The 5a-chromosome abnormality in haematological disorders: a collaborative study of 34 cases from the Netherlands

The 5q- syndrome

The 5q- syndrome is a distinct hematological disorder with typical laboratory, morphological, cytogenetic, molecular, and prognostic features. It is defined as a myelodysplastic syndrome with a medullary blast count <5% and an isolated interstitial deletion of the long arm of chromosome 5, including bands q31-q33. The molecular basis of this disease has not yet been fully elucidated, but there is evidence that a commonly deleted region of 1.5 Mb harbors one or several tumor suppressor genes, the loss of which being the basic event leading to disease activity. The 5q- deletion has been demonstrated in very early hematopoietic precursors, including CD34+CD133+ and CD34+CD38-Thyl+ cells. Analysing data of 60 patients with the 5q- syndrome that were followed over a period of up to 28 years, we found a median age at diagnosis of 66.8 years and a female preponderance with a male to female ratio of 1:1.5. Anemia is usually macrocytic and combined with low reticulocyte counts and high erythropoetin levels. Three types of cytogenetic deletion are most prevalent: del(5)(q13q33), del(5)(q13q31) and del(5)(q22q33). The 5q- syndrome has a good prognosis with a median overall survival of 107 months at a median follow-up of 53 months, and a low probability of transformation to AML. An increase of the medullary blast count to > or =5% or the addition of one karyotypic anomaly severely reduces median overall survival. The most promising therapeutic approach is the novel thalidomide analogue CC5013 that is currently evaluated in an international phase II study.

Primary myelodysplasia occurring in adults under 50 years old: a clinicopathologic study of 52 patients

Although myelodysplastic syndromes (MDSs) are generally thought to be diseases of elderly patients, younger patients also have rarely been diagnosed with MDS. This is a report of the clinical, morphologic and cytogenetic features of 52 cases of primary MDS occurring in adults under the age of 50 years. Cases secondary to chemotherapy or radiotherapy were excluded. There were 31 males and 21 females. The median age at presentation was 39 years (range, 18 to 49 years). The interval between onset of symptoms and diagnosis was brief (median, 4 weeks; range, 1-32 weeks). Of the 49 patients for whom information about duration of symptoms was available, 13 (27%) were asymptomatic. Forty-two (81%) of the patients were classified using FAB criteria for blood and bone marrow morphology: refractory anemia (RA), 11; refractory anemia with ringed sideroblasts (RARS), four; refractory anemia with excess blasts (RAEB), 12; chronic myelomonocytic leukemia (CMML), three; refractory anemia with excess blasts in transformation (RAEB-T), 12 patients. Ten patients could not be categorized. Abnormalities involving chromosome 7 was the most frequent cytogenetic abnormality (31%). Partial chromosomal deletion and chromosome gain were also common abnormalities (22% and 9%, respectively). Translocations accounted for only 9% of the main cytogenetic abnormalities encountered in this patient population. For the 49 patients for whom information regarding AML transformation was available, 23 (47%) progressed to acute myeloid leukemia, with an overall median time to progression of 2 months (range 3 weeks to 3 years). In each category except for RARS, approximately half of the patients progressed, with a slightly less median time to progression in RAEB-T than for the other subtypes of MDS. Thirteen patients underwent bone marrow transplantation at the time of presentation of their disease.

5q- syndrome presenting chronic myeloproliferative disorders-like manifestation: a case report

A 28-year-old Japanese woman with suspected essential thrombocythemia (ET) had marked thrombocytosis, mild leukocytosis with normal neutrophil alkaline phosphatase activity, and no anemia. She was monitored without being given any medication. Eleven years later, complete blood counts showed no remarkable changes but some non-lobulated mononuclear megakaryocytes were found in the bone marrow. Cytogenetic analysis revealed deletion of the long arm of chromosome 5 (5q-). Subsequently, hemoglobin and platelet counts decreased gradually, splenomegaly appeared and progressed, after which myelofibrosis developed. Acute leukemia developed 16 years after the first documentation of thrombocytosis. 5q- syndrome is known to be a myelodysplastic syndrome (MDS) with unique clinical features and cases with this syndrome presenting with thrombocytosis of more than 1,000 x 10(9)/L but without anemia are rare. Furthermore, it is noteworthy that in this patient transition to acute leukemia occurred following development of myelofibrosis and marked splenomegaly, which are generally observed in blastic crises resulting from chronic myeloproliferative disorders (CMPD). The patient showed features indicative of CMPD rather than of MDS in spite of presenting with 5q- chromosomal abnormality. This case supports the concept of "mixed myelodysplastic and myeloproliferative syndromes" and suggests the possibility of the appearance of CMPD-like manifestations in 5q- syndrome.

