Jumping translocations: Short telomeres or pathogenic TP53 variants as underlying mechanism in acute myeloid leukemia and myelodysplastic syndrome?

1q jumping translocation as a biomarker in myeloid malignancy: frequently mutated genes associated with bad prognosis and low survival

1q jumping translocation (JT) is rare and its molecular profiles in myeloid malignancies are not well-known. This study evaluated gene mutations in 1q-JT cohorts (0.38%) from hematological malignant specimens that underwent genetic analysis at the Johns Hopkins Hospital (n = 11,908) and the MD Anderson Cancer Center. 1q-JT had frequent mutations in eleven genes, most of which are associated with worse prognosis. BCOR mutations significantly co-occurred with others. Patients tended to have mutations in DNA-repair, spliceosome, and epigenetic modification pathways, though genes utilized within each of these pathways were not randomly distributed. Multi-, albeit overlapping, pathway interruptions tended to manifest in mutations of two gene sets. One gene set consisted of SF3B1 (spliceosome) and TET2 (epigenetic modification), while the other consisted of STAG2 (DNA repair), SRSF2, U2AF (spliceosome), ASXL1, KMT2D (epigenetic modification), BCOR, and GATA2 (transcription factors). An "intermediate" JT-like rearrangement may represent an early sign of occurring 1q-JT. Treatments (hypomethylating agents) and unique structures of the short arms of acrocentric chromosomes may contribute to 1q-JT formation in myeloid malignancies. The median overall survival after identification of a JT was 10 months (95% confidence interval, 5-15 months). Our cohort represents the largest number of myeloid malignancies from multi-centers with before and after the 1q-JT event analyzed to date. Overall, this study identified specific molecular profiles that are associated with 1q-JT in myeloid malignancies. 1q-JT could serve as a poor prognosis biomarker in myeloid malignancies, which could be important in making well-informed clinical decisions and treatment strategies.

Jumping translocation of 3q21 in a patient with acute myeloid leukemia and poor clinical outcome

ABSTRACT

Jumping translocation (JT) is a cytogenetic event in which a donor chromosomal segment is translocated to two or more recipient chromosomes. We describe a case of a 75-year-old female patient diagnosed with acute myeloid leukemia (AML) with monocytic differentiation having acquired JT involving 3q21→3qter as a donor chromosomal segment with 12 different recipient chromosomes. Each abnormal clone had monosomy 7 and trisomy 8. Patients with JT have an adverse outcome, a high risk of disease progression, and an unfavorable prognosis. This is the sixth case of JT involving 3q21 and the first case having 12 different recipient chromosomes (15 chromosomal segments) along with monosomy 7 in all abnormal clones reported in the literature.

Role of telomere length in human carcinogenesis (Review)

Cancer is considered the most important clinical, social and economic issue regarding cause‑specific disability‑adjusted life years among all human pathologies. Exogenous, endogenous and individual factors, including genetic predisposition, participate in cancer triggering. Telomeres are specific DNA structures positioned at the end of chromosomes and consist of repetitive nucleotide sequences, which, together with shelterin proteins, facilitate the maintenance of chromosome stability, while protecting them from genomic erosion. Even though the connection between telomere status and carcinogenesis has been identified, the absence of a universal or even a cancer‑specific trend renders consent even more complex. It is indicative that both short and long telomere lengths have been associated with a high risk of cancer incidence. When evaluating risk associations between cancer and telomere length, a disparity appears to emerge. Even though shorter telomeres have been adopted as a marker of poorer health status and an older biological age, longer telomeres due to increased cell growth potential are associated with the acquirement of cancer‑initiating somatic mutations. Therefore, the present review aimed to comprehensively present the multifaceted pattern of telomere length and cancer incidence association.

Jumping Translocation in a Patient with Acute Leukemia and Fatal Evolution

Jumping translocations are uncommon cytogenetic abnormalities in which a segment of a donor chromosome, often 1q, is transferred to two or more receptor chromosomes. We describe the case of a 64-year-old man with a history of acute myeloid leukemia associated with myelodysplastic syndrome, who presented with a relapse of the leukemia and, concomitantly, with the appearance of a jumping translocation involving chromosome 1q. The patient had a poor clinical course without the possibility of performing targeted treatment, and he died 5 months after relapse. Jumping translocations are a reflection of chromosomal instability, and they could be related to epigenetic alterations such as pericentromeric chromatin hypomethylation, telomere shortening, or pathogenic variants of the TP53 gene. The existing data suggests a poor clinical outcome, a high risk of disease progression, and an unfavorable prognosis. More molecular studies are required to gain an in-depth understanding of the genetic mechanism underlying these alterations and their clinical significance and to be able to apply an optimal treatment to patients.