Extra copy of 20q deletion, acute myelomonocytic leukemia (M4) and Niemann-Pick disease

A 59-year-old hypertensive white male was diagnosed with acute myelogenous leukemia (AML), M4. A bone marrow aspirate showed a karyotype of 46,XY,del(20)(q11.2q13.3)[12]/ 47,XY,del(20)(q11.2q13.3)x2[8]. The majority of cases with 20q deletion are associated with myeloid disorders; however, an extra copy of the 20q deletion has rarely been reported. The patient expired seven days after admission to the hospital. At autopsy hepatosplenomegaly was present. Many foamy macrophages with bubbling cytoplasm in the spleen, liver, bone marrow and lymph nodes were suggestive of Niemann-Pick disease, type E. AML has not previously been reported with Niemann-Pick disease.     

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.     

Complex cytogenetic abnormalities in a patient with chronic myeloid leukemia: a case report

A case of multiple chromosome aberrations in a patient with CML (chronic myeloid leukemia) in the accelerated phase was described. Cytogenetic and molecular genetic studies revealed the presence of a t(9; 22)(q34; q11) translocation and some additional abnormalities such as t(1; 2)(p36; p21), del(6)(q21), +del(8)(q22), del(18)(q21), and +der(22), part of which is not typical for this kind of pathology. The correlation between the obtained data and the data presented in different publications is considered. A probable connection of the detected changes with previously received treatment and a possible effect of these changes on CML progression are discussed.     

Translocation (3;21)(q26;q22) in secondary leukemia. Report of two cases and literature review.

The authors report two cases of secondary myelodysplasia and acute myeloid leukemia with t(3;21)(q26.3;q22) as the only cytogenetic abnormality in neoplastic bone marrow. This translocation was identified as a rare, recurring, non-random aberration in chronic myeloid leukemia less than five years ago and in secondary acute myeloid leukemia and myelodysplasia in 1990. The known and suspected cases in the literature are reviewed.     

Cholesterol regulates VEGFR-1 (FLT-1) expression and signaling in acute leukemia cells

VEGF receptors 1 (FLT-1) and 2 (KDR) are expressed on subsets of acute myeloid leukemia (AML) and acute lymphoid leukemia cells, in which they induce cell survival, proliferation, and migration. However, little is known about possible cofactors that regulate VEGF receptor expression and activation on leukemia cells. Here we show that cholesterol accumulates in leukemia-rich sites within bone marrow of xenotransplanted severe combined immunodeficient (SCID) mice. Therefore, we hypothesized that cholesterol-rich domains might regulate FLT-1 signaling and chemotaxis of acute leukemias. We then showed that FLT-1 accumulates in discrete cholesterol-rich membrane domains where it associates with caveolin-1 and that placenta growth factor (PlGF)/VEGF stimulation promotes FLT-1 localization in such cholesterol-rich domains. Accordingly, FLT-1 localization and its phosphorylation are abrogated by methyl-β-cyclodextrin (MβCD), which removes cellular cholesterol, and by nystatin, an inhibitor of lipid-raft endocytosis. Mechanistically, cholesterol increases FLT-1 expression and promotes PlGF/VEGF-induced leukemia cells viability and also induces VEGF production by the leukemia cells in vitro. Taken together, we conclude that cholesterol regulates VEGF:VEGFR-1 signaling on subsets of acute leukemias, modulating cell migration, and viability, which may be crucial for disease progression. Finally, we provide evidence obtained from human AML samples that primary leukemia cells accumulate significantly more cholesterol than do normal cells and that cholesterol accumulation correlates with disease aggressiveness.     

Burkitt-type ALL with variant t(2;8) and complex additional rearrangements at diagnosis

We describe a case of Burkitt-type acute lymphoblastic leukemia (L3 according to the classification FAB) with a variant t(2;8)(p12;q24) and additional chromosomal abnormalities at diagnosis. The karyotype was 47,X,Xq+,t(2;8)(p12;q24),7q+,12p+,+mar. The literature on chromosome rearrangements associated with t(2;8) in L3 leukemias has been reviewed.     