Translocation (X;5)(q13;q33) in essential thrombocythemia

We report a novel chromosomal translocation (X;5)(q13;q33) in a woman with no history of prior chemotherapy or radiotherapy, found to have essential thrombocythemia. Aberrations in chromosome 5, mostly deletions of 5q, have been described in essential thrombocythemia; however, a t(X;5) translocation has not been reported.

A case of childhood acute myeloid leukemia associated with inversion (7)(p21q31)

We describe a case of acute myeloid leukemia in a 2 1/2-year-old boy presenting with a mediastinal tumor causing respiratory distress, and lymph node enlargement in the cervical and inguinal regions. Apart from myeloid markers CD13 and CD33, blast cells also expressed stem cell marker CD34 and megakaryocytic marker CD61. Cytogenetically, inv(7)(p21q31) was found in 9/25 and 15/25 analyzed metaphases from short-term cultures of lymph node and bone marrow cells, respectively. The patient is in continued complete remission 26 months post diagnosis. The case demonstrates that chromosome aberrations other than inv(16), t(8;21), and t(9;11) may be associated with extramedullary disease, and that not all chromosome 7 aberrations are prognostic adverse findings.

5q(-)survival: importance of gender and deleted 5q bands and survival analysis based on 324 published cases

Survival of 5q(-)patients is known to depend on patient age, diagnosis, and acquisition of additional chromosome aberrations. The possible importance of the deleted 5q bands is unknown; nor is it known if the same or different factors are of prognostic importance in 5q(-)MDS and 5q(-)AML. In order to obtain material of sufficient size to answer these and other questions the literature was searched for 5q(-)cases with data on survival. Only MDS and AML cases with interstitial deletions were included. The results confirmed the prognostic importance of the factors mentioned above, but produced the following new data: In MDS, but not in AML, loss of the band 5q12 is an independent adverse prognostic factor; female patients survive longer in MDS while in AML men are the longer survivors; del(5)(q13q31) was found to be associated with MDS, 5q(-)as the sole aberration, and a long survival; on the other hand many del(5)(q12q32) cases showed AML, presence of additional aberrations, and short survivals. On the basis of these results the following hypotheses are proposed: 1) the female preponderance in 5q(-)MDS is due to longer female survival, and not to increased female incidence, and 2) some 5q deletions have a high diagnostic specificity, affect the rate of development of additional chromosome aberrations and thus in fact are major prognostic factors.

Chromosomal deletions in myelodysplasia

There are two major classes of genes implicated in human tumorigenesis, the oncogenes and the tumour suppressor genes. In haematological malignancies most emphasis has been placed upon the recurring translocations in which the juxtaposition of two gene sequences has resulted in the activation of an oncogene. Chromosomal loss rather than translocation is the most frequent karyotypic abnormality in the myelodysplastic syndromes, a heterogeneous group of clonal malignant blood disorders characterised by dyshaematopoiesis and/or impaired maturation of haemopoietic cells with frequent evolution to acute leukaemia. Recent attention has focused on the loss of genetic material as a result of chromosomal monosomy or deletion in the myelodysplastic syndromes. The most frequently reported deletions in these myeloid syndromes are of chromosomes 5, 20 and 7. Deletions of chromosomes 11, 12, and 13, although more rarely observed, are also characteristics of the myelodysplastic syndromes. It is probable that the deleted chromosomal bands give the location for as yet unidentified myeloid specific tumour suppressor loci and there is considerable interest in the cloning of these genes. This review discusses the three most frequently observed deletions in MDS; 7q deletion, 5q deletion and 20q deletion taking into account recent evidence on the respective critical regions of gene loss and the role of candidate genes.

Low-dose ARA-C consistently induces hematologic responses in the clinical 5q- syndrome

Five patients with the classical clinical syndrome associated with a deletion of the long arm of chromosome 5, i.e., anemia, macrocytosis, and thrombocytosis, or a normal platelet count, were treated successfully with subcutaneous low-dose cytosine arabinoside (LDARA-C). Prior therapy with other drugs had failed in four of the five patients. A total of nine complete and one partial hematologic responses were induced in five patients. Duration of the first hematologic response ranged from 3 to 30+ months. Two patients (cases 3 and 4) continue in their first hematologic response at 29 and 30 months. Upon relapse, up to three responses could be reinduced in two patients. Duration of the subsequent hematologic responses in case 1 was 16, 8, and 10 months and case 2 achieved two responses of 15 and 18+ months duration. LDARA-C therapy was associated with mild to severe neutropenia and moderate to severe thrombocytopenia. Thus, subcutaneous LDARA-C is highly effective in the treatment of patients with myelodysplasia associated with deletion of the long-arm of chromosome 5 (5q-).

