Juvenile chronic granulocytic leukemia in a patient with trisomy 8, neurofibromatosis, and prolonged Epstein-Barr virus infection

The epigenetic landscape of aneuploidy: constitutional mosaicism leading the way?

The role of structural genetic changes in human disease has received substantial attention in recent decades, but surprisingly little is known about numerical chromosomal abnormalities, even though they have been recognized since the days of Boveri as partaking in different cellular pathophysiological processes such as cancer and genomic disorders. The current knowledge of the genetic and epigenetic consequences of aneuploidy is reviewed herein, with a special focus on using mosaic genetic syndromes to study the DNA methylation footprints and expressional effects associated with whole-chromosomal gains. Recent progress in understanding the debated role of aneuploidy as a driver or passenger in malignant transformation, as well as how the cell responds to and regulates excess genetic material in experimental settings, is also discussed in detail.

Mosaiktrisomie 8p11.21q11.21 als Prädisposition für myeloische Leukämien

Bei der juvenilen myelomonozytären Leukämie (JMML) handelt es sich um eine myeloproliferative Erkrankung der frühen Kindheit. Bei vielen Patienten lassen sich zugrunde liegende somatische, aber auch konstitutionelle Mutationen in NRAS, KRAS, PTPN11, NF1 und CBL nachweisen. Zur Identifizierung submikroskopischer Veränderungen, die für die leukämische Transformation von Bedeutung sein können, wurden 20 JMML-Proben mittels hochauflösender Oligo-Microarray-basierter komparativer genomischer Hybridisierung (aCGH) untersucht. Bei 2 von 10 Patienten mit submikroskopischen Aberrationen konnte ein nahezu identischer Zugewinn von Chromosom 8 gezeigt werden, der sich in weiteren Untersuchungen als konstitutionelles Mosaik darstellte. Eine Übersicht von 27 Patienten mit einem konstitutionellen Trisomie-8-Mosaik (cT8M) und maligner Neoplasie zeigte, dass es sich meist um myeloische Neoplasien, auch JMML, handelt. Durch unsere Untersuchungen konnte die kritische Region auf Chromosom 8, deren Loci mutmaßlich an der Leukämieentstehung und/oder Progression beteiligt sein können, dramatisch reduziert werden: 8p11.21q11.21. Es bleibt zu klären in welcher Form das partielle Trisomie-8-Mosaik an der Leukämieentstehung beteiligt ist und in welcher Weise dies für verschiedenen Mutationssubtypen der JMML eine Rolle spielt.

Constitutional trisomy 8p11.21-q11.21 mosaicism: a germline alteration predisposing to myeloid leukaemia

Juvenile myelomonocytic leukaemia (JMML) is a unique myeloproliferative disorder of early childhood. Frequently, mutations in NRAS, KRAS, PTPN11, NF1 or CBL are found in these patients. Monosomy 7 is the most common cytogenetic aberration. To identify submicroscopic genomic copy number alterations, 20 JMML samples were analysed by comparative genomic hybridization. Ten out of 20 samples displayed additional submicroscopic alterations. In two patients, an almost identical gain of chromosome 8 was identified. In both patients, fluorescence in situ hybridization confirmed a constitutional partial trisomy 8 mosaic (cT8M). A survey on 27 cT8M patients with neoplasms showed that 21 had myeloid malignancies, and five of these had a JMML. Notably, the region gained in our cases is the smallest gain of chromosome 8 reported in cT8M cases with malignancies so far. Our results dramatically reduce the critical region to 8p11.21q11.21 harbouring 31 protein coding genes and two non-coding RNAs, e.g. MYST3, IKBKB, UBE2V2, GOLGA7, FNTA and MIR486--a finding with potential implications for the role of somatic trisomy 8 in myeloid malignancies. Further investigations are required to more comprehensively determine how constitutional partial trisomy 8 mosaicisms may contribute to leukaemogenesis in different mutational subtypes of JMML and other myeloid malignancies.

