Karyotypic patterns and their clinical significance in polycythemia vera

A Novel Acquired t(2;4)(q36.1;q24) with a Concurrent Submicroscopic del(4)(q23q24) in An Adult with Polycythemia Vera

Background: Polycythemia vera (PV) is a clonal myeloid stem cell disease characterized by a growth-factor independent erythroid proliferation with an inherent tendency to transform into overt acute myeloid malignancy. Approximately 95% of the PV patients harbor the JAK2V617F mutation while less than 35% of the patients harbor cytogenetic abnormalities at the time of diagnosis. Methods and Results: Here we present a JAK2V617F positive PV patient where G-banding revealed an apparently balanced t(2;4)(q35;q21), which was confirmed by 24-color karyotyping. Oligonucleotide array-based Comparative Genomic Hybridization (aCGH) analysis revealed an interstitial 5.4 Mb large deletion at 4q23q24. Locus-specific fluorescent in situ hybridization (FISH) analyses confirmed the mono-allelic 4q deletion and that it was located on der(4)t(2;4). Additional locus-specific bacterial artificial chromosome (BAC) probes and mBanding refined the breakpoint on chromosome 2. With these methods the karyotype was revised to 46,XX,t(2;4)(q36.1;q24)[18]/46,XX[7]. Conclusions: This is the first report on a PV patient associated with an acquired novel t(2;4)(q36.1;q24) and a concurrent submicroscopic deletion del(4)(q23q24). The study also underscores the benefit of combined usage of FISH and oligo-based aCGH analysis in characterizing chromosomal abnormalities. The present findings provide additional clues to unravel important molecular pathways in PV to obtain the full spectrum of acquired chromosomal and genomic aberrations, which eventually may improve treatment options.

Significance of cytogenetic abnormalities in patients with polycythemia vera

We analyzed 133 patients with polycythemia vera (PV) who were followed at our institution (median 7.5 years) and had adequate cytogenetics information. The 5-, 10- and 15-year survival rates were 93%, 79% and 64%, respectively, with a median projected overall survival of 24 years. Nineteen patients (14%) had abnormal cytogenetics at any time during the disease course (no survival difference). Sixteen patients (12%) underwent disease transformation during follow-up, after a median of 8.5 years, to myelofibrosis (n = 11), acute myeloid leukemia (n = 4) or myelodysplastic syndrome (n = 1); eight had cytogenetic abnormalities. Among 133 patients, 39 were newly diagnosed: 33 with normal and six with abnormal cytogenetics (no survival difference); nine underwent disease transformation (six with normal and three with abnormal cytogenetics at diagnosis). In keeping with other smaller series, the presence of chromosomal abnormalities may have had a role in disease transformation in patients with PV; survival was not affected likely due to short follow-up.

Therapy-related patterns of cytogenetic abnormalities in acute myeloid leukemia and myelodysplastic syndrome post polycythemia vera: single center experience and review of literature

A minor fraction of patients with polycythemia vera (PV) develop a terminal acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Analysis of the cytogenetic abnormalities during AML or MDS may help in understanding if this development is part of the natural course of the disease or induced by myelosuppressive therapy. Thirty-six cases with AML or MDS post PV, collected in a single Swedish institution during a 33-year period, are described with special regard to time to development of AML or MDS, therapy given during active PV, and cytogenetic findings during AML or MDS. A further 118 cases of AML or MDS post PV, in whom type of therapy during active PV and cytogenetic findings during AML or MDS were reported, were collected from the literature. AML or MDS developed in our own series after 1-30 years with a fairly constant rate (two cases per year). The most frequent cytogenetic abnormalities were +1q, -5, 5q-, -7, 7q-, +8, +9, 11q-, 13q-, and 20q-. When patients in the total material (n = 154) were divided with regard to treatment during active PV, marked differences were observed. The highest frequency of abnormalities was found in patients given multiple lines of therapy (n = 61), dominating features being -5/5q- in 28 patients (46%), -7/7q- in 19 patients (31%), numerous translocations in 24 patients (39%), and unidentified markers in 22 patients (36%). Half of the patients treated with hydroxyurea alone showed a -5 or 5q- abnormality. In patients treated with phlebotomy alone, +8 and +9 were the most frequent findings. The type of therapy given during active PV influences the type of chromosome abnormalities present during terminal AML or MDS and can also be instrumental in the development of leukemia.

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.