Autoimmune-thrombocytopenia and SLE in a patient with 5q-anomaly and deletion of the c-fms oncogene

Autoimmune-thrombocytopenia was the striking feature in a patient with typical clinical symptoms of systemic lupus erythematosus (SLE), complement C4 deficiency, and positive lupus serology. However, myelodysplasia was found in the bone marrow and chromosome analysis revealed a deletion of the long arm of chromosome 5 (5q-anomaly), which was confirmed by a hemizygosity for the c-fms oncogene (CSF-1-receptor) on Southern blot. Autoimmune phenomena reported in conjunction with myelodysplastic syndromes (MDS), e.g., an elevation of antinuclear antibodies, are usually regarded as nonspecific. This case report suggests that SLE can occur in patients with MDS and that a concomitant autoimmune-thrombocytopenia may mask the typical signs of the 5q- syndrome.

t(5;12)(q31;p12). A clinical entity with features of both myeloid leukemia and chronic myelomonocytic leukemia

We report two patients with a myeloproliferative disorder (Philadelphia chromosome-negative chronic myeloid leukemia) and t(5;12)(q31;p12). Until now, only three cases of a translocation (5;12)(q31;p12) have been reported. All investigators had problems classifying their patient's disease into one of the well-defined entities of either MPD or myelodysplastic disorders. We postulate that this translocation may represent a subgroup of patients with features of both chronic myeloid leukemia and chronic myelomonocytic leukemia (CMMoL).

The prognostic value of cytogenetic analyses in patients with acute nonlymphocytic leukemia treated with the same intensive chemotherapy

BACKGROUND

Some specific chromosome abnormalities for the leukemias have been proven to be associated with the prognosis of acute nonlymphocytic leukemia (ANLL). However, most of these reports included patients treated with different protocols. Therefore, some bias has been involved in the evaluation of the prognostic factors in such reports.

METHODS

The authors studied the morphologic, cytogenetic, and clinical features of 136 patients (86 males and 50 females) with de novo ANLL treated with the same protocol of intensive induction chemotherapy using multivariate analyses.

RESULTS

Chromosome abnormalities were detected in 62.5% of the patients. The overall complete remission (CR) rate of disease was 85.5% in these patients. More than 90% of the patients with t(8;21) and pseudodiploid abnormalities achieved experienced CR. However, CR rates in the patients with abnormalities of chromosome 5 or 7 were 50%. With multivariate analyses by the type of karyotypic abnormality, CR duration and survival time of the patients with t(8;21) were longer than those of patients with normal karyotype and abnormalities of chromosome 5 or 7. Abnormalities of chromosome 5 or 7 and hyperdiploid were associated with poor prognosis. Older age and lower platelet counts also were factors contributing to shorter survival times. With the analysis with French-American-British (FAB) classification, only hypoplastic leukemia was a poor prognostic factor.

CONCLUSIONS

These data suggest that cytogenetic analyses plays an important role in estimating the prognosis of patients treated with intensive induction chemotherapy.

Cytogenetic studies in 112 cases of untreated myelodysplastic syndromes

Cytogenetic studies were performed in 112 untreated cases of myelodysplastic syndrome (MDS) between 1985 and 1990. Among 112 patients who were examined at the time of diagnosis, 54 had an abnormal karyotype (48%). The highest frequency of chromosome abnormalities was observed in refractory anemia with excess of blasts (RAEB) and RAEB in transformation (RAEB-t) and the lowest in refractory anemia with ring sideroblasts (RARS) and chronic myelomonocytic leukemia (CMMoL). Numerical changes were observed in 19 cases and structural in 17; chromosome 8 was most frequently gained (11 cases), whereas chromosome 7 was most frequently lost (6 cases), 5q- in 14 (4 as a sole anomaly); involvement of 7q22 was seen in 3 cases, 11p in 2 patients, 11q in 3 (one patient as a sole anomaly), 12p in 4 (2 patients as a sole anomaly), i(17q) in 4 (3 patients as a sole anomaly), and complex chromosomal defects in 10 patients. If one takes into account the prognosis value, a complex karyotype and the presence of ring chromosomes were correlated with the worst prognosis, followed by -7/7q-; an intermediate prognosis corresponds to i(17q), 12p as a sole anomaly, +8 (as a sole anomaly or plus other anomalies), and involvement of 12p. Patients with a 5q- as a sole anomaly or with a normal karyotype, had the best prognosis.

del(5q) in acute lymphoblastic leukemia with biphenotypic and early progenitor phenotype

We report three patients with acute lymphoblastic leukemia with biphenotypic and early progenitor phenotype who had del(5q). In the first patient, the del(5q) was the sole abnormality; in the second patient, the del(5q) was interpreted as subclonal evolutionary event; while in the third patient, the rearrangement was transiently present 7 months following the diagnosis of Ph-positive ALL, while the patient was in clinical remission. Review of the literature indicates that del(5q) is rare in ALL. In contrast to its presence in AML, del(5q) in ALL is not an adverse prognostic indicator, and it appears to be more frequent in children.

