Isochromosome of a deleted 20q: a rare but recurrent chromosome abnormality in myelodysplastic syndromes.

Interstitial deletion of the long arm of chromosome 20, as the sole abnormality, is commonly observed in myeloid malignancies, including myeloproliferative disorder, myelodysplastic syndrome, and acute myeloid leukemia. The breakpoints of the deletion are typically located in the region 20q11.2 approximately q13.3, although smaller deletions within this region have also been reported. We present here 4 patients with myelodysplastic syndrome with an isochromosome of the deleted long arm of chromosome 20: ider(20)(q10)del(20)(q11q13). Fluorescence in situ hybridization studies were performed on the bone marrow samples from these patients to prove the identity of this unusual chromosome abnormality.

Frequent expression of HAGE in presentation chronic myeloid leukaemias.

Cancer testis (CT) antigens provide attractive targets for cancer-specific immunotherapy. Although CT genes are expressed in some normal tissues, such as the testis and in some cases placenta, these immunologically protected sites lack MHC I expression and as such, do not present 'self' antigens to T cells. To date, CT genes have been shown to be expressed in a range of solid tumours, but rarely in haematological malignancies. We have extended previous studies to investigate the expression of a comprehensive range of CT genes (MAGE-A1, -A3, -A6, -A12, BAGE, GAGE, HAGE,LAGE-1, NY-ESO-1 and RAGE) for their expression in a cohort of acute and chronic myeloid leukaemia patient samples. CT expression was not detected in 20 normal bone marrow or peripheral blood stem cell samples. In acute myeloid leukaemia (AML) nine of the 26 (35%) samples analysed expressed one or more of the CT genes with six of the samples (23%) expressing HAGE. In chronic myeloid leukaemia (CML) 24 of 42 (57%) presentation chronic myeloid leukaemia (CML) patient samples expressed one or more CT antigen with 23 expressing HAGE. We have shown that HAGE is frequently expressed in CML, and to a lesser extent in AML patient samples. This is the first demonstration of HAGE gene expression in myeloid leukaemia patients and the frequent expression of HAGE at disease presentation opens up the possibility of early immunotherapeutic treatments.

Amplification or rearrangement of the beta-human chorionic gonadotrophin (beta-hCG)--human LH gene cluster is not responsible for the ectopic production of beta-hCG by bladder tumour cells.

The beta-subunit of human chorionic gonadotrophin (hCG) is coded on chromosome 19 by the beta-hCG-hLH gene cluster. Genomic DNA has been isolated from bladder tumour cell lines which ectopically express beta-hCG. The beta-hCG-hLH gene cluster was probed for possible rearrangement or amplification and cells karyotyped for chromosome 19 abnormalities. No rearrangement or amplification of the gene cluster and no consistent abnormalities of chromosome 19 were found. The expression of beta-hCG by bladder tumours is therefore likely to be the result of altered gene regulation and not a rearrangement or amplification of this gene cluster.

Translocation (9;17) a novel translocation in acute myeloid leukaemia.

We report a case of AML, acute myeloid leukaemia, with a novel translocation involving the short arms of chromosomes 9 and 17. The acute myeloid leukaemia was morphologically classified as FAB subtype M2. A prolonged remission was induced with chemotherapy, followed by a relapse which was associated with the finding of the same translocation.

Deletion of the acetylcholinesterase locus at 7q22 associated with myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML).

The genes for acetylcholinesterase (ACHE) and butyrylcholinesterase (BCHE) are located within regions subject to non-random chromosomal abnormalities in the myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML). Acetylcholinesterase is mapped to 7q22, within the critical deleted region presumed to contain a myeloid specific tumour suppressor gene. Butyrylcholinesterase is mapped to 3q26: abnormalities at this region are associated with sub-types of MDS and AML with thrombocytopenia, or with increased platelet counts. Both ACHE and BCHE have been implicated as playing a role in megakaryopoiesis and thrombopoiesis, and these genes have been observed to be co-amplified in acute myeloid leukaemia. Recent findings suggest a more significant role for the ACHE gene in haemopoiesis by regulating multipotent stem cell proliferation, and apoptosis in cells undergoing erythroid and myeloid differentiation. This led us to investigate gene copy-number alterations at these genes in MDS and AML. Samples were screened by slot-blot hybridization, and if changes were observed, by Southern blotting. A total of 42 samples from 31 de novo AML patients, 10 samples from eight cases of post-MDS AML and 85 samples from 67 MDS patients were analysed with probes for ACHE, BCHE, c-MYC, MDR-1 and globin control. Changes in ACHE and/or BCHE were observed in 9/31 de novo AML patients, and in 7/67 MDS patients: 1/37 cases of refractory anaemia (RA), 1/10 cases of refractory anaemia with excess blasts (RAEB) and 5/20 chronic myelomonocytic leukaemia (CMML) patients. The amplification events observed generated copy numbers no greater than 10, showed normal restriction patterns and had no clear correlation with megakaryopoiesis or thrombopoiesis. Loss of signal at the ACHE locus was observed: haploid signal intensity was seen in seven samples: one RA with thrombocytopenia, three CMML, one AML-M5a (no karyotypic abnormalities of chromosome 7), one AML-M4 (monosomy 7), and one case of AML-M7 (karyotype unknown). Homozygous deletion was observed at relapse of an additional patient with AML-M4. These data reinforce the possibility that ACHE may play a role as a myeloid tumour suppressor gene.