Chromosomal anomalies in two coexistent myeloproliferative disorders

A 58-year-old male presented with fatigue, tiredness, and pruritus after hot showers and an elevated white blood cell count (20000/mm(3)). A diagnosis of polycythemia vera (PV) was made after investigation revealed a low erythropoietin and elevated leukocyte alkaline phosphatase (LAP) score; he was treated with repeated phlebotomies. Two years later he developed elevated white counts again and investigation revealed Philadelphia chromosome positive (19/20 cells) chronic myelocytic leukemia (CML). The karyotype also revealed trisomy 9 in 1 of 20 cells. He was treated with imatinib mesylate and went into clinical, hematologic, cytogenetic, and molecular remission. Repeat chromosomal analysis revealed absence of Philadelphia chromosome and BCR/ABL translocation but presence of trisomy 9. To our knowledge, this is the first reported case of coexisting PV and CML both associated with separate chromosomal abnormalities. This also raises an interesting therapeutic consideration of using concomitant imatinib mesylate and hydroxyurea.

Exploring polycythaemia vera with fluorescence in situ hybridization: additional cryptic 9p is the most frequent abnormality detected

Between 1986 and 2001, 220 patients with polycythaemia vera (PV) were studied using conventional cytogenetics. Of 204 evaluable patients, 52 (25.4%) had clonal abnormalities. The recurrent chromosomal rearrangements were those of chromosome 9 (21.1%), del(20q) (19.2%), trisomy 8 (19.2%), rearrangements of 13q (13.4%), abnormalities of 1q (11.5%), and of chromosomes 5 and 7 (9.6%). Subsequent analysis of 32 patients, performed at follow-up of up to 14.8 years, revealed new clonal abnormalities in five patients and the disappearance of an abnormal clone in four. Eleven patients remained normal up to 11.5 years and seven patients maintained an abnormality for over 10 years. Fifty-three patients were studied retrospectively using interphase fluorescence in situ hybridization (I-FISH), utilizing probes for centromere enumeration of chromosomes 8 and 9, and for 13q14 and 20q12 loci. Conventional cytogenetics demonstrated clonal chromosome abnormalities in 23% of these 53 patients. The addition of I-FISH increased the detection of abnormalities to 29% and permitted clarification of chromosome 9 rearrangements in an additional 5.6% of patients. FISH uncovered rearrangements of chromosome 9 in 53% of patients with an abnormal FISH pattern, which represented the most frequent genomic alteration in this series.

Comparative genomic hybridization in polycythemia vera and essential thrombocytosis patients

Polycythemia vera (PV) and essential thrombocytosis (ET) are clonal chronic myeloproliferative disorders originating from a multipotent stem cell. Bone marrow examinations reveal chromosomal abnormalities in 15-43% of PV patients and 5% of ET patients, but no specific recurring abnormality has been found to date. We aimed to find cytogenetic aberrations in PV and ET by comparative genomic hybridization (CGH), a relatively new molecular cytogenetic technique. In this study, CGH analysis was performed on peripheral blood leukocytes of 12 PV patients and 8 ET patients. One patient (8.3%) with PV had an abnormal karyotype with a deletion in 7q11.2 and one patient with ET (12.5%) had a gain in 18p. Peripheral blood analysis by CGH revealed a low frequency of cytogenetic abnormalities in PV and ET patients. However, using CGH we were able to detect two cytogenetic aberrations that were not reported previously in these disorders.

Molecular genetics and cytogenetics of myeloproliferative disorders

The myeloproliferative disorders are believed to represent clonal malignancies resulting from transformation of a pluripotent stem cell. X-inactivation patterns of peripheral blood cells have been proposed as a useful diagnostic tool but this method is limited by the finding of a clonal X-inactivation pattern in a significant proportion of normal elderly women. There is no pathognomonic chromosomal abnormality associated with the myeloproliferative disorders. However, consistent acquired cytogenetic changes include del(20q), del(13q), trisomy 8 and 9 and duplication of segments of 1q, all of which have been observed at diagnosis or before cytoreductive therapy and therefore represent early lesions which contribute to the pathogenesis of these disorders. Although, the acquired molecular defects underlying most myeloproliferative disorders have not yet been elucidated, translocations associated with the rare 8p11 syndrome have permitted identification of a novel fusion protein. The role of a number of candidate genes in the other myeloproliferative disorders has also been studied, but no mutations have been identified so far. It is likely that a number of genes will be involved, given the varied phenotypes of the diseases. Identification of causal genes will be of considerable interest to both clinicians, who currently lack a specific and sensitive diagnostic test, and scientists interested in fundamental issues of stem cell behaviour.