Loss of chromosome 22 in patients with refractory anemia with excess of blasts (RAEB) in transformation and acute leukemia after RAEB

We report studies of 12 patients with refractory anemia and excess of blasts in transformation (RAEB-t) and 17 with acute myeloblastic leukemia (AML) after RAEB. Besides chromosome 5 and 7 abnormalities, five patients with complex karyotypic changes had monosomy 22. This association is discussed in relation to the hypothesis of a suppressor gene located on chromosome 22.

Deletion of the long arm of chromosome 5 in essential thrombocythemia

A 51-year-old woman with no history of prior chemotherapy or radiation therapy was diagnosed with essential thrombocythemia (ET) according to the diagnostic criteria established by the Polycythemia Vera Study Group (PVSG). Cytogenetic analysis of bone marrow metaphases revealed both normal female karyotype and a single clonal abnormality, 46,XX,del(5)(q22q35). While chromosomal abnormalities have been reported in ET, their incidence is very low, and no specific abnormality has been found. Many of the reported cases of ET with chromosomal aberrations, including 5q-, do not meet the diagnostic criteria proposed by the PVSG, and may represent one of the other myeloproliferative disorders or a myelodysplastic syndrome. Furthermore, it is important to distinguish the 5q- syndrome, which may present with thrombocytosis and megakaryocytic hyperplasia, from ET. Our patient appears to be the first example of untreated ET clearly meeting the PVSG criteria in which 5q- was the only clonal abnormality seen at diagnosis.

Novel translocation (2;4) with consistent involvement of 2p23 in acute nonlymphocytic leukemia (M2)

A translocation involving the short arm of chromosome 2 and the long arm of chromosome 4 is described in three patients, all of whom had acute nonlymphocytic leukemia (M2). One patient had M2 de novo, one progressed from refractory anemia with excess blasts in transformation to M2 over a 4-month period, and one had had sideroblastic anemia 30 years prior to development of M2. In all three patients, the translocation involved the breakpoint p23 on chromosome 2, but the breakpoints on chromosome 4 varied between q25, q31, and q35. Translocations specifically involving 2p23 have not previously been described in leukemia, but more cases are required to identify a specific association with either the FAB type or prognosis.

Prognostic factors in the myelodysplastic syndromes

The myelodysplastic syndromes are acquired clonal hematologic malignancies characterized by progressive cytopenia and an increased risk of evolution to acute myeloid leukemia. It mainly affects elderly people, but may also be found in younger patients and children. MDS represents a heterogeneous group of disorders. Some patients will experience prolonged survival, whereas a substantial number of patients will die within the first year after diagnosis. Treatment of patients should be based on life expectancy. Patients with pancytopenia, excess of bone marrow blasts, complex chromosome abnormalities, abnormal chromosome 7, older age and secondary MDS have a poor prognosis. Several simple scoring systems are available, based on peripheral counts, percent of bone marrow blasts and age, that provide significant prognostic information about life expectancy in patients with MDS. The most widely used is the Bournemouth scoring system. The prognostic factors and the scoring systems are reviewed.

Red cell aplasia in myelodysplastic syndrome

Six cases of red cell aplasia occurring in patients with myelodysplastic syndromes (MDS) showed a diversity of clinical course and prognosis. In some patients red cell aplasia may have represented an evolution of MDS while in others autoimmune destruction of erythoblasts may have been the mechanism. A proliferative phase is seen in many of these patients, the clinical importance of which is uncertain.

Trisomy 5 in Ph+ chronic myeloid leukemia in association with megakaryocytosis

A patient with a megakaryocytosis associated with a Philadelphia chromosome-positive chronic myeloid leukemia (CML) was found to have a trisomy of chromosome five. To our knowledge, this is the first case of trisomy 5 associated with a Ph + CML, particularly one with a megakaryocytosis. The trisomy 5 may be associated with the resistance to cytostatic drugs found in this patient.

