysplastic syndrome, or in relapsing acute leukemia.

JTs proved to be common at the elderly age.

Patient and Methods

We have reported a rare case of JT occurring in a 13-year-old girl with RUNX1–RUNX1T1-positive AML and WT1+ hyperexpression. JTs were revealed in bone marrow blast cells examined at the time of first relapse of AML that was completely resistant to previous chemotherapy. Conventional cytogenetics findings were confirmed by fluorescence in situ hybridization (FISH). To assign the chromosomal segments involved in JTs, multicolor FISH approach was chosen (MetaSystems, Germany). Cytogenetic analysis revealed JTs with chromosomal segments 17q21-17qter translocated to the pericentromeric regions of chromosomes 13,14,15 and to the 1p36 and 2q37regions. The patient was transplanted from haploidentical donor, but died after leukemia progression at day +40. (Fig. 1, 2, 3). Conclusion. Jumping translocations form a heterogeneous group of rare genetic events which seem to involve random chromosomal segments and may reflect a general chromosomal instability of the malignant cells. However, precise analysis of chromosomal breakpoints involved in JTs on a large series of patients helps to understand their mechanism and connection with pathogenesis together with the determination of clinical significance of these aberrations.

References

1. 1. P. McGrattan et al, Med Oncol 2010; 27 (3): 667-672
2. 2. K. Manola et al, Cancer Genet Cytogenet 2008; 187 (2): 85-94

Fig. 1, 2, 3. GTG---banded (A) and multicolor FISH (B) karyograms demonstrate reciprocal translocations t(8;21)(q22;q22) and jumping translocations producing the derivative chromosomes: der(1)t(1;17), der(2)t(2;17) and der(14)t(14;17). Karyotype: 45,X,---X, der(2)t(2;17)(q37;q21), t(8;21)(q22;q22)[7]/45,X,---X, der(14)t(14;17)(p13;q21), t(8;21)[6]/45,X,---X, der (1)t(1;17)(p36;q21), t(8;21)[4]/45,X,---X, der(13) t(13;17)(p13;q21), t(8;21)[2]/45,X,---X, der(15) t(15;17)(p13;q21), t(8;21)[2].

Keywords

Acute myeloid leukemia, jumping translocation, runx1– runx1t1, case report