Childhood myeloproliferative disorders

Disorders classified as paediatric myeloproliferative disorders (MPD), such as juvenile chronic myeloid leukaemia (JCML), and as paediatric myelodysplastic syndrome (MDS), are essentially diseases characterized by abnormal myeloproliferation and they share similar genetic events on chromosome 7. As such, the abnormalities of increased myeloproliferation in childhood (AIMC) should be considered under the same heading. Constitutional and other genetic factors play an essential role in children and include the NF1 gene, whereas toxic exposure is of greater importance in adults. The most common cytogenetic alteration is that of monosomy or deletion of the long arm of chromosome 7. Critical regions have been identified and mapped by fluorescence in situ hybridization (FISH). It appears that the similar critical regions on chromosome 7 are involved, and suggests that these regions may contain genes important in the pathogenesis of AIMC.

A detailed physical and transcriptional map of the region of chromosome 20 that is deleted in myeloproliferative disorders and refinement of the common deleted region

Acquired deletions of the long arm of chromosome 20 are the most common chromosomal abnormality seen in polycythemia vera and are also associated with other myeloid malignancies. Such deletions are believed to mark the site of one or more tumor suppressor genes, loss of which perturbs normal hematopoiesis. A common deleted region (CDR) has previously been identified on 20q. We have now constructed the most detailed physical map of this region to date--a YAC contig that encompasses the entire CDR and spans 23 cM (11 Mb). This contig contains 140 DNA markers and 65 unique expressed sequences. Our data represent a first step toward a complete transcriptional map of the CDR. The high marker density within the physical map permitted two complementary approaches to reducing the size of the CDR. Microsatellite PCR refined the centromeric boundary of the CDR to D20S465 and was used to search for homozygous deletions in 28 patients using 32 markers. No such deletions were detected. Genetic changes on the remaining chromosome 20 may therefore be too small to be detected or may occur in a subpopulation of cells.

Translocation (1;20)(q32;q13.3) in myelofibrosis following polycythemia vera

We report a novel chromosomal translocation (1;20)(q32;q13.3) in a patient with myelofibrosis following polycythemia vera. This 73-year-old woman developed myelofibrosis 6 years after the initial diagnosis of polycythemia vera (PV). The course of PV was uneventful. Subsequent to the diagnosis, the patient was treated with phlebotomy and low doses of hydroxyurea for 4 years. No therapy was delivered during the remaining 2 years. A bone-marrow biopsy and a karyotype analysis performed because of evolving anemia demonstrated myelofibrosis and a chromosomal aberration-t(1;20)(q32;q13.3). Aberrations in chromosomes 1 and 20 have been reported in myeloproliferative disorders, but a t(1;20) translocation has not been reported. Because a karyotype analysis was not performed at the time PV was diagnosed, whether this translocation is linked to the primary disease (PV) or to the transition to myelofibrosis is not known.

The detection of trisomies 8 and 9 in patients with essential thrombocytosis by fluorescence in situ hybridization

Essential thrombocytosis (ET) is a clonal, chronic myeloproliferative disorder (MPD) originating from a multipotent stem cell. To date no specific cytogenetic marker has been found in ET. It was recently reported that chromosomal aberrations have been detected by fluorescence in situ hybridization (FISH) in patients with normal karyotypes or nonanalyzable metaphases. Therefore, we evaluated whether trisomies 8 and 9, which are commonly found in MPDs, can be detected in ET by FISH and compared the results with chromosome analysis. Peripheral blood mononuclear cells of patients with essential thrombocytosis were studied by classical chromosome banding and by FISH. We used biotin labeled alpha satellite of chromosome 8 and biotin labeled beta satellite of chromosome 9 as probes for the FISH studies. FISH detected 5 patients with trisomy 8 and 5 with trisomy 9 of the 18 patients evaluated. No trisomy was found by cytogenetic studies. The trisomies were detected by FISH in only a minority of the cells. No correlation was found between the presence of a trisomy and clinical characteristics. FISH is a sensitive method for the detection of trisomies 8 and 9 in patients with ET. The common finding of these chromosomal aberrations in MPD suggests that genes associated with myeloid proliferation are located on these chromosomes. Standardization of interphase cytogenetics is needed before this technique can be accepted for routine use in the clinic.