Constitutional aneuploidy and cancer predisposition

Constitutional aneuploidies are rare syndromes associated with multiple developmental abnormalities and the alterations in the risk for specific cancers. Acquired somatic chromosomal aneuploidies are the most common genetic aberrations in sporadic cancers. Thus studies of these rare constitutional aneuploidy syndromes are important not only for patient counseling and clinical management, but also for deciphering the mechanisms by which chromosomal aneuploidy affect cancer initiation and progression. Here we review the major constitutional aneuploidy syndromes and suggest some general mechanisms for the associated cancer predisposition.

A novel t(8;18)(q13;q21) in acute monocytic leukemia evolving from constitutional trisomy 8 mosaicism

Constitutional trisomy 8 mosaicism (CT8M) has been considered to be the first mutation in multistep carcinogenesis. We describe the case of a 38-year-old woman with a normal phenotype who developed to acute monocytic leukemia with a novel t(8;18)(q13;q21). Chromosome analysis and spectral karyotyping showed 47,XX,+8,t(8;18)(q13;q21)[20]. Fluorescence in situ hybridization (FISH) demonstrated that the breakpoint at 18q21 was centromeric to the MALT1 and BCL2 genes. FISH also revealed that trisomy 8 was detected in buccal mucosa cells, indicating that trisomy 8 was a constitutional abnormality. These results suggest that t(8;18)(q13;q21) had a crucial role in the development of leukemia as the second mutation following CT8M.

Constitutional trisomy 8 mosaicism with myelodysplastic syndrome complicated by intestinal Behcet disease and antithrombin III deficiency

Trisomy 8 is the most common acquired chromosomal abnormality associated with myeloid malignancy. As a constitutional trisomy 8 mosaicism (T8M), it exhibits an extremely variable phenotype. In addition, Behcet disease (BD) has been reported as an unusual complication of myelodysplastic syndrome (MDS). To our knowledge, 12 case reports of various hematologic malignancies in patients with T8M and 18 case reports of MDS with acquired trisomy 8 complicated by BD have been published to date. We report a case of constitutional T8M with MDS complicated by intestinal BD and antithrombin III deficiency.

Constitutional trisomy 8 mosaicism due to meiosis II non-disjunction in a phenotypically normal woman with hematologic abnormalities

Constitutional trisomy 8 mosaicism (CT8M) in liveborns is typically caused by mitotic non-disjunction and exhibits wide phenotypic variability. By contrast, CT8M due to meiotic errors usually results in miscarriage. We describe a case of CT8M due to a paternal meiosis II non-disjunction error. The patient, a 32-year-old woman, was phenotypically normal except for a history of recurrent aphthous ulcers since childhood and a 4-year history of macrocytosis. The ulcers were refractory to steroids, but responded well to thalidomide. To the best of our knowledge, this is the first report of CT8M due to meiotic non-disjunction in a phenotypically normal individual.

Constitutional chromosome aberrations as pathogenetic events in hematologic malignancies

A predisposition to tumor development is associated with some constitutional chromosomal abnormalities. Investigations of families with an apparent hereditary cancer and constitutional chromosome rearrangements have led to the molecular identification of tumor suppressor genes. Under the somatic mutation theory for the development of cancer, two mutational events are required. The first step may be a constitutional event and the second an acquired genetic mutation. Cytogenetic studies were performed on 5633 bone marrow specimens from patients with hematologic malignancies from a single institution. Fifty cases of constitutional chromosome aberrations were detected. Data collected from the literature and from our series are reviewed and compared with the incidence of specific constitutional chromosome aberrations in the newborn population. Possible mechanisms that may predispose individuals with constitutional chromosome aberrations to the development of a hematologic malignancy are reviewed.