Refractory anemia with excess of blasts in transformation. Clinical, hematologic, and cytogenetic findings in nine patients

Clinical, hematologic, and cytogenetic data of nine patients with refractory anemia with excess of blasts in transformation (RAEB-t), classified according to the French-American-British Cooperative Group for myelodysplastic syndrome (MDS), are reported. At diagnosis, eight out of nine cases, had chromosomal abnormalities and three out of nine developed acute leukemia. Karyotype studies allowed individualization of two groups of patients: five with nonrandom major karyotype abnormalities (MAKA) including hypodiploidy, chromosomes 5 and 7 involvement, at least four other abnormalities, and a poor prognosis (survival always under 3.5 months); and four patients with either normal karyotypes or minor karyotype abnormalities (MIKA) (no more than three abnormalities) and a better prognosis (survival from 14 to 38 months). Karyotype appears to be a major prognostic factor among RAEB-t.

Translocation (1;5)(q23;q33) in adult acute non-lymphocytic leukemia

Chromosome banding studies carried out on bone marrow cells from a 57-year-old white caucasian male with an M1 acute non-lymphocytic leukemia (ANLL) revealed an unbalanced translocation involving chromosomes 1 and 5 [der(5)t(1;5)(q23;q33)] as part of complex abnormalities in 76% of the cells analyzed. This chromosomal abnormality is the first to be reported in an adult patient with acute non-lymphocytic leukemia. A review of previous reports on translocations involving the juxtaposition of the 1q23----qter DNA segment to other chromosomes suggests that this new translocation may be specifically involved with abnormal myeloid proliferation.

Red cell hypoplasia, thrombocytosis, and leucocytosis: myelodysplastic and proliferative syndrome

Three patients with chronic red cell aplasia also showed thrombocytosis or granulocytosis, or both. All had morphological evidence of myelodysplasia on examination of bone marrow aspirate but none had a detectable chromosomal abnormality. These patients seem to provide evidence of a separate entity within the spectrum of myelodysplastic and myeloproliferative disease.

Application of megakaryocytic morphology in diagnosing 5q- syndrome

In order to evaluate the diagnostic importance of the megakaryocytic morphology in the 5q- syndrome we studied the bone marrow from 48 unselected patients with myelodysplastic syndromes (MDS). 44 cases were primary and 4 secondary to cytostatic drug treatment or irradiation. There were 24 cases with chromosome anomalies, of whom 10 had del (5q). 4 of these had refractory anaemia (RA) with 5q- as the sole anomaly (group A), 2 had RA with 5q- and additional chromosome anomalies consisting of trisomy 8 (group B); 3 patients had RA with excess of blasts (RAEB) and complex, karyotypic changes also including 5q- (group B). Changes of the same type were found in 1 case of multiple myeloma with secondary MDS. All 6 RA patients with 5q- had characteristic megakaryocytes. More than 50% of the cells had no more than 2 nuclear segments, and predominantly had a diameter of 30 micron or more. No other patient with RA showed this picture. Only 1 patient with RAEB 5q- in group B had the same megakaryocytic changes. We conclude that diagnosis of a 5q- syndrome may be strongly suspected in cases of RA with these bone marrow changes. In cases of RAEB 5q- group B the bone marrow examination did not reveal the same consistent changes.

Effectiveness of attenuated chemotherapy in myelodysplastic syndromes: a preliminary report

A small group of elderly male patients received attenuated doses of daunomycin, cytosine arabinoside (Ara-C), and 6-thioguanine for treatment of myelodysplastic syndrome (MDS). Three patients had refractory anemia with excess blasts (RAEB), and two had chronic myelomonocytic leukemia (CMMoL). All five patients had developed severe transfusion requirements for platelets and red blood cells before therapy was begun. One patient developed necrosis of the cecum and expired 19 days after therapy, but the other four all showed substantial benefit from treatment. Three of those patients received multiple courses of chemotherapy which led to improvement in peripheral blood counts in each case. Duration of responses as noted by improvement in peripheral blood counts compared to pretreatment levels ranged from 1.5 to 9 months. Despite considerable improvement in peripheral blood parameters, some of the abnormal morphologic features of MDS persisted after each course of chemotherapy. These results obtained with attenuated chemotherapy schedules in a small group of patients are sufficiently encouraging to warrant an expanded phase II trial, which is under way at the University of Rochester Cancer Center.

Hematologic and clinical features of patients with chromosome 5 monosomy or deletion (5q)

This paper analyzes the hematologic features and outcome of 13 patients with chromosome 5 abnormalities (monosomy 5 or deletion of 5q), either isolated or with additional anomalies. Among four patients with isolated del (5q), two had a stable refractory macrocytic anemia with thrombocytosis (5q-syndrome). All nine patients with complex karyotypes had acute leukemia or refractory anemia with excess of blasts in acute transformation; two cases were TdT-positive, with a lymphoid or a mixed phenotype. In seven patients, preleukemia preceded overt leukemia, and in six, a prior therapeutic, or occupational exposure to mutagens/carcinogens had occurred. Additional chromosome 7 abnormalities were seen in four cases. The median survival of patients with complex karyotypes was 19 months from the time of diagnosis of the hematologic disorder and 5 months from the time of identification of the chromosome 5 abnormality. Pathogenetic implications of the chromosome 5 monosomy or del (5q) through a proto-oncogene activation and the putative hemopoietic stem cell involvement in a clonal disease are discussed.

