Three cases of near-tetraploid acute myeloid leukemias originating in pluripotent myeloid progenitors

The prognostic implications of tetraploidy/near-Tetraploidy in acute myeloid leukemia: a case series and systematic review of the literature

The prognostic significance and optimal management of tetraploidy/near-tetraploidy acute myeloid leukemia (T/NT AML) remains unclear given its limited data. This is especially true after factoring in additional chromosomal alterations, which carry their own prognostic weight. Here, we analyze 128 cases of T/NT in AML from the literature along with two additional cases, which is the largest review of this subject to date. Based on our retrospective analysis, we found that regardless of the risk status attributed to cytogenetics, the prognosis of tetraploid or near-tetraploid AML is dismal and should be incorporated within the unfavorable risk group. Complete remission is paramount to survival in this population. Specific induction protocols for high-risk AML appear to have higher rates of complete remission in the T/NT AML population. Moreover, longer overall survival can be achieved with chemotherapy followed by allogeneic stem cell transplantation at first complete remission.

Identification of chromosomal abnormalities and genomic features in near-triploidy/tetraploidy-acute leukemia by fluorescence in situ hybridization

Background

Near-triploidy/tetraploidy is rarely found in acute leukemia. Only limited data are available to characterize this condition, and it remains largely unknown.

Patients and methods

In our study, we performed karyotype analysis on 1,031 patients diagnosed with acute leukemia from 2006 to 2018. A total of 10 patients of near-triploidy/tetraploidy karyotype were enrolled. Two cases of near-triploidy (66-79 chromosomes) and eight cases of near-tetraploidy (84-100 chromosomes) were identified. Bone marrow samples of these 10 patients were analyzed by fluorescence in situ hybridization with 19 commercially available probes that detected a small portion of gene alterations and large regions of chromosome amplifications.

Results

Of the six patients with acute myelocytic leukemia, we detected three cases of double t(8;21)(q22;q22) that have not been previously reported, and one of them demonstrated ins(21;8) (q22;q24q22). We also describe a novel pediatric case carrying double t(15;17)(q22;q21) and receiving targeted treatment with all-trans retinoic acid therapy. To date, this case has responded well to the regimen and has shown continuous complete remission. All patients received chemotherapy. One of them received allogeneic hematopoietic stem cell transplant (HSCT) and survived for 22 months. Eight of the 10 patients died, and the median overall survival was 11 months.

Conclusion

Using fluorescence in situ hybridization, we identified the distinct complex karyotype of near-triploidy/tetraploidy and provided further prognostic information. Tetraploidy acute promyelocytic leukemia had favorable prognosis; thus, HSCT was not necessary. The case of insertion t(21;8)(q22;q24q22) in tetraploidy responded poorly to chemotherapy and achieved molecular remission with difficultly. Data from patients in this group indicated that near-triploidy/tetraploidy acute leukemia has poor prognosis and new therapy is urgently needed.

Tetraploidy/near-tetraploidy acute myeloid leukemia

A tetraploid/near tetraploid (T/NT) karyotype is a rare finding in acute myeloid leukemia (AML). Here we report 38 AML patients with a T/NT karyotype, including 26 men and 12 women with a median age of 65 years. T/NT karyotype was detected at initial diagnosis of AML in 16 patients, and acquired during the course of disease in 22 patients. All patients showed large blasts with frequent prominent nucleoli, cytoplasmic vacuoles and/or inclusions, nuclear irregularity and/or budding. Eleven patients had a non-complex and 27 had a complex T/NT karyotype; 21 patients also had pseudodiploid and/or triploid clones. After T/NT karyotype detection, 32 patients received chemotherapy and 10 also received stem cell transplant. After a median of 6.2 months follow-up, 32 patients died of disease or complications, 5 were alive with complete remission, and 1 alive with persistent AML. Median overall survival (OS) was 5 months. Patients with a non-complex T/NT karyotype had a significantly superior OS compared to those with a complex T/NT karyotype (10.7 vs. 3.4 months, p=0.0280). We conclude that T/NT karyotype in AML is often associated with distinctive morphologic features and conveys generally poor outcomes. Distinction of complex versus non-complex T/NT karyotype provides further prognostic information.