Case report of isochromosome 17q in acute myeloid leukemia with myelodysplasia-related changes after treatment with a hypomethylating agent

Isochromosome 17q is a relatively common karyotypic abnormality in medulloblastoma, gastric, bladder, and breast cancers. In myeloid disorders, it is observed during disease progression and evolution to acute myeloid leukemia in Philadelphia-positive chronic myeloid leukemia. It has been reported in rare cases of myelodysplastic syndrome, with an incidence of 0.4-1.57%. Two new agents have been approved for treatment of myelodysplastic syndrome/chronic myelomonocytic leukemia. These are the hypomethylating agents, 5-azacytidine and decitabine, recommended by consensus guidelines for high-risk myelodysplastic syndrome patients not eligible for hematopoietic stem cell transplantation. We present a case of chronic myelomonocytic leukemia with normal cytogenetics at diagnosis treated with decitabine (with good response); however, the patient evolved to acute myeloid leukemia with i(17q) shortly after suspending treatment. To the best of our knowledge, this is the first report of acute myeloid leukemia with myelodysplasia-related changes with i(17q) after the use of a hypomethylating agent.     

FISH studies on the telomeric regions of the T-cell acute lymphoblastic leukemia cell line CCRF-CEM

So far, the problem of an influence of translocations on the telomeres of the involved chromosomes has not been addressed yet in human cells. Therefore, the telomeres of a karyotypically rather well characterized T-cell acute lymphoblastic leukemia (T-ALL) cell line (CCRF-CEM) with several marker chromosomes were examined using peptide nucleic acid (PNA) telomere FISH probes to compare the telomere length of these markers with that of the chromosome arms of their origin. In addition, chromosome libraries, centromeric probes, and subtelomeric DNA probes were used to further define the marker chromosomes. Two markers could be newly defined and a concise karyotype of the cell line could be obtained by these detailed examinations: 42-47,X,-X,del(5) (q35?),t(5;15)(q14;q13.2),t(8;9)(p11;p24),del(9)(:p13-->qter)/inv(9)(pter-->p12::q21-->p12::q21-->qter),+13,+20,+der(22)(p+ [HSR?])[cp]. The relative telomere length of all chromosomes showed considerable interchromosomal, intercellular, and inter-passage variation. However, it could be shown, that in four different passages of the examined cell line the observed differences between relative telomere lengths of the markers and the chromosomes of their origin, with two exceptions (short arms of del/inv9 and der22), were not significant. On the other hand, because of its mentioned variability, telomere length alone is not sufficient to reliably define the derivation of markers.     

Expression of immunological markers on leukemic cells before and after cryopreservation and thawing

We have studied the effects of cryopreservation on the viability and on the expression of surface antigens of acute leukemia cells. Marrow samples were obtained at initial diagnosis from 89 patients with acute myeloid leukemia (AML), acute undifferentiated leukemia (AUL), and acute lymphoid leukemia (ALL). In AML, the mean viability was greater than 90% in the types M1, M4, and M5 of the French-American-British classification, 79% in M2, and 3% in M3 types. The viability was 74% in AUL. In ALL, the viability was 95% for pre-B leukemias, but only 2% in T-cell leukemias. The expression of myeloid antigens was studied before and after freezing and thawing using three monoclonal antibodies (NHL30.5, against poorly differentiated granulocytic leukemias, VIMC6 against differentiated granulocytic leukemias and granulocytes; and UCHM1 or CRIS-6, against monocytic leukemias and monocytes). The percentage of cells stained by NHL30.5 and UCHM1 or CRIS-6 was very similar before and after cryopreservation. For VIMC6, the mean staining after cryopreservation was 60% of the initial one. In pre-B ALL, the stainings by anti common ALL antigen before and after cryopreservation were also very similar. We conclude that leukemic cryopreserved cells are suitable for immunologic studies. The recovery is, however, very low in promyelocytic AML and T-cell ALL.     