Chromosome abnormalities in erythroleukemia

Erythroleukemia (EL) is a heterogeneous disease in terms of cell type affected, chromosome abnormalities found in the malignant clone, and clinical course. In this article, cases of erythroid EL from the recent medical literature are reviewed using cytogenetic criteria to distinguish such cases from those of myeloid EL. Although most patients with erythroid EL were elderly men, 20% of the cases occurred in the under-3 age group, where boys and girls were equally affected. Chromosomes 5 and 7 were found to be lost or partially deleted in two thirds of the adult patients only, but not in the pediatric patients; this suggests that EL is associated with cumulative mutagen exposure in adult patients only. It is proposed that cytogenetic criteria may be of use prospectively in distinguishing patients with erythroid EL from those with myeloid EL.

Translocations and deletions with breakpoint on 21q are nonrandomly associated with treatment-related acute nonlymphocytic leukemia and preleukemia

Six of 70 (8.6%) consecutive cases with therapy-related acute nonlymphocytic leukemia (ANLL) or preleukemia had a translocation or deletion with a breakpoint on 21q. Such aberrations were seen in only one of 200 (0.5%) consecutive cases of de novo ANLL examined at our laboratory. The figures reflect a 17.1-fold increased incidence of 21q aberrations in therapy-related ANLL or preleukemia, compared with ANLL de novo. The difference is highly significant (p = 0.003). The increased incidence of 21q aberrations in therapy-related myelodysplastic syndromes was confirmed by literature studies. Band 21q22 was most often involved. Cases with t(8;21), which is strongly associated with the M2 variant of ANLL, or cases with i(21q), which is supposedly due to a centromeric misdivision, were not included in the count. It is concluded that the 21q aberrations are associated with treatment-related ANLL or preleukemia with at least the same degree of specificity as aberrations of #5 and #7.

Specificity of haematological indicators for '5q- syndrome' in patients with myelodysplastic syndromes

83 patients with myelodysplastic syndromes were analyzed for the presence of three haematological features: (1) macrocytic anaemia, (2) normal or high platelet count and (3) megakaryocytic hypolobulation in most megakaryocytes. In 10 of the 83 patients, a 5q- chromosome was the only clonal aberration; 31 patients had other chromosomal aberrations (including 6 patients with 5q- chromosome and other abnormalities in the same clone) and 42 patients had a normal karyotype in their bone marrow cells. 9 patients displayed all three haematological features investigated. In 8 of these patients the 5q- chromosome was the only clonal aberration. The 9th patient had a karyotype of 47,XX, + 8. None of the 6 patients with 5q- chromosome and additional abnormalities in the same clone fulfilled all criteria. The '5q- syndrome', a situation with the 5q- chromosome as a sole aberration, should be accepted as a diagnostic entity within the macrocytic anaemias. This syndrome can be suspected on the basis of the above haematological indicators and the diagnosis confirmed with bone marrow karyotype analysis.

Trisomy 9 in hematologic disorders: possible association with primary thrombocytosis

Ten patients with a hematologic disorder and a clone of cells with trisomy 9 in the bone marrow were studied in order to investigate the clinical significance of this chromosome anomaly. In five of the patients, trisomy 9 was the only anomaly; in four, there was also trisomy 8; and in one, a Y chromosome was also lacking. Four patients had a myelodysplastic syndrome, and six had a myeloproliferative disorder. Interestingly, four patients had primary thrombocytosis.

Leukemic transformation in patients with the 5q- alteration: analysis of the behavior of the 5q- clones in preleukemic to leukemic phases

Serial cytogenetic studies have been performed in four patients with myelodysplastic syndromes. In all four a 5q- alteration was present, but with a different pattern of presentation. One patient presented 5q- as the only alteration since diagnosis; two patients acquired this alteration during the course of the disease; and the fourth showed a 5q- plus other alterations since the first cytogenetic study. Likewise, three of the four patients showed a clone with trisomy 8 and without 5q-. According to these observations and others from the literature with similar cytogenetic behavior, we have analyzed the following points: 5q- as a primary event and as the only alteration, 5q- as a secondary event, 5q- plus other alterations, and presence of cytogenetically different clones. Analysis of these points suggests that the 5q- alteration can represent an early mutation conferring a slow capacity of expansion to the affected clones, with the possibility of cytogenetic evolution during the progression of the disease (about 30% of the patients). Likewise, the association of trisomy 8 clones with 5q- clones can be a nonrandom event.