Prognostic significance of high hyperdiploid and triploid/tetraploid adult acute myeloid leukemia

To ascertain the clinical implications of high hyperdiploid (HH; 49-65 chromosomes) and triploid/tetraploid (TT; >65 chromosomes) adult acute myeloid leukemia (AML), all such cases were retrieved from the Swedish AML Registry. Of the 3,654 cytogenetically informative cases diagnosed between January 1997 and May 2014, 68 (1.9%) were HH (n = 50)/TT (n = 18). Patients with HH/TT were older than those with intermediate risk (IR) AML (median 71 years vs. 67 years; P = 0.042) and less often had de novo AML (63% vs. 79%; P = 0.004); no such differences were observed between HH/TT and complex karyotype (CK) AML. The overall survival (OS) was similar between patients with HH/TT and CK AML (median 0.9 years vs. 0.6 years; P = 0.082), whereas OS was significantly longer (median 1.6 years; P = 0.028) for IR AML. The OS was shorter for cases with HH than with TT (median 0.6 years vs. 1.4 years; P = 0.032) and for HH/TT AMLs with adverse abnormalities (median 0.8 years vs. 1.1 years; P = 0.044). In conclusion, HH/TT AML is associated with a poor outcome, but chromosome numbers >65 and absence of adverse aberrations seem to translate into a more favorable prognosis. Thus, HH/TT AMLs are clinically heterogeneous and should not automatically be grouped as high risk.

Clinicopathological analysis of near-tetraploidy/tetraploidy acute myeloid leukaemia

AIMS

Near-tetraploidy/tetraploidy (NT/T) is a rare cytogenetic alteration in acute myeloid leukaemia (AML). NT/T-AML is categorised as complex cytogenetics and therefore, presumed to have an unfavourable prognosis. Our aim is to further characterise the clinical, morphological, cytogenetic and prognostic features of NT/T-AML.

METHODS

We searched our cytogenetic laboratory database from 1991 to 2012 to reveal 13 cases of NT/T-AML. Each case was evaluated with regard to its demographics, morphology, immunophenotype and prognosis. Specific morphological features included blast size, irregularity of nuclear contours, cytoplasmic vacuoles, and presence and lineage of dysplasia.

RESULTS

Eleven men and two women had a median age of 68 years. Blasts were predominately large (11/13). Eight of 13 patients had AML with myelodysplasia-related changes. Sixty-nine per cent of patients achieved complete remission (CR). Median overall survival (OS) was 8.6 months. CR rate and median OS in cases with ≥ 5 cytogenetic abnormalities were 71% and 6 months, compared with 67% and 18.1 months in cases with <5 abnormalities.

CONCLUSIONS

NT/T-AML occurs in older males, exhibits large blast size and is associated with myelodysplasia. Unlike previously reported data, our study reveals an overall better prognosis in this older population with NT/T-AML than was expected for a complex karyotype AML. Cytogenetic complexity independent of ploidy status did not greatly affect the high CR rates, but did appear to be a better estimation of prognostic risk in terms of median OS.

Unusually long survival of a 67-year-old patient with near-tetraploid acute myeloid leukemia m0 without erythroblastic and megakaryocytic dysplasia

Patients with near-tetraploid acute myeloid leukemia (NT-AML) typically have poor survival. We present the case of a 67-year-old Caucasian male with NT-AML M0 who had an unusually long first complete remission of 51 months and an overall survival of 80 months. The only characteristic distinguishing him from other previously described patients with NT-AML was the absence of erythroblastic and/or megakaryocytic dysplasia (EMD) at diagnosis. Molecular-genetic testing for AML fusion transcripts associated with a favorable prognosis (PML/RARα,AML1/ETO, and CBFβ/MYH11) were negative, as were other prognostic markers like MLL-PTD,FLT3-ITD, or mutations of FLT3-D835,NPM1, or CEBPA. Expression studies of ERG,MN1, and EVI1 revealed overexpression of ERG only. The absence of EMD may be a useful prognostic/diagnostic feature of this new rare subtype of NT-AML.

