A. Louwagie

A new chromosome anomaly in acute lymphoblastic leukemia (ALL)

SummaryA new chromosome anomaly in acute lymphoblastic leukemia (ALL) is reported. Three, possibly four, patients showed an identical karyotype anomaly, characterized by a (4;11)(q13;q22) reciprocal translocation. This anomaly has not so far been found in lymphoproliferative disorders other than ALL. Two of the patients had congenital leukemia, but the anomaly described appears to be more characteristic of ALL than of congenital leukemia, and may help the clinician in establishing the diagnosis of ALL.

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.

Further characterization of morphologically defined typical and atypical CLL: a clinical, immunophenotypic, cytogenetic and prognostic study on 390 cases

We analysed a group of 390 patients, diagnosed with chronic lymphocytic leukaemia (CLL). Cases were subclassified as morphologically typical and atypical CLL according to the criteria of the FAB proposal. Typical CLL cases were mostly diagnosed at a low‐risk stage (Binet A/Rai 0), required no immediate treatment and expected a long survival; atypical CLL cases mostly presented at a more advanced risk stage (Binet B/Rai I–II), usually required immediate treatment and their survival was shorter. Moreover, clinical staging was of prognostic significance in typical but not in atypical cases.  In typical CLL, del(11q) was the most common chromosomal abnormality (21%) whereas in atypical CLL trisomy 12 was found in about 65% of the cases documented with an abnormal karyotype. Although chromosomal abnormalities were associated with a poor survival in typical CLL, they are of no prognostic significance in atypical CLL.  Based on these data, we conclude that subtyping CLL by morphology enables the identification of two groups of cases, each characterized by a specific clinical presentation, different cytogenetic abnormalities and prognostic parameters. We speculate that these two groups may represent two related, but different, diseases with different prognostic parameters and a different survival.

Trisomy 12 is uncommon in typical chronic lymphocytic leukaemias

The incidence of trisomy 12 was studied by conventional chromosome analysis in 111 patients referred as B‐cell chronic lymphocytic leukaemia (B‐CLL). Fluorescent in situ hybridization (FISH) was also applied in 34 of those patients with either a normal karyotype or no analysable mitoses. By karyotyping, trisomy 12 was present in 11.7% (13/111), whereas additional FISH increased the incidence to 14.4% (16/111). When subdividing our cases in either typical CLL (n= 90), fulfilling the FAB classification criteria, or atypical CLL (n= 21), with one or more variations from those criteria, the incidence of +12 by metaphase analysis was 3% and 48%, respectively. Additional FISH increased the incidence to 4% and 57%. The most common aberration in atypical CLL was FMC7 positivity (n= 11), followed by CD5 negativity (n= 8), strong surface immunoglobulin staining (n= 7) and atypical morphology (n = 6). Trisomy 12 could only be demonstrated in a small proportion of neoplastic cells in all positive cases. By FISH and/or karyotyping, all available samples at diagnosis of the disease were positive.

Morphologic, immunologic and cytogenetic studies in erythroleukaemia : evidence for multilineage involvement and identification of two distinct cytogenetic-clinicopathological types

Summary. Clinical features, as well as morphology, immunophenotype and cytogenetics were retrospectively studied in 20 patients with an original diagnosis of erythroleukaemia (EL) reclassified according to the FAB criteria. Fifteen patients had de novo EL, five patients had therapy‐related EL. Myelodysplasia preceded the onset of EL in eight cases and myelodysplastic features involving multiple haemopoietic lineages were observed at leukaemia presentation in all cases. Immunologic findings confirmed multilineage involvement, showing sub‐populations of cells expressing platelet‐associated markers in more than 50% of cases tested and the presence of a myelomonocytic component, besides glycophorin A‐positive cells. Cytogenetically, major karyotype aberrations (MAKA), defined by the presence of three or more aberrant events in the same clone, were observed in 14 cases, minor karyotype aberrations (MIKA) were observed in four cases and normal karyotype in two cases. No differences in the cytological‐cytogenetic picture of our patients with de novo EL and with therapy‐related EL were found suggesting that aetiological factors and/or pathogenetic mechanisms common to EL and secondary leukaemia may exist. All patients with MAKA had leftward shift of erythropoiesis with proerythroblasts and basophilic erythroblasts usually representing more than 50% of all erythroid cells. In patients with MIKA or normal karyotype, maturation of erythroid cells, though morphologically abnormal, was quantitatively preserved and early erythroblasts never exceeded 25% of erythroid cells. Clinically, the haemoglobin level at presentation, as well as in the proportion of patients achieving complete remission after chemotherapy, appeared to be lower in the maturation arrest‐MAKA group as compared to the preserved maturation‐MIKA/normal karyotype group. Median survival was shorter in the former group (3.5 months) than in the latter (median 13 months). Morphologic‐immunologic‐cytogenetic studies thus allow for the identification of two distinct cytogenetic‐clinicopathological types of EL.