Derivative (y)t(Y;1)(q12;q12),+9 in a patient with polycythemia vera during transition into myelodysplasia

Cytogenetic analysis of bone marrow cells of a 63-year-old male Caucasian patient with polycythemia vera (PV) who developed anemia, thrombocytopenia, and increased granulocytic immaturity revealed a 47, X,der(Y) t(Y;1)(q12;q12),+9 karyotype. The breakpoint in chromosome 1 appeared to map to q12 and not to q21, as has been described in previous reports without FISH confirmation. In the 4 years before this transition the patient was polycythemic and, accordingly, treated with phlebotomy and three short courses of busulfan. The cytogenetic picture observed has been described before in seven patients: three with PV, three with myelodysplasia, and one with Fanconi anemia. In 5/7 cases, like in our patient, the abnormality was observed during transition of the disease into either myelodysplasia or AML.

The role of alpha-interferon in essential thrombocythaemia, polycythaemia vera and myelofibrosis with myeloid metaplasia (MMM): a concise update

Treatment of essential thrombocythaemia (ET), polycythaemia vera (PV), and myelofibrosis with myeloid metaplasia (MMM) patients is frequently a difficult issue. To date, there is no generally accepted treatment for these diseases which can reduce the risk of thromboembolism and/or haemorrhagic events, avoid any increase in the frequency of secondary myelofibrosis and terminal blast transformation and decrease the reticulin content in the bone marrow of MMM patients. The most frequently used myelosuppressive agent is hydroxyurea (HU), but widespread application has failed to demonstrate that is not leukaemogenic. In patients with MMM, conflicting results have been obtained following alpha-IFN treatment. Haematological responses have been seen in 50% of the patients. Usually the patients showing good responses had a hyperproliferative type of disease. In only one case was a reduction of reticulin content of the bone marrow observed. Thus, these findings do not indicate alpha-IFN as a first-line therapy. On the other hand, the results of several reports in ET and PV patients have shown a reduction in the abnormal proliferation of megakaryocytes and erythroid elements, following alpha-IFN treatment. A reduction in spleen size has also frequently been seen. Together with the improvement of haematological parameters, clinical symptoms have also responded positively. Long term control of these diseases can be obtained with a well-tolerated low dose of alpha-IFN. However, PV and ET are not usually characterized by cytogenetic abnormalities, making it very difficult to demonstrate the disappearance of clonal haemopoiesis following alpha-IFN therapy, even if this does occasionally occur, as evident from the two cytogenetic convertions described in the literature. As compared to myelosuppressive drugs or phlebotomy, alpha-IFN thus represents an attractive new treatment, able to exert a fundamental influence on these diseases, presumably without any untoward leukaemogenic or gonadotoxic activity.

Fluorescence in situ hybridization for the detection of trisomies 8 and 9 in polycythemia vera

Trisomies 8 and 9 are the most common numerical chromosome abnormalities in polycythemia vera (PCV). Their role in the pathogenesis of the disease is unclear, however, as is their diagnostic or prognostic value. We evaluated fluorescent in situ hybridization as compared to chromosome analysis for the detection of trisomies 8 or 9 in peripheral blood cells of PCV patients. We demonstrated that FISH is a more sensitive method for the detection of the abnormalities. A positive correlation between the duration of the disease and trisomy 9 was found. FISH is a sensitive, convenient, and rapid method for the diagnosis and follow-up of chromosome aberrations in patients with PCV. The application of FISH to a larger cohort of patients may provide valuable information regarding the role of the chromosomal aberrations in the initiation and progression of this disease.

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.

Chromosome 11 rearrangement at band 11q21 in a patient with essential thrombocythemia

A case of essential thrombocythemia with a partial deletion of the long arm of chromosome 11, del(11)(q21) as a sole chromosomal anomaly is reported. Rearrangement of chromosome 11 at band 11q21 has been reported in six patients with chronic myeloproliferative disorders: four with post-polycythemic myelofibrosis, one with myelofibrosis with myeloid metaplasia, and one with Ph+ chronic myeloid leukemia in blastic phase. Except for the last patient, all patients had been treated with 32P and/or an alkylating agent prior to cytogenetic examination. This is the first report of the 11q21 abnormality in essential thrombocythemia seen at diagnosis.