Deficiency in myosin light-chain phosphorylation causes cytokinesis failure and multipolarity in cancer cells

Cancer cells often have unstable genomes and increased centrosome and chromosome numbers, which are an important part of malignant transformation in the most recent model of tumorigenesis. However, very little is known about divisional failures in cancer cells that may lead to chromosomal and centrosomal amplifications. In this study, we show that cancer cells often failed at cytokinesis because of decreased phosphorylation of the myosin regulatory light chain (MLC), a key regulatory component of cortical contraction during division. Reduced MLC phosphorylation was associated with high expression of myosin phosphatase and/or reduced myosin light-chain kinase levels. Furthermore, expression of phosphomimetic MLC largely prevented cytokinesis failure in the tested cancer cells. When myosin light-chain phosphorylation was restored to normal levels by phosphatase knockdown, multinucleation and multipolar mitosis were markedly reduced, resulting in enhanced genome stabilization. Furthermore, both overexpression of myosin phosphatase or inhibition of the myosin light-chain kinase in nonmalignant cells could recapitulate some of the mitotic defects of cancer cells, including multinucleation and multipolar spindles, indicating that these changes are sufficient to reproduce the cytokinesis failures we see in cancer cells. These results for the first time define the molecular defects leading to divisional failure in cancer cells.

[Near-tetraploidy acute myeloid leukemia with RUNX1-RUNX1T1 rearrangement due to cryptic t(8;21)]

Tetraploidy or near-tetraploidy is a rare cytogenetic abnormality found in AML, and is divided into primary and secondary forms. The secondary tetraploidy or near-tetraploidy found in AML is known to be specifically associated with t(8;21). In this case report, FISH analysis detected RUNX1-RUNX1T1 gene rearrangement in the absence of cytogenetic abnormality of t(8;21), which suggests the presence of unvailed t(8;21). This is the first case report of tetraploidy or near-tetraploidy AML with cryptic RUNX1/RUNX1T1 in Korea. Although the prognosis of tetraploidy or near- tetraploidy with t(8;21) is known to be poor, this patient shows a relatively good clinical course compared to other reported cases.

Enlarged and prominent nucleus may be indicative of tetraploidy: a laboratory study of a rare near-tetraploidy in a child patient with acute myelogenous leukemia AML-M4

Near-tetraploidy is a rare cytogenetic abnormality in myelocytic malignancies in children and its significance is unknown. To investigate the pathologic characteristics of a near-tetraploidy in a child with acute myelogenous leukemia (AML-M4), bone marrow smears were prepared for morphologic analysis. Bone marrow samples were collected at presentation for flow cytometry, prepared by short-term (24 h) unstimulated culture and R-banding for conventional cytogenetic assay. We have performed a multifactorial analysis of the laboratory test results. In this case, the chromosomal analysis (R-banding) demonstrated a near-tetraploidy. Combined with morphologic and immunophenotypic results, the diagnosis was established as acute myelogenous leukemia (AML-M4). Near-tetraploidy is an uncommon cytogenetic finding, and the experience of this case further emphasizes the importance of the laboratory diagnostic methods.

