Small F chromosome in myelo- and lymphoproliferative diseases

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.

Anomalies of the long arm of chromosome 11 in human myelo- and lymphoproliferative disorders. I. Acute nonlymphocytic leukemia

In a series of 365 consecutive ANLL cases of which 45.1% had abnormal karyotypes, 13 cases were detected with a structural abnormality of the long arm of chromosome 11. Besides one isochromosome 11q, there were six deletions and six translocations. Of these 12 patients, seven had acute monocytic leukemia (FAB-type M5), two had an M4, two had an M2, and one case of secondary leukemia had an M3-like disorder. Similar results with regard to the type of leukemia were obtained upon analysis of 41 cases of ANLL with an 11q anomaly described in the literature. This study confirms that a high proportion of acute monocytic leukemias and a lesser proportion of acute myelomonocytic leukemias are characterized by an 11q anomaly, mostly involving bands q22 and/or q23. Acute monocytic leukemia with an 11q structural anomaly appears to have a poor prognosis.

Acute non-lymphocytic leukemia and acute myeloproliferative syndrome following radiation therapy for non-Hodgkin's lymphoma and chronic lymphocytic leukemia: cytogenetic studies

Seven cases of acute nonlymphocytic leukemia (ANLL) and one of malignant myeloproliferative syndrome were identified from a pool of 189 cases of non-Hodgkin's lymphoma (NHL) and CLL treated primarily with extensive radiotherapy at the Clinical Center, the National Institutes of Health. Four patients also received chemotherapy, two for only short periods. The median time interval from the diagnosis of the primary malignancy to the development of leukemia was 61 months (range 33 to 98 months) and the median survival after the diagnosis of leukemia was two months (0 to 9 months). All eight patients were cytogenetically abnormal and serial chromosome studies revealed that hypodiploidy was the most commonly observed chromosomal abnormality. Abnormalities of chromosome no. 7 were seen in all five patients analyzed by the chromosome banding technique; four of them had monosomy 7. The next most frequently involved chromosome was no. 5. The complexity, extensive nature, and long duration of the cytogenetic abnormalities prior to the diagnosis of leukemia in these patients may be characteristic of secondary leukemia in radiation-treated lymphoma and the presence of such anomalies may predict leukemic transformation.

Acute nonlymphoblastic leukemia in childhood

Cytogenetic studies have been done on a group of childhood patients over a period of 3 1/2 years in which time Giemsa trypsin banding was applied to all specimens. Fifteen of the 107 patients (14%) were diagnosed as having acute nonlymphoblastic leukemia (ANLL). Twelve of the 15 had chromosomal abnormalities. The most common was an involvement of the No. 7 chromosome which occurred in five patients. Three patients had trisomy 19. No correlation could be found between the disease subgroup and the karyotypic aberration in patients with anomalies involving a common chromosome.

Cytogenetic studies of chronic myelocytic leukemia in children and adolescents

In a 3 1/2 year cytogenetic study of 107 leukemia patients diagnosed in childhood and adloescence, 8 presented with chronic myelogenous leukemia (CML). Seven of the 8 had chromosomal abnormalities. Six had the Ph1 chromosome; 5 had the usual 9;22 translocation. Two patients had involvement with chromosome 15; one had a 9;15 translocation in Ph1 positive cells during remission while a second had a 1;15 translocation during blastic crisis. The 2 patients who did not have a Ph1 chromosome survived 13 and 30 months, respectively, considerably less time than the 4+ year survival in most of those with Ph1 positive CML.

Chromosome deletion [46,XX,del(20)(q11)] in agnogenic myeloid metaplasia

A woman in the fourth year of agnogenic myeloid metaplasia was found to have partial deletion of the long arm of chromosome 20 [46,XX,del(20)(q11)] in mitoses of presumably immature myeloid cells from unstimulated cultures of peripheral blood and bone marrow. Cytogenetic studies of peripheral blood lymphocytes showed a normal female karyotype.

Chromosome studies in polycythemia vera

Polycythemia vera (PV) represents an apparent monoclonal stem cell proliferation with a frequent transition to full neoplastic behavior. Up to 26% of untreated PV patients can be expected to have some chromosome abnormalities in the marrow at the time of diagnosis, and 10--15% have an abnormal cell line or clone. Both structural and numerical aberrations occur. Aneuploidy is the most common type of chromosome abnormality, however, with hyperdiploid clones occurring more frequently than hypodiploid clones. Chromosomes 1, 8, 9 and 20 are involved in a non-random pattern, and aberrations of all the F group, or at least the No. 20 chromosome seem to be associated to some extent with diseases involving erythroid hyperplasia. Leukemia develops in a certain percentage of patients regardless of the type of treatment they have received, but the relationship, if any, between the chromosome abnormalities and the development of leukemia is still uncertain. The abnormal clones that occur in PV appear to be quite stable and there is no indication at this time that they correlate with a prognosis of leukemic transformation.

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.