Cytogenetic studies in haematological disorders which may terminate in acute leukaemia

Isochromosome 17q in a case of myelofibrosis with myeloid metaplasia terminating in blastic transformation

A case of myelofibrosis with myeloid metaplasia in a 61-year-old female patient is reported. Cytogenetic studies were performed using short-term culture without phytohemagglutinin. A chromosomal aberration of an isochromosome 17q, [i(17q)], was revealed in 88% of the metaphases of peripheral blood cells in the blastic phase. However, all metaphases of bone marrow cells in the chronic phase showed a normal karyotype. Furthermore, i(17q) was also observed in 10% of the metaphases of spleen cells examined 8 months before blastic transformation. In this case, therefore, the cells with i(17q) were associated with an abnormal clone of blastic transformation, with the abnormal clone originating in the spleen with myeloid metaplasia.

Chromosome aberrations and prognosis in preleukaemia

24 patients with preleukaemia were cytogenetically studied by the G-banding staining technique. All patients developed later frank acute non-lymphocytic leukaemia and died. 13 patients had a completely normal karyotype (NN-patients) with a median survival time of 8 months. 6 patients had both normal and abnormal metaphases (AN-patients) with a median survival time of 18.5 months, while 5 patients had abnormal metaphases only (AA-patients) with a median survival time of 3 months.

[A prospective study on course and prognostic criteria in "preleukemia" (author's transl)]

The natural course of disease was followed in 33 patients with so-called preleukemia by a prospective multicentric protocol. Patients with the following criteria were included: Anaemia with granulocytopenia and/or thrombocytopenia, normal or increased cellularity of the bone marrow and exclusion of a known diagnosis of underlying disease. Follow up after assumption of "preleukemia" was 3 years or more. Median survival was 26 months after diagnosis of preleukemia and 36 months after the first unequivocal symptoms of the blood dyscrasia. 40% of the patients changed to the picture of leukemia within 2 years. The most important parameters suggesting subsequent transition to overt leukemia where chromosomal abberations and an increased blast count of the bone marrow.

Chromosome studies in preleukemic states. IV. Myeloproliferative versus cytopenic disorders

The prognostic value of marrow chromosome studies was examined in 112 "preleukemic" patients followed for at least one year or until death. Based on recent definitions, 49 patients were classified as myeloproliferative disorders (MPD) (polycythemia vera, myelofibrosis, undifferentiated myeloproliferative disorder, essential thrombocythemia), and 58 as cytopenic states (refractory anemia, pancytopenia). In each group, approximately one-third had a chromosomally-abnormal clone. For MPD, this had little predictive value, but in the cytopenias, 77% with a cytogenetic abnormality developed leukemia versus 39% without. Twelve cytopenic patients had multiple alterations involving more than 2 chromosomes and 11 died within 6 months, 9 with leukemia. Such patients may warrant consideration for aggressive chemotherapy before the appearance of clinical leukemia. Banding studies did not reveal any specific chromosome abnormalities consistently associated with these various preleukemic disorders, or with progression to leukemia, but nonrandom alterations were noted involving chromosomes 1, 5, 7-9, and 20 in the MPD group, and chromosomes 6 and 16 in the cytopenic patients. Correlation of these data with other reports indicates that certain cytogenetic abnormalities involving specific segments of the human genome confer a selective growth advantage on hemic clones which may present clinically as either preleukemia or leukemia.

A new chromosome abnormality in idiopathic sideroblastic anemia: 46,XY,del11q23

A new marker chromosome, deletion 11q23, was observed with the Giemsa banding technique in the bone marrow of a patient with idiopathic sideroblastic anemia. The abnormality was not detectable in the peripheral blood or with nonbanded chromosome studies. Nineteen of 40 cases of this disorder studied and reported to date had chromosomal aberrations, although the majority had only nonbanded karyotypes performed. This apparently high incidence of chromosomal defects and the finding in the present case indicate that more banded-karyotype analyses are needed to assess the presence of possible nonrandom cytogenetic changes in idiopathic sideroblastic anemia.

Chromosome studies in "preleukemia". III. Myelofibrosis

Cytogenetic studies were done on 18 patients with myelofibrosis or the closely related syndrome, undifferentiated myeloproliferative disorder (MPD). Clones of cells with chromosome abnormalities were demonstrated in the blood of eight individuals, including two with a history of radiation therapy and two with "acute myelofibrosis". Trisomy 8 was present in the latter two patients, but otherwise, there was no consistent cytogenetic pattern or correlation with specific hematologic findings. Sixteen of these patients have been followed for more than 1 year or until death; none has progressed to leukemia. The results indicate that chromosome abnormalities are relatively common in this disorder, but as with polycythemia vera, and unlike some other "preleukemic" states, the aberrant clones in myelofibrosis do not appear to indicate that clinical leukemia is imminent.

Blastic phase of agnogenic myeloid metaplasia simulating malignant lymphoma

A patient with angogenic myeloid metaplasia in blastic transformation with unusually prominent lymphadenopathy simulating lymphoma is described. Interestingly, the initial evidence of myeloblastic transformation was present in the lymph nodes but not in the marrow. Serial bone marrow biopsies showed fibrosis throughout the course of the disease, in spite of a gradual increase in the percentage of peripheral blood myeloblasts. Aneuploidy with a marker chromosome and a Philadelphia-like chromosome was present in the lymph node, bone marrow, and peripheral blood cells. The literature is reviewed regarding the incidence of prominent lymphadenopathy and chromosome abnormalities in agnogenic myeloid metaplasia and other myeloproliferative disorders.

Cytogenetic studies in sideroblastic anemia

Cytogenetic studies were performed on bone marrow aspirates from seven patients with acquired sideroblastic anemia. In one male patient a 45,X cell line was present in each of three bone marrow aspirates. The remaining six patients had a normal chromosome complement. The abnormal stem line in the bone marrow may be unrelated to the hematologic disorder or may indicate a neoplastic process still latent. The cytogenetic literature on sideroblastic anemia is reviewed.

Drug-induced anaemias

Many drugs have been reported to have caused anaemia. The most serious form involves marrow aplasia, but the way in which this is produced is not understood. A number of drugs lead to megaloblastic anaemia and where this is caused by interference with dihydrofolate reductase the explanation is obvious. However, some substances, notably anticonvulsants, cause megaloblastic anaemia by some other mechanism. A number of drugs cause intestinal bleeding with anaemia as a result. Sideroblastic anaemia is a relatively rare condition, sometimes caused by drugs, particularly those used in the treatment of tuberculosis. Leukaemia very occasionally supervenes in patients with drug-induced aplastic anaemia.