Cytogenetic characteristics of therapy-related acute nonlymphocytic leukaemia, preleukaemia and acute myeloproliferative syndrome: correlation with clinical data for 61 consecutive cases

Cytogenetic studies were performed on a new series of 23 patients with therapy-related acute non-lymphocytic leukaemia, preleukaemia or an acute myeloproliferative syndrome. In our total series of now 61 cases studied by chromosome banding techniques, at least one of the abnormalities -7, 5q-, 7q- or -5 or some related unbalanced translocations, primarily -7, +t(1q7p), was observed in 40 patients. The critical region for the deletions of chromosome no. 5 comprises bands 5q22 to 5q33 and of chromosome no. 7 bands distal to 7q22. The third most frequently involved chromosome was no. 21, rearranged at band 21q22 in the three patients with 21q+ and in one patient with 21q-. An i(21q) was observed in two patients, a -21 in four patients and a -22, +t(21q22q) and a -5, -21, +t(5p21q) in one patient each. Other characteristic abnormalities included total loss or rearrangements of the short arm of chromosome no. 17, observed in nine patients. One patient had a -12, three others had rearrangements resulting in a partial or total loss of the short arm of chromosome no. 12. A 19q+ with translocation to band 19q13 was observed in three cases, a -18 in three cases and a 3p- in four cases. Thirty-one patients with multiple chromosome aberrations experienced a significantly shorter survival as compared to 13 patients with a normal karyotype (P = 0.02) and 17 patients with one single chromosome aberration (P less than 0.01).

Chromosomal subclonal evolution in paroxysmal nocturnal hemoglobinuria evolving into acute megakaryoblastic leukemia

Four cytogenetic studies were performed in the course of a paroxysmal nocturnal hemoglobinuria evolving into acute megakaryoblastic leukemia. The clonal evolution was characterized by a unique structural change (9p) at the time of diagnosis, heralding an accelerated and complex karyotypic alteration including 5q-, 12p-, +21, -5, -7. At the terminal phase, the initial population was replaced within 1 week by a new overgrowing clone with -5, +8, +17. This suggests that the paroxysmal nocturnal hemoglobinuria-associated preleukemia and leukemic states share with acute nonlymphocytic leukemia the same nonrandom chromosomal changes.

Cytogenetic studies in 69 patients with myelodysplastic syndromes (MDS)

Cytogenetic studies were performed in 69 patients with myelodysplastic syndromes classified according to the FAB proposals. Overall incidence of chromosomal anomalies was 48% with 5q-, +8, 12p-,-7/7q- being the aberrations most often found. The 12p- chromosome showed a close correlation with a prior exposure to mutagenic agents and CMML. Although there were no group-specific cytogenetic anomalies, FAB classification strongly influenced their incidence. They were lower (36%) in RA/RA-S than in RAEB/RAEB-T/CMML (53%). Chromosomal anomalies were significantly more often found in patients with a prior exposure to carcinogenic agents (80%) than in unexposed patients (33%). The presence of chromosomal anomalies did not predict a higher risk of leukemic transformation.

Utility of the FAB classification for myelodysplastic syndromes: investigation of prognostic factors in 237 cases

The utility and prognostic significance of the FAB classification was studied in 237 patients with a myelodysplastic syndrome. No significant differences in actuarial survival and probability of transformation to acute leukaemia were found in patients with RA, AISA or CMML. The median survival time for the RA group was 50 months, for the AISA and CMML subclasses more than 60 months. The probability of transformation for the RA, AISA and CMML subgroups showed a linear trend with a probability of 25% for the RA, 16% for the AISA and of 18% for the CMML groups after a 5 year observation period. A uniformly poor prognosis was found for the RAEB and RAEB/t subgroups with median survival times of respectively 9 and 6 months. Chromosomal abnormalities were found in 68 out of 155 patients (44%). Patients with only normal metaphases or with abnormal metaphases together with karyotypic normal cells had a longer median survival time and a lower probability for transformation as compared to those with only abnormal metaphases. The most important factor in prognosis is the number of blast cells in blood and bone marrow. Age and sex, and certain quantitative and qualitative abnormalities in the peripheral blood appear of limited prognostic value for patients with RA, AISA and CMML. The longer life expectancy of 35 patients with CMML as compared to other series seems to be related to the percentage of blast cells at the time of diagnosis.

Late appearing 5q--marker in refractory anemia

A patient with myelodysplasia indistinguishable from the 5q--syndrome is described. No clonal chromosome abnormalities were detected in the total of 120 bone marrow cells initially examined. At the next sampling, 3 years later, del(5q) was present in all analyzed metaphases. These findings indicate that del(5q) may be only one of the pathogenetically important events in the 5q--syndrome, and that submicroscopic changes may precede the visible chromosomal rearrangement.