Chronic myelomonocytic leukaemia in a child with constitutional partial trisomy 8 mosaicism

We present a 3-year-old boy with constitutional partial trisomy 8 mosaicism (karyotype 47,XY, + del(8)(p12)/46,XY) who developed chronic myelomonocytic leukaemia and we review the few reported cases of constitutional trisomy 8 mosaicism (CT8M) associated with malignancy. This case highlights the association between CT8M and the development of malignancies, haematological malignancies in particular.

c-myc locus amplification and the acquisition of trisomy 8 in the evolution of chronic myeloid leukaemia

The biological progression of chronic myeloid leukaemia is often associated with secondary cytogenetic abnormalities but the molecular mechanisms underlying this progression are poorly understood. This study explores the association of c-myc gene amplification with the progression of chronic myeloid leukaemia in fourteen individuals. Three of these cases showed amplification of c-myc during the course of their disease. Cytogenetic and molecular analysis of serial samples from some patients suggested the successive expansion of distinct clones of malignant cells. Our findings also suggest that trisomy 8 and locus amplification could represent alternative mechanisms for increasing c-myc gene dosage.

Constitutional trisomy 8 as first mutation in multistep carcinogenesis: clinical, cytogenetic, and molecular data on three cases

Three patients, with constitutional trisomy 8 mosaicism (CT8M), who developed a malignancy are reported. The diagnoses were refractory anaemia, acute lymphoblastic leukaemia, and idiopathic myelofibrosis. In the child with acute leukaemia, the CT8M was diagnosed at birth due to severe dysmorphisms and malformations; the other two patients showed a milder phenotype, and the CT8M was diagnosed only after the finding of trisomy 8 in neoplastic cells. The review of eight similar, previously reported cases and the clinical, cytogenetic, and molecular studies performed in our patients led us to make the following observations: (I) CT8M predisposes to neoplasms, preferentially to myelo- or lymphoproliferative diseases; (2) a gene dosage effect for glutathione reductase in red blood cells was seen in two of our patients; (3) the wide phenotypic variation of CT8M was confirmed: trisomy 8 in neoplastic cells of phenotypically near-normal cases may be misinterpreted as acquired; and (4) molecular studies suggested a postzygotic origin of the trisomy in our three cases, with the supernumerary chromosome being of paternal origin in one case and of maternal origin in the other two. We postulate that the trisomy 8 in neoplasms may often occur by mitotic nondisjunction in an early embryonic multipotent cell and that what is usually interpreted as an acquired trisomy 8 may in fact be CT8M. The constitutional trisomy 8 would act as a pathogenetically important first mutation in multistep carcinogenesis. Whenever trisomy 8 is found in malignancies, the patient should be reevaluated clinically to exclude CT8M, and CT8M patients should be monitored for the possible development of malignancies.

Aspects of the neoplasms observed in patients with constitutional autosomal trisomy

A review of the literature reveals numerous clinical case reports, systematic histologic analyses, epidemiologic studies, and large series of tumors showing that subjects with trisomy 8, 9, 13, 18, and 21 have an excess of hematologic and various solid tumors compared to the general population. These tumors more frequently affect particular organs for a given type of trisomy. A large proportion of tumors are observed during fetal and neonatal life, are incompletely developed, and subsequently regress. In older children or even adults, tumors are less frequent, are often found on the same organs as earlier in life, are more aggressive, and do not involute. The mechanism responsible for the development of these neoplasms could be similar to that which generates the malformations in these children and may result from cooperation of the chromosomal abnormality with physiologic growth phenomena, which are particularly active early in life. Trisomic subjects must be carefully followed in order to detect tumors as early as possible and to allow treatment under optimal conditions.

Constitutional and acquired trisomy 8

Trisomy 8 is seen in a range of disorders both constitutional and acquired. The full constitutional condition presents with physical stigmata, skeletal abnormalities and a mild to moderately retarded IQ. Trisomy 8 is frequently seen as a mosaic in the blood or in the skin or both. Trisomy 8 as an acquired condition is found in haematological disorders, notably in myelodysplasia (MDS) and acute myeloid leukaemia (AML), and is restricted to the malignant cells. These arise in the bone marrow and may also be found in the peripheral blood. Reported in the issue (Zollino et al. (1995) Leukemia Res. 19(10), 733) is a case of a patient with constitutional trisomy 8 mosaicism who developed myelodysplasia with trisomy 8 in 95-100% of bone marrow cells. Here we consider the implications of this case to the diagnosis of both malignant and constitutional conditions.

