Tetrasomy 8 detected by interphase cytogenetics in a child with acute lymphocytic leukemia

Tetrasomy 8 in a patient with acute monoblastic leukemia

Trisomy 8 is one of the most frequent numerical chromosomal abnormalities observed in hematological malignancies, whereas tetrasomy 8 is a clonal aberration seen mainly in myeloid disorders such as acute myelod leukemia (AML) and myelodysplastic syndromes. In contrast to trisomy 8, tetrasomy 8 is a rare chromosomal aberration, in that only 17 reported AML cases with isolated tetrasomy 8 have been documented. Interestingly, the majority of reported cases were associated with monocytic-lineage leukemias. According to recent reports, tetrasomy 8 is regarded as a poor prognostic factor, and most patients having this abnormality relapsed and died within 1 yr. Here, we report a patient with acute monoblastic leukemia having tetrasomy 8 and a very aggressive disease course.

Acute myelogenous leukemia with tetrasomy 8 is a disease with a poor prognosis

Tetrasomy 8 is an extremely rare chromosome abnormality, one that has been reported in only a few cases with myeloid malignancies. The majority of reported cases consist of acute myelogenous leukemias (AML) of monocytic lineage. In slightly more than half of the patients, tetrasomy 8 was the single cytogenetic abnormality. Fluorescence in situ hybridization revealed tetrasomy 8 and trisomy 8 concurrently in all but one of the bone marrow samples. The clonal relationship between trisomy 8 and tetrasomy 8 in these cases remains to be clarified. Patients with tetrasomy 8 have a poor prognosis, and only 1 out of 33 patients was free of disease 3 years after autologous bone marrow transplantation. Here, we report the case of a 25-year-old female patient with monocytic leukemia and tetrasomy 8.

Tetrasomy 8 as a primary chromosomal abnormality in a child with acute megakaryoblastic leukemia

Tetrasomy 8 is a relatively rare chromosomal abnormality in hematological disorders, and is mostly associated with myeloid malignancies and poor prognosis. In a number of cases, tetrasomy 8 has been reported as an accompanying anomaly with other chromosomal changes. In this report, we describe a 14-year-old girl with acute megakaryoblastic leukemia associated with tetrasomy 8 (primary) and trisomy 6, 19 and 20. She died 6 months after diagnosis, suggesting a relatively poor prognosis for AML with tetrasomy 8. To the best of our knowledge, this is the first report of a tetrasomy 8 abnormality associated with subtype FAB M7. Interestingly, this abnormality has not been previously reported in childhood AML patients.

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.

Clonal evolution from trisomy into tetrasomy of chromosome 8 associated with the development of acute myeloid leukemia from myelodysplastic syndrome

Tetrasomy 8, though rare, is usually associated with trisomy 8, a far more common chromosomal abnormality in acute myeloid leukemia (AML). Yet the clonal relationship between trisomy 8 and tetrasomy 8 in the cases with these chromosomal abnormalities has been unclear. Here, we report a case of a 17-year-old male, diagnosed as having a myelodysplastic syndrome (MDS). Chromosome analysis showed the presence of trisomy 8. Five years later, he developed overt AML exhibiting tetrasomy 8 only. After chemotherapy, the blast cells in the bone marrow decreased to 3.4%, and the karyotype showed trisomy 8 alone. Fluorescence in situ hybridization using a probe specific for chromosome 8 showed that the percentages of cells exhibiting 2/ 3 /4 signals were 7.8/89.2/2.0 at the MDS stage, 20.5/36.1/41.0 when overt AML developed and 24.0/72.1/2.4 after chemotherapy. These results suggested that tetrasomy 8 is derived from the AML clone, possibly evolved from the MDS clone with trisomy 8. To our knowledge, this is the first detailed case report of clonal evolution from trisomy 8 into tetrasomy 8 associated with the development of AML from MDS.

Characterization of genetic instability in radiation- and benzene-induced murine acute leukemia

This study, using the CBA/Ca mouse as a model, compares genetic lesions associated with radiation- and benzene-induced acute leukemias. Specific types of leukemia included in the analyses are radiation-induced acute myeloid leukemia (ML), and benzene-induced lymphoblastic leukemias, lymphomas, or mix-lineage leukemias. These leukemias have histopathological characteristics similar to those seen in human acute leukemias. G-band cytogenetic analysis showed that specific deletions involving regions D-E of one copy of mouse chromosome 2 [del(2)(D-E)] were frequently associated in both radiation- and benzene-induced acute leukemias. In addition, translocations of chr2(D-E) were also observed in some cases. These results suggest an important role of chr2 (D-E) deletions and translocations in the development of radiation- and benzene-induced murine acute leukemias. Fluorescence in situ hybridization with DNA probes specific for 2(D-E), constructed in our laboratory by means of chromosomal microdissection and PCR amplification, also demonstrate 2(D-E) deletions and/or translocations in these leukemic cells. Aneuploidy of chromosomes 3, 15, 16, and Y were also frequently detected in benzene-induced leukemic cells with or without lesions on chr2. These cytogenetic findings support the previous observations that metabolites of benzene lead to spindle-fiber disruption or abnormal cytokinesis in exposed animals. In summary, genetic instabilities observed in leukemic cells isolated from mice that had developed leukemia after exposure to radiation or benzene are syntenic with those frequently detected in patients with myelodysplastic syndrome, acute ML, and acute lymphoblastic leukemia. Thus, the CBA/Ca mouse has several characteristics that make it an excellent model for the study of radiation or benzene leukemogenesis in humans.

Isolated tetrasomy 8 in minimally differentiated acute myeloid leukemia (AML-M0)

Tetrasomy 8 as a sole anomaly in hematological disorders is relatively rare. To the best of our knowledge, only 19 such cases have been described in the literature to date. Of them, acute myeloid leukemia (AML) in 13 (M1, one; M2, three; M4, one; M5, eight), acute lymphoblastic leukemia(ALL) in one, myelodysplastic syndrome(MDS) in 3, polycythemia vera(PV) and myelofibrosis(MF), one case each. Their median survival was 20 weeks. Here, we report the first case of a 29-year-old man with minimally differentiated AML (AML-M0) displaying a tetrasomy 8 clone. Immunophenotyping showed positivity with CD33, CD34 and intracellular MPO, but all lymphoid markers tested were negative. Conventional cytogenetics of bone marrow cells showed 84.9% of metaphases with tetrasomy 8 in addition to 15.1% with normal diploidy. However, Fluorescence in situ hybridization(FISH) using a centromeric probe specific for chromosome 8 revealed trisomy 8 in 14.2% of interphase nuclei besides tetrasomy 8 in 82.4%. The patient died four weeks after diagnosis without therapy. In conclusion, these findings suggest that tetrasomy 8 is associated with a heterogeneous group of myeloid disorders and heralds a bad prognosis. It may be a consequence of clonal evolution of trisomy 8.