Cytogenetic and Clinical Investigations in 76 Cases With Therapy-related Leukemia and Myelodysplastic Syndrome

Clinical, cytomorphologic, and cytogenetic investigations were carried out in a series of 76 secondary MDS and ANLL. Chromosome abnormalities were more frequent in patients with a history of multiple myeloma or macroglobulinemia (92%) and myeloproliferative disorders (82%) than in patients with previous breast cancer (40%). The secondary hematologic malignancies were mostly a trilineage bone marrow disorder. The most commonly found cytogenetic anomaly was monosomy 7, followed by total or partial loss of chromosome 5. In addition six other chromosomes, i.e., chromosome 3, 8, 9, 12, 17, and 21 seemed to be consistently involved in the pathogenetic mechanisms of secondary leukemia and MDS.

Deletions of the long arm of chromosome 7 in myeloid disorders: loss of band 7q32 implies worst prognosis

Clinical and cytogenetic data were analysed in 54 patients with acute non‐lymphocytic leukaemias (ANLL) or MDS (myelodysplastic syndromes) and deletion of the long arm of chromosome 7 (7q−), in order to determine if there is a commonly deleted region in 7q and to establish possible correlations between karyotypic features, such as karyotype pattern, karyotype complexity, associated anomalies, and/or the type of deleted segments, and outcome of patients with these disorders.

High-incidence of Chromosome-abnormalities in Igg3 Myeloma

Chromosomes were studied in 33 untreated myeloma patients, and results were correlated with the class of Ig secreted by the myeloma cells. A high incidence of clonal karyotypic anomalies seemed to be present in IgG3 myeloma patients, in whom the disease was advanced at diagnosis and rapidly progressing. Among the chromosome anomalies, the t(11;14)(q14;q32) was particularly prominent, and this chromosome anomaly, in analogy with the Ph1 chromosome, may characterize a family of lymphoproliferative disorders.

3q-, 3q+ Anomaly in Malignant Proliferations in Humans

Anomalies of both No. 3 chromosomes, of the t(3q-; 3q+) type can be observed in human malignancy as reported previously. It is our experience that this anomaly is found predominantly in myeloproliferative disorders, as a rather rare event, though occurring more frequently than similar exchanges between other homologous chromosomes. Previous claims about a relationship between this anomaly and thrombocytosis could not be confirmed, but the features found in a few patients indicate that further research should be undertaken to clarify this point.

FISH identifies different types of duplications with 12q13-15 as the commonly involved segment in B-cell lymphoproliferative malignancies characterized by partial trisomy 12

Clinical, cytogenetic, fluorescence in situ hybridization (FISH), and Southern blot data of 18 patients with different subtypes of B‐cell non‐Hodgkins lymphoma, cytogenetically characterized by partial trisomy 12, are presented. These chromosomal changes occurred predominantly in clinically progressive chronic lymphocytic leukemia, mixed cell type, and advanced‐stage follicle center cell lymphoma at the time of relapse or transformation into diffuse large cell lymphoma. Partial trisomy 12 consistently included the long arm of chromosome 12, either completely or partially, and resulted from dup(12q) or other rearrangements involving chromosome 12. The duplications were cytogenetically identified as dup(12)(q13q23), dup(12)(q13q22), or dup(12)(q13q15) in follicle center cell lymphoma or t(14;18)‐positive diffuse large cell lymphoma; dup(12)(q13q22) or dup(12)(q13q24) in chronic lymphocytic leukemia; and dup(12)(q13q21) in a case of t(14;18)‐negative diffuse large cell lymphoma. FISH, using library probes and a panel of YAC probes, mapped along the long arm of chromosome 12, confirmed the cytogenetic results in all cases analyzed except for three cases of t(14;18)‐positive follicle center lymphoma or diffuse large cell lymphoma with dup(12q). In these cases, FISH showed similar, possibly identical, duplications, which involved a region more centromeric (12q11‐21) than assumed by karyotypic analysis (12q13‐22 or 12q13‐23) and included alphoid DNA sequences, a combination hitherto unknown. In addition, commonly duplicated regions of chromosome 12 could be defined: 12q11‐21, including alphoid DNA sequences for follicle center cell lymphoma or t(14;18)‐positive diffuse large cell lymphoma, 12q13‐22 for chronic lymphocytic leukemia, and 12p13‐q15 for marginal zone cell lymphoma, all of which overlapped in 12q13‐15. Whether these regions, especially 12q13‐15, may contain genes which are important in malignant transformation or disease progression of B‐cell lymphoproliferative malignancies characterized by complete or partial trisomy 12 remains to be determined. Genes Chromosomes Cancer 20:155–166, 1997.