Deletion of the long arm of chromosome 5 (5q-) as a secondary event in the course of refractory anemia

A 54-year-old chemical plant worker developed mild pancytopenia, with normal bone marrow morphology. Normal bone marrow cytogenetics were documented. The patient developed worsening anemia 5 years into his course. The bone marrow morphology remained normal, but four of 30 bone marrow metaphases examined showed deletion of the long arm of chromosome #5. Eight years into his course, the patient developed severe thrombocytopenia, and his bone marrow became hypercellular, with dysplastic changes. Deletion of the long arm of chromosome #5 was seen in all of 21 bone marrow metaphases examined. There had been no new exposure to potential mutagens during the course of the patient's illness. The occasional documentation of the late appearance of cytogenetic abnormalities during the course of clonal hematopoietic disorders implies that, in some cases at least, chromosomal abnormalities may not be primary pathogenetic events. The full expression of clonal disorders may require several pathogenetic events, which may occur in variable order.

Nuclear bridging of erythroblasts in acquired dyserythropoiesis: an early and transient preleukemic marker

The clinical, hematologic, and histological characteristics of two patients who progressed from refractory anemia to acute leukemia are described. When first studied, nuclear bridging of erythroblasts, similar to that seen in congenital dyserythropoietic anemia type I and megakaryocytic dysplasia, were the only abnormalities. Within 6 years, both patients died, the first of acute nonlymphocytic leukemia, the second of erythroleukemia. Nuclear bridging of erythroblasts in the marrow of these patients was an early and transient phenomenon and was not observed during the terminal phase of leukemia.

Hematologic and cytogenetic remission of 5q-refractory anemia after syngeneic bone marrow transplantation

Refractory macrocytic anemia with hypolobulated megakaryocytic nuclei and partial deletion of the long arm of chromosome 5 has been termed the 5q- syndrome. Although long survival has been reported in a few cases of 5q- refractory anemia, accumulating evidence suggests that this syndrome is a preleukemic state with risk of transformation to acute nonlymphocytic leukemia as well as complications of bone marrow failure. This report describes the first apparently successful therapy for this disorder in a young man who originally presented with a clinical picture consistent with pure red cell aplasia and normal marrow chromosomes but with hypolobulated megakaryocytic nuclei. He was treated with vitamins, androgens, and sequential trials of immunosuppressive therapy, all without response. Two years after diagnosis, repeated marrow cytogenetic studies showed a 5q- abnormality in 70 percent and later in 100 percent of marrow metaphases. Because of transfusion-induced hemosiderosis and the availability of a cytogenetically normal monozygotic twin, bone marrow transplantation was undertaken. In light of the clonal (and suspected preleukemic) nature of the 5q- syndrome, the patient's marrow was ablated with a busulfan plus cyclophosphamide regimen used for patients with nonlymphocytic leukemia. Sustained engraftment of cytogenetically normal marrow ensued. Two years after transplantation, and following six months of regular phlebotomy, the patient was hematologically normal with a normal serum ferritin level.

Evidence for the involvement of GM-CSF and FMS in the deletion (5q) in myeloid disorders

By in situ chromosomal hybridization, the GM-CSF and FMS genes were localized to human chromosome 5 at bands q23 to q31, and at band 5q33, respectively. These genes encode proteins involved in the regulation of hematopoiesis, and are located within a chromosome region frequently deleted in patients with neoplastic myeloid disorders. Both genes were deleted in the 5q-chromosome from bone marrow cells of two patients with refractory anemia and a del(5)(q15q33.3). The GM-CSF gene alone was deleted in a third patient with acute nonlymphocytic leukemia (ANLL) who has a smaller deletion, del(5)(q22q33.1). Leukemia cells from a fourth patient who has ANLL and does not have a del(5q), but who has a rearranged chromosome 5 that is missing bands q31.3 to q33.1 [ins(21;5)(q22;q31.3q33.1)] were used to sublocalize these genes; both genes were present on the rearranged chromosome 5. Thus, the deletion of one or both of these genes may be important in the pathogenesis of myelodysplastic syndromes or of ANLL.

Chromosome abnormalities in acquired idiopathic sideroblastic anemia with subsequent leukemic transformation

Chromosomal abnormalities were demonstrated in the bone marrow cultures of two patients with acquired idiopathic sideroblastic anemia (AISA). Both patients subsequently experienced leukemic transformation and developed acute myelomonocytic leukemia (type M4). A review of the literature revealed that approximately 40% of the AISA cases manifest chromosomal abnormalities, of which 20.5% underwent leukemic conversion.