Tetraploidy/aneuploidy and stem cells in cancer promotion: The role of chromosome passenger proteins

While polyploidy, a state of having fully duplicated sets of chromosomes per cell, has been described in normally developing bone marrow megakaryocytes or as an adaptive response in other cell types, aneuploidy is never detected in normal cells. Tetraploidy or aneuploidy can be induced by several signals and it is highly prevalent in different forms of cancers, suggesting a role for this cell cycle state in promoting cellular transformation. Investigations suggested that loss of heterozygosity of cancer-related genes in stem cells might contribute to genetic instability in progeny cells and to subsequent cancer development. Deregulated expression of chromosome passenger proteins, such as Aurora kinases or Survivin, is a hallmark of various cancers, and experimentally induced changes in these regulators can promote tetraploidy or aneuploidy and loss of heterozygosity. Our studies described an induction of tetraploidy/aneuploidy by a stable form of Aurora-B, leading to acquisition of transformation properties. It is intriguing to speculate that in some cancers, tetraploidy/aneuploidy induced by deregulated expression of a mitotic regulator represents a primary event that leads to unbalanced expression of a cluster of crucial genes and to cellular transformation.

Secondary near-tetraploidy with double der(15)t(15;17) in acute promyelocytic leukemia in relapse

Tetraploidy or near-tetraploidy is a rare cytogenetic abnormality in acute myelocytic leukemia. We report here a case of acute promyelocytic leukemia that showed near-tetraploidy with double der(15)t(15;17) the leukemia relapsed. At diagnosis, cytogenetic analysis failed to reveal any karyotypic abnormality; however, a promyelocytic leukemia-retinoic acid receptor alpha (PML/RARA) fusion transcript of the bcr3-type was detected with reverse transcriptase-polymerase chain reaction analysis, and a single PML/RARA fusion signal was observed with fluorescence in situ hybridization analysis. At the first relapse, the majority of leukemic cells showed pseudodiploid karyotypes with der(15)t(15;17), as well as additional chromosomal abnormalities, and exhibited a single PML/RARA fusion signal. A small fraction of leukemic cells, however, showed near-tetraploid karyotypes with double der(15)t(15;17), as well as some additional chromosomal abnormalities in common with the pseudodiploid clones, and exhibited double PML/RARA fusion signals. At the second and third relapses, leukemic cells with near-tetraploidy and double PML/RARA fusion signals became predominant. The PML/RARA fusion transcript of the bcr3 type was also observed at each relapse. In addition, Southern blot analysis of the RARA gene at diagnosis and at the second relapse showed a common rearranged band. Notably, giant, bizarre, and hypogranular promyelocytes expressing CD2, CD34, and HLA-DR appeared at the first relapse and became predominant at the second and third relapses. These observations indicate that the APL cells with near-tetraploidy and double der(15)t(15;17) clonally evolved from the pseudodiploid leukemic cells and exhibited the bizarre morphology and aberrant surface immunophenotypes.

Hypocellular acute promyelocytic leukemia with a tetraploid clone characterized by two t(15;17)

We describe a case of hypocellular acute promyelocytic leukemia with a tetraploid clone characterized by two t(15;17). The large leukemia cells had a bizarre nuclear configuration and multiple Auer rods. A bone marrow biopsy specimen revealed a markedly hypocellular marrow (<10% cellularity) in the absence of myelofibrosis. Myelodysplastic features were not detected. Chromosome analysis of marrow cells revealed a karyotype of 92,XXYY,del(2)(q?),t(15;17)(q22;q21)x2. Interphase fluorescence in situ hybridization revealed that the marrow cells were composed of a tetraploid clone carrying double t(15;17) and normal diploid cells. The leukemia responded well to all-trans retinoic acid. We think that the tetraploidy could be caused by endoreduplication or endomitosis of the diploid clone with single t(15;17). The unique karyotype largely contributed to the cell morphology and marrow hypoplasia, while it may not have affected on the prognosis of the acute promyelocytic leukemia.

