The Karyotype in Refractory Anaemia and Pre-leukaemia

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.

Acute leukemia characterized by trisomy 8 in Down's syndrome

Of the myeloproliferative disorders which develop in Down's syndrome, acute leukemia associated with trisomy 8 has distinct characteristics. It is non-lymphoblastic in type and has a preleukemia phase in which thrombocytopenia is a prominent feature. One case occurring in a 20 mth-old girl is reported and 3 other similar cases reviewed. Acquired trisomy 8 in Down's syndrome is linked to leukemogenesis and confers non-lymphoblastic differentiation.

Postleukemic dysmyelopoiesis

The morphologic and clinical features of four patients who developed significant bone marrow and blood dyspoiesis after successful chemotherapy for acute nonlymphocytic leukemia (ANLL) are described. This postleukemic dyspoiesis developed 1-6 months after leukemia induction therapy and persisted for 5-20 months in a relatively stable state. This period of prolonged dyspoiesis was not associated with rising myeloblast counts or clinical evidence of relapse. Dyspoietic abnormalities developed while two patients were receiving maintenance chemotherapy; the other two patients received no maintenance therapy. The dyspoietic changes in these four patients greatly exceeded those noted in a control group of ANLL patients on maintenance chemotherapy. The morphologic features of postleukemic dysmyelopoiesis were similar to those described in preleukemic dysmyelopoietic disorders. Erythroid abnormalities included hyperplasia with ring sideroblasts, megaloblastic changes, and cytoplasmic PAS reactivity. Myeloid abnormalities consisted of left-shifted granulopoiesis with hyper- and hyposegmentation; megakaryocytic abnormalities included hyperplasia with a predominance of hypolobulated forms. Three of the four patients eventually suffered relapse and have died. The fourth patient died of sepsis after 20 months of pancytopenia and dysmyelopoiesis. Theories to explain the development of postleukemic dysmyelopoiesis are presented which emphasize the possibility of drug-induced leukemia cell differentiation. Cytogenetic studies will be necessary to establish any relationship between ANLL and the subsequent postleukemic dysmyelopoiesis.

Dysmyelopoietic syndromes. A search for prognostic factors in 193 patients

Dysmyelopoietic syndromes cover sideroblastic or nonsideroblastic refractory anemia with or without excess of blasts, subacute or chronic myelomonocytic leukemia. The evolution of 193 patients was studied with regard to the initial hematologic picture. A certain number of variables of prognostic value have then been isolated: excess of marrow blasts (more than 5%); presence of circulating blasts or karyotypic anomalies; reduction in the number of polymorphonuclear leukocytes (less than 1.043 10(9)/l, of monocytes (less than 0.136 10(9)/l), of platelets (less than 140 10(9)/l), of in vitro granulopoietic progenitors (less than 5 per 10(5) nucleated cells plated), of erythrocytic incorporation of 59Fe at day 14 (less than 12%), of hemoglobin level (less than 92 g/l); previous exposure to radiation or chemotherapy; early hemolysis in 51Cr-labeled erythrocytes study; marrow heterogeneity in histology; less than 20% of ringed sideroblasts. The correlation between these variables and adjustments related to the length of survival and the order of magnitude of the critical level of the log-rank test show that the most significant variables in descending order are: excess of marrow blasts, neutropenia, thrombopenia, presence of circulating blasts, the type of erythropoietic insufficiency, and decrease of in vitro growth.

Use of bone-marrow culture in prediction of acute leukaemic transformation in preleukaemia

Bone-marrow granulocyte-macrophage progenitor cell proliferation and regulatory factor (colony-stimulating activity; CSA) production were assessed at presentation and, if possible, subsequently in twenty-one patients with dysmyelopoiesis and less than 5% bone-marrow blasts. Seven patients underwent acute leukaemic transformation 1-35 months after the first marrow culture. Assay of bone-marrow endogenous CSA proved the most useful prognostic test. The rate of transformation in the seven patients with raised CSA at presentation was significantly greater (five transformed and one died at or before 4 months) than that in the fourteen patients with normal, low, or undetectable CSA (two transformed at 27 and 35 months). In one of the latter an increase in bone-marrow CSA occurred 6 weeks before transformation (serial marrow samples were not available in the other case). No other marrow culture feature measured, including the presence or absence of granulocyte-macrophage colony-forming cells and total clone numbers (colonies and smaller clusters) was as useful.

Specific fine chromosomal defects in cancer: an overview

More than 2 tumors have been found to have a specific chromosomal abnormality. In acute nonlymphocytic and acute lymphocytic leukemia, subgroups have also been identified with consistent chromosomal defects and different prognoses and responses to treatment. With the recent advent of high resolution chromosome technology, it appears possible that most malignant tumors will be found to have a chromosomal defect. This has recently been observed in acute nonlymphocytic leukemias. These findings and the availability of new solid tumor techniques make it possible to predict that study of chromosomes in cancer will become a useful if not essential tool in the subclassification and understanding of the etiology of neoplasias.

Preleukemias

A chromosomally abnormal clone is demonstrable in the bone marrow of a significant number of patients with hemic disorders that carry an increased risk for the subsequent development of leukemia. These "preleukemia" states include a variety of cytopenias, myeloproliferative disorders, and childhood syndromes. The cytogenetic alterations that occur nonrandomly in these dyscrasias are often similar to those observed in acute nonlymphocytic leukemia and in the accelerated phase of chronic granulocytic leukemia: monosomy for chromosome 7; trisomy for 8,9,21, and the long arm of 1(1q); deletions of 5 and 20 (5q-, 20q-); and an isochromosome derived from 17 (iso 17q). These findings support the view that despite clinical differences, these various preleukemic disorders are all characterized by the presence in the hematopoietic tissues of a clone of cells derived from an altered hemic stem cell. Furthermore, the data suggest that preleukemia, chronic leukemia, and acute leukemia may be fundamentally similar diseases, differing primarily in the rate at which the aberrant clone is expanding. Chromosome studies may be of prognostic value in the cytopenic preleukemias. Patients with abnormalities show a decreased survival and are at increased risk for progression to acute nonlymphocytic leukemia. In the myeloproliferative disorders and the preleukemic childhood disorders, cytogenetic alterations are not clearly predictive, and aberrant clones may persist for years without clinical progression.