Chromosome studies in 104 patients with polycythemia vera

Chromosome studies were done in 104 patients with various stages of polycythemia vera (PV): 10 had leukemia-myelodysplastic syndrome, 28 had post-PV with myeloid metaplasia (PPVMM), 12 had PV with myelofibrosis, and 54 had PV. Chromosome studies were successful in 86 patients, 37 (43%) of whom had a chromosome abnormality. At diagnosis, 4 of 28 patients (14%) had an abnormal clone; the incidence was 78% in PPVMM and 100% in leukemia-myelodysplastic syndrome. Among the 63 patients with successful chromosome studies during the first 10 years of disease, 27% had an abnormal clone. In contrast, of the 23 patients who had the disease for more than 10 years, 87% had an abnormal clone. Chromosome abnormalities were found in 11 of the 60 patients who either were untreated or underwent only phlebotomy and in 26 of the 44 patients who were treated with myelosuppressive agents. Trisomy 8, +9, and 20q- were found in some patients early during the course of their disease and also among untreated patients. These chromosome abnormalities seem to be related to the natural course of PV rather than to therapy. Patients with a chromosomally abnormal clone at the time of diagnosis of PV had a poorer survival than did those with only normal metaphases. Cytogenetic results did not predict evolution of the disease, but they did provide clues to hematologic phenotype, duration of the disease, and consequences of myelosuppressive therapy.

Cytogenetic abnormalities and leukemic transformation in hydroxyurea-treated patients with Philadelphia chromosome negative chronic myeloproliferative disease

Eighty-one consecutive hydroxyurea-treated patients with Philadelphia (Ph) chromosome negative chronic myeloproliferative disease were followed prospectively from 1981 to 1989; 35 of them had polycythemia vera, 32 had essential thrombocythemia, 12 had myelofibrosis, and 2 had myeloproliferative syndromes. The 81 patients were treated with hydroxyurea for a total of 3,804 months during the observation time. Only three patients had been treated with alkylating agents or 32P before start of hydroxyurea treatment. Four patients transformed into acute myeloid leukemia or myelodysplastic syndromes; three of these patients had essential thrombocythemia, and one had a myeloproliferative syndrome. Two patients died of solid cancers. Five out of 53 evaluable patients (9%) had pretreatment clonal cytogenetic abnormalities involving chromosomes 1, 9, 20, and 21. At follow-up, during or after hydroxyurea treatment, 15% had cytogenetic abnormalities, an unexpectedly low frequency compared to the previously reported frequency in patients with polycythemia vera treated with alkylating agents. None of our patients who developed cytogenetic clonal changes during hydroxyurea therapy had polycythemia vera. However, follow-up is too short to draw any conclusions about the mutagenic potential of hydroxyurea compared to alkylating agents.

Leukemic transformation in polycythemia vera: analysis of risk factors

Forty-eight patients with polycythemia vera (PV) were retrospectively studied for incidence of acute leukemia over a 12 year period. Initial clinical features, hemogram, RBC mass, B12 levels, neutrophil alkaline phosphatase (NAP), and therapy given were studied for association with development of acute leukemia. There were 25 males and mean age at diagnosis was 61.4 years. Initial Hg was 18.38 +/- 1.86 g/dl, WBC 16.44 +/- 12.92 (x 1,000/mm3), platelets 632.94 +/- 303.81 (x 1,000/mm3), B12 1,030.93 +/- 445.20 pg/ml, and neutrophil alkaline phosphatase (NAP) score 136.63 +/- 55.14. Twenty-three patients were treated with phlebotomy alone and 25 received additional myelosuppressive therapy as follows--2 received p32 alone, 4 alkylating agents alone, 8 hydroxyurea (HU) alone, and 11 received 2 or more (multiple) of these agents. None of those treated with phlebotomy alone but 6 of 25 (24%) patients given myelosuppressive therapy developed acute leukemia (P = .03) after a mean period of 46.8 months from start of myelosuppressive therapy. Four of the 11 patients (36%) receiving multiple agent therapy developed acute leukemia (P = .019). Initial hemoglobin levels, but not the other clinical parameters, were significantly higher in patients who developed acute leukemia (P = .002), and this difference persisted in various subgroups receiving myelosuppressive therapy. Thus, high initial hemoglobin and use of any myelosuppressive therapy are associated with an increased risk of leukemic transformation in polycythemia vera. This risk becomes substantial with the use of two or more myelosuppressive agents. Since myelosuppressive therapy does not prolong survival, its role in the management of polycythemia vera should be reexamined.