Myelosuppressive chemotherapy to mobilize normal stem cells in chronic myeloid leukemia.

Ten patients with Ph+ chronic myeloid leukemia (CML) were treated with idarubicin, cytarabine and etoposide followed by G-CSF to harvest Ph-negative progenitor cells. Six were in first chronic phase (CP1), and four beyond CP1. Between two and six aphereses (median 3, total 36) were performed starting 9-26 days (median 14.5) after chemotherapy when the leukocyte count was 0.6-4.7 x 10(9)/l (median 1.2). 1.3-3.6 x 10(8) mononuclear cells/kg (median 2.8), 0-128.4 x 10(4) CFU-GM/kg (median 1.2; seven patients) and 0.3-25.1 x 10(6) CD34+ cells/kg (median 9.8; seven patients) were collected. Seven of 27 harvests showing metaphases were 100% Ph-negative, 11 partially Ph-negative, and nine were 100% Ph+. All three patients with 100% Ph-negative collections were in CP1 and within 4-26 months of diagnosis. Four of six CP1 patients showed significant cytogenetic response compared with none of four beyond CP1 (P = 0.036). The absolute neutrophil count remained < 0.5 x 10(9)/l for 9-44 days (median 15.5) following chemotherapy. Four patients (three Ph-negative) were autografted after 16 mg/kg busulfan (n = 2) or 200 mg/m2 melphalan (n = 2). One of the three patients receiving Ph-negative cells died of graft failure, and two are alive with 15% and 50% Ph-negative cells at 15 and 11 months on interferon-alpha. We conclude that it is possible to harvest Ph-negative cells after myelosuppressive chemotherapy in some CML patients treated early in the course of CP1. However, in view of lack of consistent response, investigation of alternative approaches is necessary.

Unusual myeloid leukaemia in patient with Hodgkin's disease.

An unusual case of leukaemia in a patient with Hodgkin's disease is described. The leukaemic blast cell population was typified by the presence of a substantial proportion of binucleate and multinucleate cells, many of which had the morphological features of Sternberg-Reed cells. The circulating and bone marrow blast cells were shown by immunophenotyping to be of myeloid origin.

Mosaic trisomy 2 in myelodysplastic syndromes and acute myeloblastic leukemias.

We present a short report here of two more patients with trisomy 2 as the sole chromosomal abnormality in a hematologic malignancy. Although trisomy 2 is a recognized abnormality in neoplasms, particularly hepatoblastomas, to the best of our knowledge only three other cases have been reported with trisomy 2, in patients with a hematologic malignancy. The two cases presented here of myelodysplastic syndrome transforming to acute myeloblastic leukemia and chronic myelomonocytic leukemia showed trisomy 2 as the sole abnormality.

Consistent interstitial chromosomal deletions in myeloid malignancies and their correlation with fragile sites.

Chromosomal deletions occurring in myeloid malignancies have sometimes been reported either with no breakpoints or as terminal deletions. It is of importance to deduce whether these deletions are actually terminal or interstitial because this has implications for their biologic consequences and the mechanism of their development. Chromosomal deletions have been observed in 38 patients with myeloid malignancies. Two or more deletions occurred in six cases, and in seven cases this was part of a complex abnormality. In all, 45 deletions were observed. In all cases analyzed, the deletions consistently were interstitial. Of the 38 cases, 16 were myelodysplastic syndromes (MDS) [refractory anemia (RA), three; RA with ringed sideroblasts (RARS) three; RA with excess of blasts (RAEB) eight; RAEB in transformation (RAEB-t) one; and unclassified, one], 11 cases were acute nonlymphocytic leukemia (ANLL), and 11 were other myeloproliferative disorders [polycythemia rubra vera (PRV) seven; essential thrombocytopenia (ET), three; unclassified, one]. In general, no uniformity of breakpoints could be identified other than del(9)(q13q22.2) most of which occurred with t(8;21) and del(20)(q11.2q13.3 or 13.1). The breakpoints corresponded to or were adjacent to fragile sites in 49% (proximal 64%, distal 33%). These data emphasize that chromosomal deletions in myeloid malignancies are interstitial. The uniformity of breakpoints in del 9q and del 20q supports the concept that in some instances the exact breakpoints may be important through juxtaposition of genes rather than loss of critical regions. The data also suggest that there may be different mechanisms for the development of proximal and distal breakpoints.

Duplication of one of the products of the t(8;21) translocation in a patient with refractory anemia with excess blasts in transformation.

A 34-year-old man with refractory anemia with excess blasts in transformation is reported, having a t(8;21) translocation and a duplication of one of the products, der(21). The duplicated product had not been observed at presentation in malignant disease, as far as we are aware; thus, the findings are discussed with regard to this case and other possible smoldering leukemias. The diagnostic use of cytogenetics is also considered.

