Chromosome 8 tetrasomies and pentasomies--a clonal abnormality closely associated with acute monocytic leukaemia

Extramedullary relapse of AML with t(9;11)(p22;q23) associated with clonal evolution from trisomy 8 into tetrasomy 8

This report describes a patient with extramedullary relapse of acute myeloid leukemia (AML) without involving bone marrow. A 57-year-old man was diagnosed as having acute monoblastic leukemia with t(9;11)(p22;q23) and trisomy 8. Ten months after achieving complete response (CR) with chemotherapy, masses developed in his left forearm and in the back of his thigh, preceded by enigmatic peripheral neurological symptoms. Aspiration from the forearm showed leukemic relapse, and fluorescence in situ hybridization (FISH) revealed that the majority of the cells had 11q23 anomaly and tetrasomy 8. Bone marrow or meningeal relapse was not observed. To our knowledge, this is the first case report of clonal evolution associated with the development of myeloid sarcoma as a relapse in AML.

Chromosome 8 pentasomy with partial tandem duplication of 11q23 in a case of de novo acute myeloid leukemia

Polysomy 8 is a rare abnormality, one that has been reported as associated with secondary evolution, monocytic differentiation, or poor prognosis in myeloid neoplasm. In contrast to tetrasomy 8, which is most commonly observed, pentasomy 8 is a minority component of polysomy 8. To date, only three cases of pentasomy 8 accompanied with 11q23 rearrangement have been reported. Reported here is a novel case of pentasomy 8 with partial tandem duplication of 11q23 in de novo acute myeloid leukemia. The findings contribute to understanding of the relation between the two abnormalities, which have their own individual leukemogenic potencies.

Redefining monosomy 5 by molecular cytogenetics in 23 patients with MDS/AML

Deletion of the long arm of chromosome 5 [del(5q)] or loss of a whole chromosome 5 (-5) is a common finding, arising de novo in 10% of patients with myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML) and in 40% of patients with therapy-related MDS or AML. We investigated by molecular cytogenetics 23 MDS/AML patients for whom conventional cytogenetics detected a monosomy 5. Monosomy 5 was redefined as unbalanced or balanced translocation and ring of chromosome 5. Loss of 5q material was identified in all 23 patients, but one. One copy of EGR1(5q31) or CSF1R(5q33-34) genes was lost in 22 of the 23 patients. Chromosome 5p material was a constant chromosomal component of derivative chromosomes or rings in all patients, but one. Sequential fluorescent in situ hybridization studies with whole chromosome paints and region-specific probes, used as a complement to conventional cytogenetic analysis, allow a better interpretation of karyotypes in MDS/AML patients.

Polysomy 8 defines a clinico-cytogenetic entity representing a subset of myeloid hematologic malignancies associated with a poor prognosis: report on a cohort of 12 patients and review of 105 published cases

Tetrasomy, pentasomy, and hexasomy 8 (polysomy 8) are relatively rare compared to trisomy 8. Here we report on a series of 12 patients with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or myeloproliferative disorder (MPD) associated with polysomy 8 as detected by conventional cytogenetics and fluorescence in situ hybridization (FISH). In an attempt to better characterize the clinical and hematological profile of this cytogenetic entity, our data were combined with those of 105 published patients. Tetrasomy 8 was the most common presentation of polysomy 8. In 60.7% of patients, polysomy 8 occurred as part of complex changes (16.2% with 11q23 rearrangements). No cryptic MLL rearrangements were found in cases in which polysomy 8 was the only karyotypic change. Our study demonstrates the existence of a polysomy 8 syndrome, which represents a subtype of AML, MDS, and MPD characterized by a high incidence of secondary diseases, myelomonocytic or monocytic involvement in AML and poor overall survival (6 months). Age significantly reduced median survival, but associated cytogenetic abnormalities did not modify it. Cytogenetic results further demonstrate an in vitro preferential growth of the cells with a high level of aneuploidy suggesting a selective advantage for polysomy 8 cells.