Polycythemia vera. A clinical study of 141 patients

The clinical course of 141 unselected patients (64 m, 77 f, median age 59) with polycythemia vera (PV), treated during the period 1967 to 1986 was analyzed to study prognostic factors and the correlation between treatment strategies and complication rates. Therapy was performed according to a prospectively defined treatment protocol. Primary control of the disease was achieved by phlebotomy. Marrow suppression by radioactive phosphorus or low dose busulphan was used only as a second-line therapy or to lower high platelet counts. The clinical course of the patients was characterized by a low rate of acute leukemia (4%) and a high rate of thromboembolic complications (40%). Myelofibrosis developed in 17 patients (12%). Median survival of the patents was 9.4 years. The prognostic influence of several parameters at the time of diagnosis was tested: age, sex, spleen size, percentage of blood blasts + promyelocytes, leucocyte count, platelet count, hemoglobin, hematocrit, reticulocyte count and the values of the lactate-dehydrogenase (LDH) and the alkaline neutrophil phosphatase (ANP) all had no significant influence on the length of survival. The prognosis of PV patients with atypical disease presentation at diagnosis was not different from patients with typical disease.

der(1)t(1;9): a specific chromosome abnormality in polycythemia vera? Cytogenetic and in situ hybridization studies

Two patients with polycythemia vera and an extra der(1)t(1;9) chromosome are reported. In one patient this was found as the sole abnormality. The other patient originally presented with trisomy 9 but later developed an extra der(1) during the further course of the disease with disapperance of the extra chromosome 9. In situ hybridization studies on this latter patient proved that the centromere of chromosome 1 was involved in the formation of the derivative chromosome.

Trisomy 20 in acute myelogenous leukemia

A patient with acute myelomonocytic leukemia was found to have trisomy 20 in his bone marrow cells. The patient achieved a complete response to standard antileukemic therapy. The literature is reviewed in regard to this abnormality.

Polycythemia: evaluation and management

The approach to diagnosis and classification of patients with polycythemia is reviewed with presentation of general and specific guidelines for the management of patients with polycythemia vera, secondary polycythemia and relative polycythemia.

Acute lymphoblastic leukemia in a patient with longstanding polycythemia vera: cytogenetic analysis reveals two distinct abnormal clones

A 68-year-old female patient is described in whom acute lymphoblastic leukemia followed a long course of polycythemia vera. Chromosomal analysis of a peripheral blood specimen at the time of blastic transformation revealed two distinct clones: one characterized by a chromosomal abnormality frequently noted in polycythemia vera and the other by a rearrangement characteristically observed in lymphoid malignancies. These findings suggest the existence of two independent hematologic diseases: this phenomenon would not support the speculation from previous reports that lymphoproliferative disorders in patients with polycythemia vera arise from clonal evolution.

Preleukemic syndromes and other syndromes predisposing to leukemia

The myelodysplastic and myeloproliferative syndromes are syndromes in childhood that may precede leukemia. Clinical and biologic features are reviewed in this article. Although rare, they offer an unique opportunity to observe the evolution of leukemia and give clues that are helping us to understand the leukemogenic process.

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.

A chromosomal profile of polycythemia vera

One hundred four patients with a diagnosis of polycythemia vera and a variable period of follow-up had one or more cytogenetic investigations. Chromosome abnormalities were found in 13% of untreated patients, in 56% of cases treated with radioactive phosphorus (32P) or cytotoxic drugs, and in 85% of patients in which transformation of the disease had occurred. Nonrandom chromosome abnormalities found before treatment included +8, +9, 13q-, 20q-; their prognostic value is little, as they are often associated with longstanding, stable disease. In contrast, 5q- anomaly and the appearance of subclones in patients with an abnormal karyotype were found to be poor prognostic signs, as they are usually coincidental with evolution of the disease to myelofibrosis or leukemia. Chromosomally two patterns of acute leukemia were observed in polycythemia vera patients. The first type resembles de novo acute leukemia, in that the clinical and cytologic characteristics of the disorder are easily defined by FAB criteria and the chromosome changes compatible with the types usually found in those conditions. In the second type, assignment to a FAB morphologic subgroup was more difficult, myelodysplastic changes were often present, and the karyotype showed complex abnormalities frequently involving chromosomes #5 and #7. All these features suggest the occurrence of secondary leukemia.

Trisomy 1q in polycythemia vera and its relation to disease transition

Clinical and cytogenetic details of 12 patients with polycythemia vera and complete or partial trisomy of the long arm of chromosome 1 are reported. All patients had trisomy for at least the segments 1q22 to 1qter. The 1q or material from 1q was translocated to another chromosome in eight patients. This was chromosome 9 in four patients, and those cases all had trisomy also for 9p. The trisomy 1q was found at the time of diagnosis in three patients, later during the polycythemic phase in five, and in four patients when they were first examined during a late stage of the disease. Acute leukemia or a myelodysplastic syndrome developed in eight of the 12 patients. Signs of advanced disease, eg, myeloid metaplasia or myelofibrosis, preceded the leukemia in four cases and was noted in one more patient. Trisomy 1q was the most frequent structural chromosome abnormality in patients with polycythemia vera. It is thus one of several nonrandom abnormalities that can appear at any stage of the disease. It seems to occur with higher frequency in patients with myelofibrosis and/or leukemia, but it is not a specific characteristic of these complications.