Juvenile chronic myelocytic leukemia--report of 10 cases

Ten children (five boys and five girls) with juvenile chronic myelocytic leukemia were seen over a period of 12 years (1980-1991) at the All India Institute of Medical Sciences, New Delhi. With the exception of one who was aged 4.5 years, all children were below 4 years of age (mean age 20.4 months). The presenting features included fever, bleeding secondary to thrombocytopenia, marked hepatosplenomegaly, and skin rash. The striking hematological features were anemia, thrombocytopenia, peripheral blood monocytosis, and normoblastemia. There was no significant myeloid proliferation in the bone marrow aspirate (mean M:E = 5:1), while erythroid proliferation was prominent along with monocytosis (mean 11.2%). Fetal hemoglobin was raised in 8 of the 10 patients (mean 14.1%). Long-term survival was poor, with maximum survival being 18 months in one case. New modalities of management of this rare entity are discussed.

Myelodysplastic syndrome in a child with constitutional trisomy 8 mosaicism and normal phenotype

Trisomy 8 is a frequently acquired cytogenetic abnormality in myeloid malignancies, but may also represent a constitutional chromosome abnormality with a wide phenotypic variation. We report a case of myelodysplastic syndrome (MDS) that developed in a child with trisomy 8 mosaicism and normal phenotype. Bone marrow (BM) cells all showed trisomy 8 with additional clonal abnormalities in most cells. Based on the present case and a review of previously published cases of myeloid malignancies in patients with trisomy 8 mosaicism, it appears likely that the malignant cells developed from the trisomic cell population, suggesting that constitutional trisomy 8 may be a predisposing condition to myeloid malignancies. Trisomy 8 in malignant cells is usually considered an acquired abnormality, but this implies a risk of ignoring a constitutional trisomy 8 mosaicism. Examination for constitutional trisomy 8, despite a normal phenotype, may therefore be warranted in hematologic malignancies with trisomy 8 of BM cells to evaluate further the possible association and to preclude erroneous use of trisomy 8 as a tumor marker.

Myelodysplastic syndromes in childhood--classification, epidemiology, and treatment

Much of the applied terminology of myelodysplastic syndromes (MDS) in childhood is confusing and not mutually exclusive. It is therefore proposed that the FAB classification of MDS is used in children in order to improve diagnostic precision and to facilitate epidemiologic, clinical, and therapeutic comparisons. The true incidence of childhood MDS is unknown but the rate may approximate the incidence of acute myelogenous leukemia. A pooled analysis of eight larger series representing 110 children less than 15 years old at diagnosis with de novo MDS classified according to the FAB recommendations showed that the more aggressive subtypes dominated, which partly may reflect that the less advanced cases are underdiagnosed. The median age at presentation was 6.0 years. The male/female ratio was 1.6. Monosomy 7 was the most frequent cytogenetic abnormality. The median survival was 13 months and the probability of survival three years from diagnosis was 16%. Spontaneous remission may be observed very infrequently. Allogeneic bone marrow transplantation (BMT) represents the only potentially curative treatment. The survival rate three years after BMT is about 50%. Major differences between childhood and adult MDS exist with respect to the distribution of FAB subgroups, the rate of progression, and the cytogenetic findings. The literature on MDS in children is still sparse and there is an obvious need for more studies designed to determine the incidence, clinical and laboratory characteristics, the natural course, and the efficacy of contemporary treatment options.

Von Recklinghausen neurofibromatosis and hematologic malignancies: 2 case reports in adulthood

Von Recklinghausen's neurofibromatosis is a hereditary disease predisposing to distinctive malignant hemopathies. These often develop during early childhood and are characterized by particular cytologic subtypes: juvenile chronic myeloid leukemia, monosomy 7-associated myeloproliferative syndrome and myelomonocytic leukemia. The etiopathologic mechanism underlying this association begins to be elucidated: the neurofibromatosis gene behaves like a tumor suppressor gene; its inactivation by mutation results in activation of the corresponding oncogenes. We report here the cases of two late-aged adults with neurofibromatosis: the first developed acute myelogenous leukemia, the second polycythemia vera. Based on a review of the literature, we suggest that, in opposition to childhood, the association between neurofibromatosis and malignant blood diseases is not demonstrated in adulthood.