Tetraploid acute promyelocytic leukemia with double t(15;17) and PML/RARA rearrangements detected by fluorescence in situ hybridization analysis

Acute promyelocytic leukemia (APL) is characterized by a serious hemorrhagic syndrome, unique morphologic findings, and its response to retinoids. Tetraploidy is a very rare chromosomal abnormality in acute myelocytic leukemia. This report presents a unique case of APL with a tetraploid clone characterized by two t(15;17) without other chromosomal changes, as well as PML/RARA rearrangements confirmed fluorescence in situ hybridization. The morphology of the blast cells was that of the classic M3 subtype, but the mean blast size exceeded that of control APL cases with diploidy. A chromosomal study revealed a 92,XXXX,t(15;17)(q22;q21)x2 karyotype in all 20 metaphase spreads. Despite all-trans-retinoic acid (ATRA) treatment and chemotherapy, leukemic cells persisted in the blood, and the patient died of an intracranial hemorrhage on the 16th day after admission.

CD7+ near-tetraploid acute myeloblastic leukemia M2 with double t(8;21)(q22;q22) translocations and Aml1/ETO rearrangements detected by fluorescence in situ hybridization analysis

Near-tetraploidy is a rare cytogenetic abnormality observed in acute myeloblastic leukemia (AML). It was recently suggested that near-tetraploid AML may be associated specifically with t(8;21)(q22;q22). We report here a new case of near-tetraploid AML with double t(8;21)(q22;q22) translocations. A 61-year-old woman was admitted to our hospital because of high fever and pancytopenia. Her bone marrow was markedly hypercellular, with 72% giant and bizarre myeloblasts. These myeloblasts were positive for CD7, CD13, CD19, CD33, CD34, and HLA-DR but negative for CD2 and CD56. The patient's disease was diagnosed as the M2 subtype of AML (by French-American-British classification). Chromosome analysis revealed a karyotype of 45,X,-X, t(8;21) (q22;q22)[1]/90,XXX,-X,t(8;21)(q22;q22)x2,-9[7]/46,XX[12]. Fluorescence in situ hybridization (FISH) analysis with an AML1/ ETO probe detected 4 fusion signals on 2 der(8)t(8;21) and 2 der(21)t(8;21) in near-tetraploid cells. Reverse transcription-polymerase chain reaction analysis revealed the presence of the AML1/ETO fusion transcript. These findings suggested that near-tetraploidy may be a secondary genetic change originating from a diploid clone with t(8;21) and that 2 AML1/ETO fusion genes are generated on the der(8)t(8;21) in near-tetraploid clones. Consideration of the other reported cases suggests that the immunophenotypes of near-tetraploid AML with double t(8;21) are heterogenous, but it is possible that t(8;21)-AML with expression of CD2 or CD7 may be associated with a secondary clonal evolution to near-tetraploidy.

Acute myeloid leukaemia M0: haematological, immunophenotypic and cytogenetic characteristics and their prognostic significance: an analysis in 241 patients

Haematological, immunophenotypic and cytogenetic characteristics were analysed in 241 patients with acute myeloid leukaemia (AML) M0, including 58 children. Children < 3 years and adults between 60 and 70 years of age were most frequently affected. Immunophenotyping showed a heterogeneous phenotype. Anti-myeloperoxidase was positive in about half of the patients. Cytogenetic data were available from 129 (54%) patients. A normal karyotype was found in only 24%. Most of the abnormalities were unbalanced and the chromosomes 5, 7, 8 and 11 were the most frequently affected. Survival data were available from 152 treated patients (63%). The median overall survival for all patients was 10 months, 20 months for children (n = 36), 10 months for the young adult group (n = 50) and 7 months for the elderly patients (n = 66) (P = 0.09). Karyotype was not a prognostic factor influencing survival. AML M0 shows the immunological characteristics of early progenitor cells, but the expression of the different markers and cytogenetic abnormalities is heterogeneous. The prognosis is poor compared with other de novo AML and similar to that of AML with multilineage dysplasia or AML following myelodysplastic syndromes.