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.

The 5q-anomaly

A deletion of the long arm of chromosome #5 (5q-) occurs nonrandomly in human malignancies. As a rule, the deletion is interstitial; the distal breakpoint by conventional techniques is usually in band q32, the proximal breakpoints in q12 or q14. Variant breakpoints occur in less than 10% of all cases. As the sole anomaly, 5q- is characteristically found in refractory anemia with or without excess of blasts. It can occur as the sole anomaly in de novo or secondary acute nonlymphocytic leukemia, but is usually accompanied in those disorders by other chromosome changes that are also nonrandomly distributed. In addition, it can be found in lymphoproliferative disorders, and occasionally, also in solid tumors. The 5q- myelodysplastic syndrome typically occurs in older age groups, particularly in females. Characteristic features are macrocytic anemia, normal or elevated platelets in the presence of megakaryocytic anomalies, and a mild clinical course. In cases with 5q- only, transformation into ANLL occurs rarely. Additional chromosome anomalies and male sex are prognostically unfavorable signs. Sex ratio is also at the disadvantage of females in de novo 5q- ANLL, and the latter disorder can occur without being preceded by a myelodysplastic phase. A myelodysplastic phase usually precedes 5q- secondary leukemia, in males as well as in females, and additional chromosome anomalies, especially of chromosome #7, are almost invariably present in those cases. We conclude that 5q- is the most frequently occurring single chromosome anomaly in secondary leukemia. Furthermore, the resemblance between de novo and secondary 5q- MDS and ANLL is striking; clinically, as well as cytogenetically, they are indistinguishable, suggesting that all de novo cases may be due to environmental (chemical) carcinogens. Response to treatment and prognosis are very poor with current therapeutic regimens in de novo as well as in secondary 5q- ANLL. Morphologically, these ANLLs fall into all FAB categories. There is considerable evidence to show that the 5q- anomaly occurs in a myeloid precursor stem cell. The occasional occurrence in lymphoid malignancies, of B cell as well as T cell type, suggests that, as in Ph-positive disorders, a common progenitor stem cell may be affected in 5q- also. The 5q- lymphoid malignancies, however, are much more rare; it is not clear at the present time whether or not a 5q- counterpart of Ph-positive ALL exists, and mixed lymphoid-myeloid 5q- disorders have not yet been documented.(ABSTRACT TRUNCATED AT 400 WORDS)

The pattern and clinical significance of karyotypic abnormalities in patients with idiopathic and postpolycythemic myelofibrosis

Six of eight (75%) patients with postpolycythemic myelofibrosis (PPMF) and 11 of 20 (55%) patients with idiopathic myelofibrosis (MF), seen at the University of Chicago, had abnormal karyotypes in cells of bone marrow origin. The specific chromosomal findings and their clinical significance in these patients were analyzed. A review of the literature added the findings from abnormal karyotype studies in 10 patients with PPMF and 36 patients with MF to this series. The demonstration of an increased frequency of cytogenetic abnormalities after cytotoxic therapy in polycythemia vera (PV) implies that such therapy may have a role in the development of chromosomal changes seen in treated PV and PPMF. The cytogenetic abnormalities in MF appear to be unrelated to therapy except possibly for an association with partial or complete losses of chromosome 5 or 7. Trisomy 8 is the only finding that is more common in MF than in PPMF. Other abnormalities were more common in PPMF, particularly 20q-, loss of 7 or 7q-, and trisomy 9, and to a lesser extent trisomy 1q and 5q-. Cytogenetic abnormalities do not show a pattern that can be used to distinguish between PPMF and MF, nor are they useful in the prognosis of MF or in initial studies in PPMF. PPMF does appear to have a higher tendency toward leukemic transformation than does MF, and an evolution in karyotype appears to have serious prognostic implications in PPMF in regard to this transition.