Identification of a human gene (HCK) that encodes a protein-tyrosine kinase and is expressed in hemopoietic cells.

We have isolated cDNAs representing a previously unrecognized human gene that apparently encodes a protein-tyrosine kinase. We have designated the gene as HCK (hemopoietic cell kinase) because its expression is prominent in the lymphoid and myeloid lineages of hemopoiesis. Expression in granulocytic and monocytic leukemia cells increases after the cells have been induced to differentiate. The 57-kilodalton protein encoded by HCK resembles the product of the proto-oncogene c-src and is therefore likely to be a peripheral membrane protein. HCK is located on human chromosome 20 at bands q11-12, a region that is affected by interstitial deletions in some acute myeloid leukemias and myeloproliferative disorders. Our findings add to the diversity of protein-tyrosine kinases that may serve specialized functions in hemopoietic cells, and they raise the possibility that damage to HCK may contribute to the pathogenesis of some human leukemias.     

Flow cytometric DNA index and karyotype in childhood lymphoblastic leukemia.

Flow cytometric DNA-index (DI(FCM)) and karyotype were analysed in 82 consecutive children with acute lymphoblastic leukemia (ALL) during a 10 year period. A statistically significant correlation existed between modal chromosome number and DI(FCM) (p = 0.009). DI(FCM) could reliably identify leukemias with >51 chromosomes, whereas only three out of 12 cases with modal chromosome numbers between 47-51 were classified as aneuploid by DI(FCM). In the pseudodiploid group only one out of 20 leukemias had a DI(FCM) > 1.0. Five leukemias with a diploid karyotype showed an aneuploid DI(FCM) and in three patients the flow cytometric measurement revealed biclonality undetected by karyotyping. During treatment aneuploid clones could be detected by DI(FCM) in a substantial number of cases where the cytogenetic analysis was normal, and the opposite was also demonstrated in one case. DI(FCM) gave prognostic information, showing that cases with a DI > 1.12 (corresponding to 51 chromosomes) had a superior outcome with treatment protocols today in use.     

A novel t(4;16)(q25;q23.1) associated with EGF and ELOVL6 deregulation in acute myeloid leukemia

About 50% of acute myeloid leukemia (AML) patients show the occurrence of non-random chromosome rearrangements. Most of the recurrent karyotypic rearrangements in AML have been defined as distinct disease entities in the 2008 World Health Organization (WHO) classification. In this paper we report an AML case showing a novel t(4;16)(q25;q23.1) rearrangement causing the activation of epidermal growth factor (EGF) and elongation of long-chain fatty acids family member 6 (ELOVL6) genes, rather than the generation of a novel fusion gene.     

Acute promyelocytic leukemia with unusual karyotype

Acute myeloid leukemia (AML-M3) is associated with the translocation t(15;17)(q22;q12-21) which disrupts the retinoic acid receptor alpha (RARA) gene on chromosome 17 and the PML gene on chromosome 15. We report a two-year-old patient with AML-M3 without the usual translocation t(15;17). Cytogenetic studies demonstrated normal appearance of chromosome 15 while the abnormal 17 homologue was apparently a derivative 17, der(17)(17qter-cen-q21:), the rearrangement distinctly shows deletion at 17q21 band and the morphology corresponding to an iso chromosome i(17q-). This case report is a rare cytogenetic presentation of acute promyelocytic leukemia (APML).     