Deletion of chromosome arm 15q and hitherto unreported duplication of del(15q) in myeloid disorders.

Deletion of the long arm of chromosome 15 has been described as a recurrent chromosomal abnormality in myeloid malignancies. We present here some additional case reports of deletion 15 including two cases with an extra copy of the deleted chromosome, a finding that has not previously been described. We compare our cases to those previously reported. Our findings show that, contrary to previous reports, this abnormality may not always be associated with an unfavorable prognosis. They also indicate that deletion 15q most frequently appears to be associated with myelomonocytic disease. Potential candidate genes on 15q that may be involved in the tumorigenesis of these cases are discussed.

Epstein-Barr virus-related post-transplant lymphoproliferative disorder with t(9;14)(p11-12;q32).

The immunoglobulin heavy chain gene locus on 14q32 is known to be involved in translocations that are associated with B-lymphoproliferative disorders, typically Burkitt lymphoma and B-cell acute lymphoblastic leukemia. Several cytogenetic abnormalities have been described in post-transplant lymphoproliferatve disease (PTLD), some of which include this locus. To our knowledge, we report the first case of translocation t(9;14)(p11-12;q32) in a PTLD that developed after orthoptic liver transplantation.

Subtle abnormalities in the short arm of chromosome 11 in acute myeloid leukemia.

A series of four patients with small deletions of the short arm of chromosome #11 is presented. In two of these patients, deletion of 11p was the sole karyotypic abnormality. When compared with similar reported cases an association with FAB type M4 is apparent. Such cases may often be undocumented, because the deletions can be subtle. One patient with erythroleukemia shows an inversion of chromosome #11 involving band 11p15. Because the patients' fetal hemoglobin (HbF) became raised during the course of the disease, it is postulated that the hemoglobin beta chain gene at 11p15 may have been disrupted.

Reducing MCM levels in human primary T cells during the G(0)-->G(1) transition causes genomic instability during the first cell cycle.

DNA replication is tightly regulated, but paradoxically there is reported to be an excess of MCM DNA replication proteins over the number of replication origins. Here, we show that MCM levels in primary human T cells are induced during the G(0)-->G(1) transition and are not in excess in proliferating cells. The level of induction is critical as we show that a 50% reduction leads to increased centromere separation, premature chromatid separation (PCS) and gross chromosomal abnormalities typical of genomic instability syndromes. We investigated the mechanisms involved and show that a reduction in MCM levels causes dose-dependent DNA damage involving activation of ATR & ATM and Chk1 & Chk2. There is increased DNA mis-repair by non-homologous end joining (NHEJ) and both NHEJ and homologous recombination are necessary for Mcm7-depleted cells to progress to metaphase. Therefore, a simple reduction in MCM loading onto DNA, which occurs in cancers as a result of aberrant cell cycle control, is sufficient to cause PCS and gross genomic instability within one cell cycle.

A human myeloma cell line suitable for the generation of human monoclonal antibodies.

Ever since monoclonal antibodies were produced in 1975 with mouse myeloma cells there has been interest in developing human myeloma cultures for the production of monoclonal antibodies. However, despite multiple attempts, no human myeloma line suitable for hybridoma production has been described. Here we report the derivation of a hypoxanthine-aminopterin-thymidine-sensitive and ouabain-resistant human myeloma cell line (Karpas 707H) that contains unique genetic markers. We show that this line is useful for the generation of stable human hybridomas. It can easily be fused with ouabain-sensitive Epstein-Barr virus-transformed cells as well as with fresh tonsil and blood lymphocytes, giving rise to stable hybrids that continuously secrete very large quantities of human immunoglobulins. The derived hybrids do not lose immunoglobulin secretion over many months of continuous growth. The availability of this cell line should enable the in vitro immortalization of human antibody-producing B cells that are formed in vivo. The monoclonal antibodies produced may have advantages in immunotherapy.

Transabdominal chorionic villus sampling.

Transabdominal chorionic villus sampling, carried out with a fine-bore needle and cannula under ultrasound guidance, was as successful as transcervical aspiration but avoided the risks of bacterial contamination associated with the latter technique. The transabdominal procedure can be carried out under local anaesthesia, and multiple samples can be obtained, if necessary, through a single cannula.

A practical assessment of ultrasound-guided transcervical aspiration of chorionic villi and subsequent chromosomal analysis.

Aspiration biopsy of trophoblastic villi was performed on 56 patients immediately preceding suction termination of pregnancy, using a malleable metal cannula and ultrasound guidance. Villi were obtained from 47 patients (84%), with sampling success rising to 93% after experience. Immediate complications were noted in 14% of patients and correlated with placental positions situated furthest from the cervical canal. Karyotyping from cultured and/or direct preparations was attempted on the villus samples and was successful in 42. Clarity of the karyotypes obtained from direct preparations in this series was not found to be adequate for diagnostic purposes. A number of practical suggestions which facilitate chorion villus sampling are described.