Translocation 1;7 in dyshematopoiesis: possibly induced with a nonrandom geographic distribution

Eight patients with various hematologic disorders had an identical chromosomal aberration in their bone marrow or unstimulated peripheral blood, a translocation t(1;7) interpreted as t(1;7)(p11;p11). The translocation chromosome replaced one normal chromosome #7; therefore, the karyotype of the abnormal cells was trisomic for 1q and monosomic for 7q. Including four cases from the literature, a total of 12 patients (4 women, 8 men) with this translocation are known at the moment. The translocation does not seem to be associated with a specific disorder, but almost all patients had a preleukemic syndrome during some stage of their disease. It is very remarkable that 11 of the 12 patients lived in the Netherlands, and 7 patients had a history of iatrogenic exposure to alkylating agents or irradiation; one patient was a radiation worker and another one had a history of toxic exposure to chloramphenicol. It is suggested, therefore, that the t(1;7) is a possibly induced chromosomal aberration with a clearly nonrandom geographic distribution.

Chromosome studies in polycythemia vera patients

One hundred thirty-five polycythemia vera (PV) patients (30 untreated by chemotherapy and 105 treated) were studied cytogenetically . The incidence of clonal chromosomal abnormalities was 20.7% (28 patients in nonleukemic phase). The incidence of 20q - was 3.7% (5 patients). The presence of cytogenetically abnormal clones did not allow prediction of the evolution of the disease. In a few cases, abnormal clones disappeared at the time of later studies. Although nonrandom, the majority of clonal chromosomal abnormalities are believed to be secondary events in PV patients.

Hematologic manifestations associated with deletions of the long arm of chromosome 20

We investigated 20 patients with hematologic disorders who had a clone of cells with a deletion of most of a chromosome #20 long arm (20q-) in the bone marrow. Three patients had polycythemia vera (PV), 6 had acute nonlymphocytic leukemia (ANLL), 8 had preleukemia (PL), and 3 had other myeloproliferative disorders. In our laboratory, a 20q- chromosome is found in 6% of patients with PV, 3% of patients with ANLL, and 1% of patients with PL. Among the 6 patients with ANLL and a 20q- abnormality, 3 had erythroleukemia. There were no apparent clinical differences among our patients with 20q- chromosomes compared with other patients with similar disorders who did not have a 20q- chromosome. The breakpoint of the 20q- anomaly, in each instance, was in band 20q11, but it occurred near the centromere at 20q1101 in 16 patients and at the distal part of this band at 20q1109 in 4 patients. Three of the 4 patients with a breakpoint at 20q1109 had PL.

Cytogenetic studies on acute nonlymphocytic leukemias following polycythemia vera

Chromosome studies were performed on 15 patients suffering from acute nonlymphocytic leukemia (ANLL) and in one patient in a preleukemic state following polycythemia vera (PV). Clonal chromosome abnormalities that were present in all cases were clearly nonrandom and involved chromosomes #1, #5, #7, #8, #9, #11, and #21. A subdivision of ANLL into two categories occurring in the course of PV is proposed from the clinical, hematologic, and cytogenetic data: one resembling de novo ANLL with rapid initial evolution, easy classification into one group of the FAB nomenclature, and simple chromosome abnormalities; the other resembling induced leukemia, often with more progressive initial evolution, difficulty or impossibility of classification into one group of the FAB nomenclature, and complex chromosome abnormalities. The consequences for the commitment level of progenitor cell from which the leukemic clones originate are discussed.

Acquired partial deletions of the long arm of chromosome 5 in hematologic disorders

We have analyzed the data on 105 patients reported with a deletion of part of the long arm of chromosome 5 in the presence of hematologic disease. The major conditions associated with this abnormality are refractory anemia, polycythemia vera, and acute myelogenous leukemia, as well as the occasional occurrence of several other problems.

Karyotypic progression in human tumors

Karyotypic progression may be viewed in at least two ways. One approach seeks evidence for increasing and progressive deviation from the normal chromosome pattern in tumors. The clearest examples, found in some leukemias, are those in which successive karyotypic changes are superimposed on an already aberrant cell population. Evidence of chromosomal progression within solid tumors is far less frequent, possibly because the tumors themselves are at a relatively late stage in their evolution. An alternative approach, therefore, attempts to correlate the extent of karyotypic deviation with other aspects of tumor progression. Recent data, based on classical cytogenetic analyses and flow cytometry, are presented to determine relationships between karyotype and specific origin and morphology of tumors. The predominant theme which emerges, not surprisingly, is that the more deviant chromosome patterns are associated with other measures of increased biologic malignancy. What is surprising is the degree to which these properties are expressed in primary tumors and the relative lack of evidence for further karyotypic evolution with recurrence or metastasis. Examples of genetic instability, evolution through polyploidy, gene amplification, and selection for specific chromosomal rearrangement are found in populations of premalignant and malignant human cells. There is increasing recognition of the importance of tumor-specific chromosome aberrations in the stepwise progression from the normal to the fully neoplastic cell.