Novel insights into the pathogenesis of the Graffi murine leukemia retrovirus

The Graffi murine leukemia virus (MuLV) was isolated in 1954 by Arnold Graffi, who characterized it as a myeloid leukemia-inducing retrovirus. He and his team, however, soon observed the intriguing phenomenon of hematological diversification, which corresponded to a decrease of myeloid leukemias and an increase of other types of leukemias. Recently, we derived two different molecular clones corresponding to ecotropic nondefective genomes that were named GV-1.2 and GV-1.4. The induced leukemias were classified as myeloid based on morphological analysis of blood smears. In this study, we further characterized the two variants of the Graffi murine retrovirus, GV-1.2 and GV-1.4, in three different strains of mice. We show that the Graffi MuLV is a multipotent retrovirus capable of inducing both lymphoid (T- and B-cell) and nonlymphoid (myeloid, erythroid, megakaryocytic) leukemia. Many of these are very complex with concomitant expression of different hematopoietic lineages. Interestingly, a high percentage of megakaryocytic leukemias, a type of leukemia rarely observed with MuLVs, arise in the FVB/n strain of mice. The genetic backgrounds of the different strains of mice influence greatly the results. Furthermore, the enhancer region, different for GV-1.2 and GV-1.4, plays a pivotal role in the disease specificity: GV-1.2 induces more lymphoid leukemias, and GV-1.4 induces more nonlymphoid ones.     

Rearrangements of chromosome 9 in different hematological neoplasias

In the present article the frequency of anomalies in chromosome 9 among children with hematological neoplasias amounted to 25/112 in acute lymphoblastic leukemia (ALL), 10/83 in acute myeloid leukemia (AML), and 3/20 in myelodysplastic syndrome (MDS). In ALL, deletions are encountered more often than translocations. Deletions are found in both single anomalies and as an element in complex karyotypes. The rearrangements involve the bands 9q34 and 9q22 the most often. The translocation t(9;22)(q34; q11) is encountered in 7.1% of all cases of ALL. In AML, translocation are found more often than deletions. Structural rearrangements most often involved the long arm, at bands 9q22 and 9q34. Deletions, duplications, and translocations were recorded in MDS. No relationship with the initial hematological indicators, including blastosis, were found. The studies attest to different directions of the clinical prognosis in the course of acute leukemia (AL) where there are deletions. Multidrug resistance and the continuing progress of the disease in the course of chemotherapy is found in t(9;22)(q34; q11).     

Chromosomal rearrangements and their effects in spontaneous immortalization and transformation of rat embryo cells in vitro

G-banding analysis of LRec-1 and LRec-3, spontaneously immortalized cell lines from rat embryo fibroblast, revealed diploid karyotypes with specific clonal structural rearrangements of chromosomes 7 and 19 - del(7)(q11.2q22.1), t(7;19)(q11.1;q12) in malignant stage. Both clonal abnormalities of chromosomes 7 and 19 were also revealed in LRec-1k clone and LRec-1 sf cell line. Previous study of LRec-1 and LRec-3 cells showed the presence of karyotypes with pseudodiploid modal chromosome number, partial trisomy of chromosome 7 and same clonal structural rearrangements of chromosomes 7 and 19 in immortalized stage. In malignant stage, the trisomy 6 and new clonal structural rearrangements of chromosomes 1, 2, 11, 15, 18, 19 and of chromosomes 10, 20 were also found in LRec-1 sf and LRec-1 cells, accordingly. There were no new clonal structural chromosome rearrangements in LRec-1 k and LRec-3 cells. We compared locies of chromosomes involved in rearrangements with mapped genes on these chromosomes according to RATMAP. Supposedly these genes are involved in spontaneous immortalization of rat embryo fibroblast and malignant transformation of LRec-1 and LRec-3 cells and rearrangements of chromosomes 1, 2, 11, 15 and 18 facilitate expression of growth factors of LRec-1 sf cells.     

Growth of normal versus leukemic bone marrow cells in long term culture from acute lymphoblastic and myeloblastic leukemias

The ability of the in vitro long-term bone marrow culture (LTBMC) system to impair the survival of leukemic cells and to enhance the growth of normal progenitors has been studied. Bone marrow cells from 19 acute lymphoblastic leukemia (ALL) and 30 acute myeloid leukemia (AML) patients at diagnosis were grown in LTBMC for 4-10 weeks. In half of the cases the leukemic population declined down to undetectable levels and was replaced by putative normal hemopoietic precursors, both in ALL and in AML. In the remaining cases, leukemic cells persisted throughout the culture time and few if any normal hemopoietic cells were detected. These data led us to extend to the lymphoid compartment the previous observation of decreasing leukemic myeloid blasts in LTBMC. The potential of such cultures as an in vitro purging system for autologous bone marrow transplantation in selected poor-prognosis lymphoid malignancies should be explored, as has been done for acute and chronic myeloid leukemias.     