[Chromosomal abnormalities in acute myeloid leukaemias]

Cytogenetic studies of acute myeloid leukaemias reveal non-random chromosomal abnormalities in 50-70% of karyotypes. Some are correlated with morphological and immunological parameters and constitute a prognostic factor independent of the other factors of risk: favourable for acute leukaemias myeloid with translocations t(8;21), t(15;17) and inversion or translocation of the chromosome 16, inv(16)/t(16;16), poor with deletion of the long arm of chromosome 5 del(5q), rearrangement of the 11q23 region and complex karyotypes. The distribution of the anomalies depends on the age: 11q23 and t(8;21) more frequent for the child, del(5q) and complex anomalies more frequent for the adult. The karyotypes are essential for the diagnosis, the follow-up of the patients and the evaluation of the relapse. It plays a fundamental part in the detection of new genes and their partners implied in the leucemogenese. The knowledge of their function is essential to open new therapeutic ways.

Pentasomy 8q in therapy-related myelodysplastic syndrome due to cyclophosphamide therapy for fibrosing alveolitis

Trisomy 8/8q is a common cytogenetic event in myelocytic malignancies, ranging from myelodysplastic syndrome (MDS) to acute myelocytic leukemia (AML) to blastic transformation of chronic myelocytic leukemia. Isochromosome 8q results in the same gene dosage effect. Duplication of i(8q), resulting in pentasomy 8q, has been reported only in two cases of AML. A patient with fibrosing alveolitis on prolonged cyclophosphamide treatment developed therapy-related MDS. Karyotyping, FISH, and CGH analysis showed a duplicated i(8q) among other complex abnormalities. The clinical features of 11 cases of myelocytic leukemia with pentasomy and hexasomy 8/8q were summarized. Compared with trisomy and tetrasomy 8, significant features included reduced median survival (90 days), treatment refractoriness (even with transplantation), monocytic differentiation, trilineage dysplasia, and radiation or toxin exposure. Increasing copy numbers of chromosome 8/8q may therefore be a marker of advanced leukemic evolution, exposure to toxins, underlying myelodysplasia, and an overall poor prognosis.

Tetrasomy 8 is associated with a major cellular proliferative advantage and a poor prognosis. two cases of myeloid hematologic disorders and review of the literature

We report two cases of acute myeloid leukemia (AML) with tetrasomy 8 detected in patients' bone marrow samples using chromosome GTG-banding, fluorescence in situ hybridization (FISH) and primed in situ labeling (PRINS) techniques. Case 1 was a myelodysplastic syndrome (MDS) in transition to AML-M4 and case 2 was an AML-M2. In case 1, the tetrasomy 8 was found in 40% of metaphase cells and constituted the only chromosome abnormality. In case 2, it was accompanied by a double Ph, trisomy 18 and disomy Y and was found in 68% of metaphase cells. However, FISH and PRINS techniques revealed the coexistence of tetrasomy 8 and trisomy 8 in interphase nuclei of both cases. When the proportion of cells with tetrasomy 8 was compared between metaphases and interphase nuclei, it showed a much higher percentage of cells with tetrasomy 8 in metaphases than in interphase nuclei. Moreover, in case 2, although multi-PRINS and FISH-PRINS techniques showed other populations of interphase nuclei with different combinations of chromosome anomalies with respect to the copy numbers for chromosomes 8, 18, Y and Ph, only cells that contained either a single Ph or tetrasomy 8 plus trisomy 18, disomy Y, and double Ph could be seen in metaphases. This strongly suggests that tetrasomy 8 confers a higher proliferative advantage to cells. Our cases also show that the tetrasomy 8 is associated with a poor prognosis.

Tetrasomy 8 evolving into a segmental triplication 8q in a case of acute monocytic leukemia

We report a case of AML-M5 with tetrasomy 8 that evolved within a 7-month period to a segmental triplication 8q. Other numerical abnormalities in the initial diagnosis were not found at the relapse; however, a chromosome 1 structural abnormality was maintained, proving the clonal evolution from tetrasomy 8 to a segmental triplication of the long arm of 8. This strongly suggests that there is a functional and selective advantage for duplications and triplications of 8q in these patients.