Chronic leukaemias

In recent years many subtypes of CLL and some CML variants have been recognized throughout the world by means of careful clinical, epidemiological, immunological, molecular biological and viral studies. Most striking has been the establishment of a close association between certain immunophenotypical subtypes of CLL and infection with HTLV-I and possibly HTLV-II. CLL has consistently been shown to have a strong genetic component and a low incidence among Asians, but a growing body of evidence also links this major leukaemia type with environmental factors including solvents, unidentified farming and other occupational exposures. In contrast, CML is characterized by few genetic associations, relatively homogenous world-wide distribution, greater frequency in Blacks than in Whites, little evidence of viral aetiology, and evidence that exposures to ionizing radiation, benzene and possibly other chemical agents are important aetiological factors. Most studies suggest that acquired rather than genetic factors are of greater importance in the aetiology of CML, but this conclusion is somewhat difficult to reconcile with the relatively small variation in incidence rates internationally. Common to both disorders in most populations are an increasing incidence with age, male predominance, and stability of incidence, survival and mortality over the years, exclusive of improved survival of CML following allogeneic bone marrow transplantation.

Circinate plaques heralding juvenile chronic myelogenous leukemia

Plaques of leukemia cutis were the first manifestation of juvenile chronic myelogenous leukemia in a 2-year-old. This is a rare and usually fatal form of childhood leukemia. Only three cases of leukemia cutis associated with juvenile chronic myelogenous leukemia have been published.

Neurofibromatosis and acute monocytic leukemia in adults

A patient with nonfamilial peripheral neurofibromatosis (NF) (von Recklinghausen's disease) is reported who contracted acute monocytic leukemia at 60 years of age. In the course of the illness, myelonecrosis developed and the patient died 4 months later due to a therapy-resistant bone marrow relapse. This association of the two illnesses would appear to confirm reports on an increased incidence of nonlymphatic leukemia and NF. Such an association is seen during childhood as juvenile chronic leukemia, but it is uncommon in adulthood.

Chronic leukemias of childhood

Chronic leukemias account for fewer than 5 per cent of childhood hematologic malignancies. The various subtypes are chronic mylocytic leukemia (adult, juvenile, and familial), chronic myelomonocytic leukemia chronic monocytic leukemia, and chronic lymphocytic leukemia. The most common of these, adult-type chronic myelocytic leukemia, is characterized by specific cytogenetic alterations; recent advances in molecular biology are linking these genetic events to the pathophysiology and course of this fascinating neoplasm.

Malignant lymphoma arising in a large congenital neurofibroma of the head and neck. Report of a case

A lymphoma developed in a large neurofibroma in a young woman who had no other stigmata of neurofibromatosis. The neurofibroma was congenital and extensively involved the soft tissue and bone of the face and neck. Despite multiple attempts to excise the neurofibroma, it persistently recurred. At the age of 30 the patient underwent another resection of the lesion, and a follicular, mixed, small and large cell lymphoma was present within the neurofibroma. Over 3 years the lymphoma transformed into a diffuse large cell type despite the fact that it remained localized to the neurofibroma. After the lymphoma had transformed, the patient received multiagent chemotherapy. She responded well, and a repeat biopsy showed no residual lymphoma. She is alive and well 25 months after completion of chemotherapy. To the best of our knowledge, this is the first report of a lymphoma arising in a soft tissue neoplasm.

Linkage analysis of peripheral neurofibromatosis to DNA markers on chromosome 8

Linkage relationships of the gene for peripheral neurofibromatosis (NF) were assessed in a large American Caucasian pedigree using two DNA markers located on chromosome 8. Linkage to the thyroglobulin locus, located at 8q24, was excluded (lod less than or equal to -2.0) to 21 cM. Data obtained for the tissue plasminogen activator locus, located at 8p12, excluded linkage to 4 cM. These results exclude between 20 to 30% of chromosome 8 as a possible map location for the NF gene in this family. Comparison of the two DNA markers excluded their linkage to 0.5 cM.