Loss-of-function mutation of the AF9/MLLT3 gene in a girl with neuromotor development delay, cerebellar ataxia, and epilepsy

The human AF9/MLLT3 gene is a common fusion partner for the MLL gene in translocations t(9;11)(p22;q23) associated with acute myeloid leukemia and acute lymphocytic leukemia. The exact function of the gene is still unknown, although a mouse knock-out model points to a role as a controller of embryo patterning. We report the case of a constitutional translocation t(4;9)(q35;p22) disrupting the AF9/MLLT3 gene in a girl with neuromotor development delay, cerebellar ataxia and epilepsy. Array-CGH analysis at 1 Mbase resolution did not reveal any additional deletions/duplications. We hypothesize a loss-of-function mutation of the AF9/MLLT3 gene, and a possible role for the FAT gene on chromosome 4, in the genesis of the proband’s severe neurological phenotype.     

Chronic myelogenous leukemia with translocations (3q-;9q+) and (17q-;22q+). Possible crucial cytogenetic events in the genesis of CML

Summary Two reciprocal translocations involving chromosomes 3, 9, 17, and 22 were found in a patient with seemingly Ph¹-negative chronic myelogenous leukemia (CML). The two translocations were t(3;9)(q21;q34) and t(17;22)(q21;q11); the breakage in chromosomes 9 and 22 apparently occurred at the same point as in the usual Ph¹ translocation, t(9;22)(q34;q11).From the present evidence and a review of the literature it appears that the breakage on both chromosomes 9 and 22 at the special regions and the separation of the fragments are present in practically all standard and variant Ph¹ translocations, even those in which the terminal region of the long arm of chromosome 9 (9q) does not seem to be involved in the rearrangement; however, a translocation between chromosomes 9 and 22 is not an obligatory result of the rearrangement, as seen in the present case. Thus, we postulate that the breakage on both chromosomes 9 and 22 at the special regions and separation of the fragments are the crucial cytogenetic events in the genesis of CML and stress the importance of paying careful attention to the terminal region of 9q, particularly when chromosome 9 does not seem to be involved in the rearrangement.This work was supported in part by grants (Nos. 401001 and 401071) from the Ministry of Education, Science and Culture of Japan     

FISH mapping of i(7q) in acute leukemias and myxoid liposarcoma reveals clustered breakpoints in 7p11.2: implications for formation and pathogenetic outcome of the idic(7)(p11.2)

Isochromosome 7q - i(7q) - is seen in a wide variety of hematologic malignancies and solid tumors, often as a secondary change to a characteristic primary translocation. Despite its high frequency, nothing is known about the formation and the pathogenetic outcome of this abnormality. To address these issues, we performed a detailed fluorescence in situ hybridization (FISH) investigation of four acute lymphoblastic leukemias, one acute myeloid leukemia, and two myxoid liposarcomas with i(7q). Using FISH with bacterial artificial chromosomes (BACs) mapping between 7p12.2 and 7q11.2, the breakpoints (BPs) in all seven cases were shown to cluster to an approximately 340 kb segment at 7p11.2, covered by the overlapping BAC probes RP11-760D2 and RP11-10F11. Thus, the i(7q) should formally be designated idic(7) (p11.2). In one of the cases, FISH with fosmids could narrow down the BP further to an 80-kb sequence delineated by G248P81983A10 and G248P8793H7. No known genes are located in the 340-kb BP cluster region, indicating that the idic(7)(p11.2) does not result in a fusion or deregulation of genes in this segment. The pathogenetically important outcome is thus likely to be an altered gene expression because of copy number changes. The clustering of breakpoints might be due to frequent intrachromosomal duplicons in the BP region.